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  • Ya Gao 8:53 pm on November 20, 2015 Permalink | Reply
    Tags: , , , Scombroid poisoning, , seafood toxin   

    7 Customers Showed Symptoms of Scombroid Fish Poisoning after Eating in a Sydney Café 

    Seven people fell ill and showed symptoms of scombroid poisoning after eating from the same food outlet in the Sydney CBD, Soul Origin café, in late February 2015. The tuna, which was served in sandwiches at the café, was suspected to have caused scombroid poisoning.



    The New South Wales (NSW) Food Authority in Australia investigated that the canned product “John Bull Tuna Chunky Style in Sunflower Oil”, which Soul Origin café used, is a product of Thailand and imported into Australia by a Victorian company. This minor brand was used predominately in catering; it was not generally available to the public. The outbreak was not widespread and all affected product was removed from the market immediately.



    The NSW Food Authority tested the leftover tuna salad at the café to have 3950 micrograms of histamine per kilogram of tuna. The test result was well above the acceptable limit of 200 micrograms histamine per kilogram of fish.

    Scombroid poisoning is an allergic-type reaction to elevated levels of histamine in fish. It occurs when an enzyme produced by naturally occurring bacteria in certain fish species (including tuna, sardines, mackerel, swordfish, and marlin) convert histidine in the fish to histamine. Elevated levels of histamine amino acids in the fish produce cause the food poisoning. The temperature abuse of the fish produce at the catching or processing stage is usually the cause of the scombroid poisoning. The presence of high level of histamine in fish shows that decomposition of fish produce has occurred. The histamine toxin is not inactivated by ordinary cooking methods, and the contaminated fish will not necessarily appear spoiled.

    Symptoms of histamine poisoning occur quickly, usually within 30 minutes or a few hours upon ingestion of contaminated fish. The symptoms typically last for a few hours. However, in some cases, they can last for several days. Common symptoms of histamine poisoning including peppery or metallic taste sensation, tingling of mouth and lips, skin rash or itchy skin, headaches, and dizziness; nausea, vomiting and diarrhea may also occur in some cases. People with scombroid poisoning may be treated with antihistamines. Scombroid poisoning is rarely fatal, but it was thought to have killed a Australian mother and daughter, Noelene and Yvana Bischoff, while they were on vacation in Bali in January 2014. However, the case is extremely rare.

    Here is the news article on the tragedy happened in Bali:

    Histamine poisoning is rare, and there have been less than 10 outbreaks of histamine poisoning with 187 people diagnosed with the poisoning in Australia over the past 10 years.

    Since histamine is not destroyed by heat treatments, buying seafood from reputable sources to ensure the product is kept refrigerated when it is being transported and stored becomes the best way to protect us against scombroid poisoning.

    News sources & Reference:
    Australian Broadcasting Corporation, 2015. Scombroid Fish Poisoning Linked to Sydney Café after Four Customers Fall Ill. Retrieved from

    Australian Food News, 2015. Canned Tuna Food Safety Scare Linked to Thai Factory. Retrieved from

    Canadian Food Inspection Agency, 2012. Food Safety Facts on Scombroid Poisoning. Retrieved from

    Daily Mail Online, 2014. Australian Mother and Daughter Who Died in Bali Hotel Room Victims of Rare Fish Poison. Retrieved from

    Food Standards Australia New Zealand, 2015. Histamine (Scombroid) Fish Poisoning. Retrieved from

    New South Wales Food Authority, 2015. Update: NSW Food Authority Investigation into Scombroid at Sydney Café. Retrieved from

    • ColleenChong 8:14 pm on November 22, 2015 Permalink | Reply

      Very interesting article! I really like how you were display two cases of Scombroid fish poisoning to display the common reason that this food-borne illness occurs. From the two articles storage and transportation temperatures of fish seems to be crucial since it is due to bacteria converting histidine to histamine. As you have mentioned that the production of histamine is often due to the decomposition of the fish. I think that it is important that Health authorities do increase monitoring of quality of imported fish and histamine levels. Although the cases of scombroid poisoning seems to be rare it might occur without detection because the symptoms of poisoning is common with other illnesses. I think increasing the surveillance of Scombroid fish poisoning would be beneficial to the public because it is a preventable food-borne illness through proper manufacture, retail and consumer practices.

    • Susanna Ko 12:27 am on November 24, 2015 Permalink | Reply

      That is really unfortunate because the high levels of histamine are not reduced with cooking, so it’s really about the handling of the raw fish prior to processing it. I thought that the food processing plant would test their raw and finished products on the histamine levels. One would think that regulations and HACCP would prevent this kind of occurrence, especially in ready-to-eat hermetically sealed canned foods.

    • amreenj 3:19 pm on November 30, 2015 Permalink | Reply

      Great article! It is scary to see how much histamine there really was in the left over tuna, having 3950 micrograms/ kg is well over the acceptable limit of 200 micrograms/kg and could lead to severe complications as a result. Often with temperature abuse, it may be difficult to tell that this has occurred unless there are distinct/ obvious signs such as spoilage, odour, or colour change. I would think that there would be measures in place to firstly prevent this from happening, secondly to prevent this type of fish from being packaged, and thirdly that once opened chefs are able to detect that there may be something wrong with a fish (ie. if there is odour etc.). Histamine reactions can be fatal and as such, extra precautionary measures must be in place to prevent such things from occurring.

    • Mandy Tam 9:35 pm on December 1, 2015 Permalink | Reply

      This article provides a lot of good information about seafood poisoning. I have learn a lot.

      I know CFIA tracks histamine level in all imported fish products from the tour I have in FNH 326 in CFIA. CFIA has a specific import inspection program and one must get a fish import license to permit to import and sell fish in Canada. If someone is selling fish to restaurant or retail store without permit, he/she might be on conviction by indictment. The person might need to face jail time or/and paying a fine. Therefore, there is extensive tracking in Canada. I wonder what is the regulation/ surveillance Australia has on preventing fish poisoning from imported food. Anyhow, this is a very lucky case that no one died because of the outbreak.

      Link to CFIA:

    • elaine chan 12:08 am on December 2, 2015 Permalink | Reply

      Interesting article! I liked how you provided a detailed explanation as to what scombroid poisoning is, and its relation to histamine levels. I find it really amazing how a product containing 3950mg of histamine per kg of tuna was even allowed to be distributed for sale, when it’s way over its acceptable limits. It makes me question whether the manufacturer of this product performs quality control testing to ensure that their product is safe for consumption. Thankfully, this product was not for sale that’s available to the general public, or else its consequences would have been much, much more severe. However, it still caused a food borne outbreak that I felt could’ve been prevented through more strict quality control measures. I hope that the cafe does not suffer a major customer loss from this incident because they are the innocent victims. They are the consumers, and typically in cafes or restaurants, products such as canned tuna, are purchased with the assumption that they are safe and ready for consumption. I feel that both Thailand and Australia should implement more strict surveillance to ensure that exported and imported food products are safe for the general population for consumption.

    • flyingsquirrel 4:35 pm on December 2, 2015 Permalink | Reply

      What I find interesting about this article is that it shows that it is not just bacterial pathogens that produce toxins that are harmful once consumed (for example Clostridium botulinum, dinoflagelettes ). There are many naturally occurring endogenous substances that are potentially toxic in high amounts and I am glad this article brings that into light. I think many people in general that do not work or study in food safety will often overlook this and it is important to be aware that proper storage of foods is not only important for preventing bacteria proliferation, but also for preventing unwanted enzyme activity to keep foods delicious and safe. I think one reason why the monitoring of the tuna products imported seems inefficient may be due to the fact that it is not sold in the mass public market. Perhaps allocated resources left for inspecting certain products were unequally distributed based on the size of the target market?

    • YaoWang 12:17 am on December 15, 2015 Permalink | Reply

      It’s interesting that people can get sick by eating “allergic” fish. But it’s unfortunate to know that we can neither get rid of the histamine through normal cooking methods nor distinguish between fresh and spoiled fish. Apparently the problem can be caused by many microorganisms, rather than just the pathogens and therefore, is of great concern. So, I’m wondering what we could do to prevent such food-borne illnesses in the future?

    • CandiceZheng 2:37 pm on December 15, 2015 Permalink | Reply

      Thank you for sharing the seafood poisoning case with us! And I personally feel it is very unfortunate that although we understand that histamine level can indicate the degree of seafood decomposition, for the normal population there is no easy way to differentiate whether there is high level of histamine on the seafood. As indicated in the post, the leftover tuna salad at the café have 3950 micrograms of histamine per kilogram of tuna, which is well above the acceptable limit of 200 micrograms histamine per kilogram of fish. However, people still couldn’t observe any unusual appearance from these tuna. In this case I think it is very important to have some quick and easy way to examine the histamine level on seafood. For example, using something like pH test strips that are cheap, easy to use, and handy for the general population to use to test the histamine level on seafood in order to prevent further poisoning issues.

    • DeniseZhang 7:37 pm on December 15, 2015 Permalink | Reply

      According to the food chemistry courses that I am taking this term, histamine is a product from decarboxylation reaction of histidine. On immunological aspect, histamine can cause inflammation in human bodies (which is good while fighting pathogens), and it can also lead to hypersensitivities (a.k.a. allergy) in human bodies. I did not know that we have histamine poisoning issue in our life. Even though it is an extremely rare case, I do believe that we need to pay attention to it as undesirable inflammation is annoying. I really wish food provides can know more about those potential risks in foods, so that we can have foods more safely.

  • BarbaraCorreiaFaustino 3:48 pm on November 20, 2015 Permalink | Reply
    Tags: Cheese, Dairy, , , , , ,   

    Another multistate Listeria outbreak: this time from contaminated soft cheese 


    Recalled soft cheese products. Source: CDC

    An outbreak regarding soft cheese contaminated with Listeria monocytogenes finally arrived to a conclusion after five years of investigation. Starting in June 2010, thirty cases of listeriosis caused by the consumption of a specific type of cheese happened throughout the United States. Most of the cases were reported in California, but there was also a great number of cases happening specially in the eastern portion of the country, occurring in nine other states. According to the Center for Disease Control and Prevention, aside from California, there were also cases in Colorado, Illinois, Massachusetts, Michigan, New York, Ohio, Tennessee and Washington, and overall the outbreak resulted in 28 hospitalizations and 3 deaths, two in California and one in Ohio. Five illnesses were pregnancy-related, and one resulted in miscarriage.

    The Center for Disease Control and Prevention was able to link all those cases together using whole genome sequencing, which is a molecular subtyping method that is recently becoming more used by publich health authorities to identify foodborne pathogens. This method relies on sequencing the nucleic acid of the target microorganism and detecting the differences in that nucleic acid sequence.


    People infected with the outbreak strains of Listeria monocytogenes by contaminated soft cheese. Source: CDC

    Whole genome sequencing, as its name suggests, is a method that provides a nearly complete sequencing of bacterial nucleic acids, and that is what makes it a very accurate method, since it becomes much easier to compare and differentiate between serotypes of a specific bacteria. The first generation was not very user-friendly for the detection of foodborne illnesses outbreaks, as it was a very time-consuming, labor-intensive and expensive method. However, nowadays the development and improvement of next-generation sequencing methods have made these tools more available and affordable for laboratories, making it easier to use them routinely and ensuring not only precise, but also fast results, and at a reasonable cost. These methods are rapidly becoming more accepted by public health and regulatory agencies, and in the next few years they will probably replace the most commonly used method currently, which is pulsed-field gel electrophoresis (PFGE). Compared to the latter, whole genome sequencing methods have a higher discriminatory power for outbreak detection and allow for the sequencing of different pathogens in the same batch.

    The whole genome sequencing methods provide better discrimination between the subtypes, and therefore it can distinguish isolates that have a similar or equal PFGE profile, therefore improving the detection of a possible outbreak. This is what happened in this case, as the public health agencies could not properly connect all the cases that happened throughout the country with only one pathogen for over five years, and the whole genome sequencing showed that five rare DNA fingerprints of Listeria monocytogenes were related, connecting serotypes identified in this last August with serotypes found in the cases from around five years ago.

    The types of cheese involved in this outbreak were soft cheese, including Middle Eastern, Eastern European, Mediterranean and Mexican-style cheeses. The contaminated products likely responsible for the outbreak were from the brands Karoun, Arz, Gopi, Queso Del Valle, Central Valley Creamery, and Yanni, all of which were manufactured by Karoun Dairies, Inc. This company announced a voluntary recall of the products from those brands and stopped the production of other cheese products that might be contaminated with Listeria on September 16, 2015.

    Even though the incident was not very recent, a lot of restaurants and people may still have cheese products from those brands as the recall happened this year, and they are advised not to serve or consume these products as they may be contaminated with Listeria monocytogenes. It is very important that people don’t consume them, as listeriosis is a very severe disease, specially for children, the elderly and immunosuppressed population.

    Centers for Disease Control and Prevention. (2015). Multistate Outbreak of Listeriosis Linked to Soft Cheeses Distributed by Karoun Dairies, Inc. (Final Update). Retrieved from:

    Zuraw, L. (2015). Final Update: 3 Deaths, 30 Illnesses in Outbreak Linked to Soft Cheese. Retrieved from:

    Wiedmann, M. (2015). Use of Whole-Genome Sequencing in Food Safety. Retrieved from:

    • cvalencia 10:47 pm on December 3, 2015 Permalink | Reply

      I don’t really consume a lot of soft cheeses, but it is interesting to know that there is a risk associated with it. Listeriosis is a very serious problem, especially for high-risk individuals (immunocompromised people and pregnant women). I heard of a case where a mom-to-be had a miscarriage because of eating soft cheese contaminated with Listeria, while on vacation.. Sad how these things can happen, so everyone should be aware of such risks.

    • Carissa Li 2:58 am on December 13, 2015 Permalink | Reply

      It is pretty cool how we can still investigate the same pathogen DNA from 5 years ago to identify its type using whole genome sequencing. As we all know, soft cheese is under category 1 according to the regulation from Health Canada, so it can grow throughout the stated shelf life. Listeria is known to be tolerant at low temperature, that’s why it is not surprising that it can grow on soft cheese. This case happened around 5 years ago so I think the risk of having Listeria contaminated soft cheese from this industry is not that high now if no new cases occur after that. But of course being caution is priority to not having any chance of getting sick!

    • MichelleLui 9:05 pm on December 18, 2015 Permalink | Reply

      Good summary of recalled soft cheese and how it relates to the techniques learned in class. Soft cheese belongs to Category 1 RTE foods. Consumers should be educated on the risk of consuming food listed under Category 1 RTE foods. Especially the high risk groups, such as children, elderly, pregnant women and people with weakened immune system.

    • mustafa akhtar 12:25 am on December 19, 2015 Permalink | Reply

      I am happy that the surveillance methods available in the industry are growing and developing. However, coupled with this, it is very important that we educate the public as well. It is not uncommon to hear of miscarriages happening because of consumption of soft cheese. As they say, prevention is better than cure.

  • Stephanie Chen 11:37 am on November 20, 2015 Permalink | Reply
    Tags: , , , ,   

    Listeria Seizes the Oppor-tuna-ty! Denmark investigates outbreak linked to smoked fish products 


    August 2015. Four people sickened by Listeria in fish products linked to fish company, Hjerting Laks, in Denmark. Earlier in May, five cases of Listeria with two deaths were detected in Denmark. Two out of the five were of the same strain of Listeria that caused 40 cases and 16 deaths in deli meats in 2014. Although the current outbreak is not linked to the one last year, one of the five in May was traced back to Hjerting Laks.

    Unique culprit. While all tested samples did not reveal to have Listeria above the accepted limit, the Danish Veterinary and Food Administration (DVFA) found that Listeria isolates from the patients and samples taken from the company’s production area, equipment, and official food samples gave a DNA match after whole genome sequencing. The Listeria monocytogenes ST6 sequence pattern specific to this outbreak has not been detected in samples from other sources.

    Suspect: smoked fish. The source of infection in exact products has not been confirmed by the DVFA, but smoked salmon was suspected due to patients’ common consumption prior to illness. An outbreak of Listeria connected to Hjerting Laks was related to smoked halibut in November 2014, after which changes in the production processes were made. Hjerting Laks states that the bacteria from the current outbreak may have originated from raw materials supplied by sub-contractor.

    “We have ordered the company to change its routines with regards to production and own-check scheme,” says Annette Perge, head of unit in the DVFA. “Tightened supervision” has been placed on the company, and DVFA has advised customers to discard related fish products or return them to the place of purchase.

    Listeria monocytogenes. A gram positive, facultative anaerobic bacterial species capable of causing infections that may lead to symptoms of fever, muscle aches, and diarrhea. Populations including those with compromised immune responses due to age, pregnancy, and disease are typically at higher risk for listeriosis, with possible deadly effects on fetus and newborn infants. The primary route of transmission for this pathogen is through food, and especially in ready-to-eat foods that support bacterial growth of L. monocytogenes.

    But smoked fish? Yes, smoked fish. Smoked seafood including salmon, trout, tuna, oysters, etc., are manufactured in two primary forms: cold-smoked and hot-smoked product. Typical temperatures used for cold-smoking (22-28°C) are inadequate to inactivate L. monocytogenes, but levels of the pathogen present on raw salted fish are usually reduced by 90-99% during the cold-smoking steps of salting, drying, and smoking. Hot-smoking involves initial drying at 30-40°C, then smoking at 60-70°C followed by a second drying procedure. However, products may be contaminated after both cold and heat treatment in the processing environment while products are sliced and vacuum packaged. It also doesn’t help that Listeria can grow at refrigeration temperatures and is relative resistant to heating, acidic and high salt environments, as well as other inhibitory compounds used on foodborne microorganisms.


    See diagram. Production process has multiple opportunities for contamination. (Where else do you see places for Listeria to sneak in?)


    Recommendations for persons at high risk (weakened immune system) from the CDC:

    • Do not eat refrigerated smoked seafood, unless it is contained in a cooked dish (e.g. casserole)
    • Refrigerated smoked seafood, such as salmon, trout, whitefish, cod, tuna, and mackerel, is most often labeled as “nova-style,” “lox,” “kippered,” “smoked,” or “jerky.” (These are typically found in the refrigerator section or sold at seafood and deli counters in grocery stores)
    • Canned and shelf stable tuna, salmon, and other fish products are safe to eat

    Reduce risk for listeriosis from smoked fish by… Using ready-to-eat foods as soon as possible (product’s shelf-life shortens upon opening the packing). And remember to practice good hygiene in the kitchen!


    News sources:

    Listeria traced to Hjerting Laks despite fish products passing tests. (Aug 2015).

    Denmark investigates new Listeria outbreak. (May 2015).


    Joint FAO/WHO Activities on Risk Assessment of Microbiological Hazards in Foods. Case Study: Listeria monocytogenes in Smoked Fish (including digram). Retrieved from

    Report of the FAO Expert Consultation on the Trade Impact of Listeria in Fish. Retrieved from

    Center for Disease Control and Prevention. Whole genome sequencing. Retrieved from

    Center for Disease Control and Prevention. Tips for preventing Listeria poisoning. Retrieved from

    Image retrieved from

    • Michelle Ebtia 1:00 pm on November 29, 2015 Permalink | Reply

      This was a really interesting report! I do like smoked sockeye and always choose hot-smoked variety, however, after reading about the chances of cross-contamination post-production, I think I will avoid consuming them prior to further cooking and heating.
      Since the current measures seem to be rather ineffective, I did some research to find out about alternative methods for prevention and came across a paper that reports a novel approach in controlling the growth of Listeria spp on smoked salmon, through inoculating it with Carnobacterium maltaromaticum. The authors conclude that “the bioprotective culture C. maltaromaticum can extend the commercial shelf life of both hot and cold smoked salmon”, as it outcompetes the growth of the pathogen. However, I couldn’t find any reports of this method being put to practice by food manufacturers.

      Work Cited:
      Smith, D. (2012, July). Biopreservation: Control of Listeria monocytogenes Growth in Hot and Cold Smoked Salmon by Carnobacterium maltaromaticum CB1. In 2012 Annual Meeting. Iafp.

      • Jasmine Lee 2:02 pm on November 29, 2015 Permalink | Reply

        I really like the clever use of wordplay in your title. It highlights the opportunistic nature of Listeria monocytogenes to persist and grow in susceptible ready-to-eat foods. Given that L. monocytogenes is ubiquitous in the environment, I am not surprised that it would appear in fish, especially smoked salmon. There are Canadian regulations which require manufacturers to ensure sufficient lethality of their treatments and inactivation of their target microorganisms. If there are deviations in these standards, then the pathogen may remain and continue to be a problem. Furthermore, the smoking process is dependent on the smoke reaching the contaminated surface. The pathogen may be embedded in the flesh of the fish, where the smoke cannot make contact. Time and temperature abuse of the raw materials may also promote bacterial survival. As beautifully illustrated in your flowchart, I agree with the multiple routes of entry and carriers which contribute to the pathogen’s survival. The food matrix may be another factor since salmon is high in lipids. Fat is known to protect L. monocytogenes, which will present another challenge to eradicating this pathogen. As a consumer, I will probably reduce the consumption of this product or research more about the company before taking smoked salmon to the checkout.

    • AngeliMalimban 2:26 pm on November 29, 2015 Permalink | Reply

      I read a small article saying that Listeria does not normally survive the smoking process. However, it can still grow while being stored if it is done so improperly. It can grow heat-resistant endospores if it is not smoked to a high enough temperature either (source: Smoked fish can also be found in shelf-stable storage (I commonly see these at Canadian souvenir stores) where it is ready to eat. This can also have an equal risk of contracting L. monocytogenes, but there may be a common misconception that shelf-stable foods are safer to consume and that the likelihood of disease could be less.

      I actually LOVE smoked salmon, especially when I go get sushi (where they serve smoked salmon on top of sushi). It’s pretty scary because sometimes I just see the fish wrapped at room temperature on the sushi bar… it makes me wonder if it is actually refrigerated or left out there for the whole day. This is also consumed raw – and I should probably heat/cook it instead.

    • WinnieLiao 3:58 pm on December 3, 2015 Permalink | Reply

      First thing to point out is that your layout is easy to read and your wording is short and precise! I personally don’t like eating smoked salmon not only because of the fishy taste but also because of the salty and preservative content. The smoked salmon products I have seen in supermarkets are usually those vacuum packed. Just from looking at the product, I assume the producer processed their food by controlling water activity, using of preservatives and eliminating air. Knowing that Listeria is a relatively “resistant” bacteria that often is salt tolerant, dessication tolerant and facultative anaerobic, I can understand why it would survive so well in smoky salmon! Also another issue that comes to my mind, is that some First Nations people make their own homemade smoked salmon, which can be a possible food safety concern.

    • CindyDai 12:24 am on December 15, 2015 Permalink | Reply

      I agree what Winnie has said. There are a lot of other safety hurdles used in smoked fish industry to suppress pathogen growth. Lowering water activity, adding preservatives and vacuum packaging are all examples of other hurdles used. Since Listeria has high adaptation to tough environments, only multiple hurdles used simultaneously could ensure the effectiveness. However, as learned in lectures, sub-lethal treatments could cause increased resistance to other safety treatments, so the combination of safety hurdles must be well planned and proved by scientific test results.

    • Ya Gao 11:46 pm on December 15, 2015 Permalink | Reply

      The traditional preservation method, smoking, may not be safe for food processing if the raw material or the procedure after food processing is problematic. I love smoked salmon from deli area in Costco a lot personally. Although I cook them occasionally, I prefer eating them raw right away from the package. I will be more cautious in the future.

  • WinnieLiao 8:00 pm on November 19, 2015 Permalink | Reply
    Tags: , , , , Salmonellosis, , Tuna   

    Salmonella: in Frozen Raw Tuna? 


    Q: What’s the big problem here with Salmonella?

    A: A Salmonella seafood outbreak that hit United States has caused 62 sick across 11 states as of July 20, 2015. US CDC reported that there were 11 cases of hospitalization and no case of deaths. 97% of the infected population recalled the consumption of sushi with raw tuna a week before becoming ill. Results from laboratory and epidemiological investigations indicated that these people were likely infected with Salmonella Paratyphi B variant L(+) tartrate(+). Raw tuna processed in Indonesia by Osamu Corporation were confirmed responsible for 18 cases in California and some cases of infections in Minnesota.

    As a result, on July 21, 2015 Osamu Corporation called for a voluntary recall of two categories of items, frozen tuna and yellowfin tuna, processed in their Indonesian plant.


    Q: Isn’t Salmonella usually found in eggs and poultry?

    A: As known to the general population, Salmonella is often associated with foodborne illness due to its growth in poultry and egg products, as well as produce and complex foods. An interesting fact is that Salmonella is also a common pathogen found in seafood. Together with Shigella, these two pathogens constitute up to 10% of the reported foodborne illnesses in United States. Fish, shrimp, oysters and clam are food vehicles most often associated with seafood outbreaks.


    Want to know more? Here is a relevant video about Salmonella in seafood (published 3 years ago):


    Q: “Who” is Salmonella? Where is it from? How is it identified?

    A: Salmonella is a gram negative, rod shape, facultative anaerobic, non lactose fermenting bacillus with as much as 2500 serotypes identified. Transmission routes can include food-borne and water-borne, person to person and contact with animals. According to US FDA, Salmonella can be found in seafood that is intended for minimal processing and cooking.

    The source of this contamination can be traced back to the acquisition of the bacteria in polluted waters. Therefore to prevent outbreaks, current measures are carried out in harvesting waters before the final harvest. Another route of contamination can be traced to the processing and storage of the seafood.

    Laboratory test of stool samples from infected patients are used for diagnosis of salmonellosis. Further tests are required to discover the subtype of Salmonella responsible for the illness.


    Q: Yikes! What are the symptoms of salmonellosis?

    A: Salmonellosis, an infection caused by Salmonella, can cause acute gastroenteritis, accompanied by symptoms such as diarrhea, fever, and abdominal cramps from 6 to 72 hours. Headaches, nausea and vomiting in individuals may also be visible. However these symptoms usually disappear in 4 to 7 days, when many people recover. During this period, large volume of liquid is required to replace lost fluid from diarrhea. Severe manifestations include enteric fever, urinary tract infections, bacteremia and severe focal infections. Up to 10% of patients with typhoid fever can develop serious complications.

    In the circumstance of bacteremia, Salmonella can spread from intestines to blood eventually causing severe illnesses leading to death. Antibiotics may be applied to cure the disease, however antibiotic resistance is a perplex issue. Chronic pain in joints, urination pain and irritation of eyes can be some long term complications. In severe cases, chronic arthritis is observed in these patients.


    Q: Who is more likely to be infected? Are there any patterns that can be observed?

    A: Within the infected population, pregnant women, immuno-compromised individuals, young children (<5) and seniors (>65) are most likely at risk for developing severe disease. Consequently these individuals are advised to avoid consumption of raw finfish and shellfish. Patterns have been recorded regarding age and season: infants and elderly are on top of the list for being most vulnerable to salmonellosis; those infected individuals who consume contaminated food during the summer and early fall seasons are likely to contribute to the infection numbers.


    Q: What about… specifically Salmonella Paratyphi B variant L(+) tartrate(+)?

    A: Salmonella Paratyphi B variant L(+) tartrate(+) (formerly Salmonella Java) belongs to the subspecies of Salmonella enterica and is known to cause non-typhoid salmonellosis. In contrast, Salmonella Paratyphi B variant L(+) tartrate(-) causes paratyphoid fever.



    Q: How should we “wrestle” with the pathogen especially in seafood?

    A: Besides usual ways of avoiding foodborne illnesses, effective methods of preventing foodborne illness in specifically seafood, as suggested by US FDA, include:

    1. Washing hands, utensils and cooking surfaces
    2. Cooking seafood for 15 seconds at minimum of 145oF
    3. Avoid cross contamination by separating raw and cooked seafood
    4. Storing seafood below 40oF in the refrigerator or below 0oF in the freezer


    And finally… Questions for you!

    1. What is a possible reason for Salmonella to be able to grow in frozen raw tuna?
    2. What are some possibilities that the infection cases can occur over 11 states (possible routes)?


    Salmonella in raw tuna articles:


    FYI… Check it out! (References:)

    Epidemiology of Seafood-associated infections in United States:

    Facts on Seafood safety:

    Salmonella Q&A:

    WHO document on Typhoid Fever:

    WHO document on Non-typhoid fever:

    Government of Canada guidelines:

    Paratyphoid fever:

    Youtube video on this case:

    • csontani 4:37 pm on November 21, 2015 Permalink | Reply

      First of all, I really like how you format your blog! It’s definitely easy to read since the questions really help the readers to stay focused on the topic. Anyways, I think that most people just assumed that they can only be infected by Salmonella from eating raw eggs and poultry (in this case, there should be another way to inform people that it’s not limited to those sources). I remember getting infected with Salmonella couple of years ago from eating raw salmon, which I thought isn’t possible. But then I’m from Indonesia and I’m definitely not surprised that many people were infected by pathogenic bacteria from food. But I think that possible ways that the seafood is contaminated with Salmonella would be during the thawing process. And since they determined that all of the cases lead back to one source, I think that the main problem started from Indonesia where the tuna was imported from.

      • dgozali 1:42 am on November 23, 2015 Permalink | Reply

        Very interesting blog post and really great organisation of information! I think this really highlights the point that Salmonella can be associated with other types of food besides poultry and eggs. This personally scares me a little as I really love eating sushi and raw seafood. One of the reasons that Salmonella could have survived in frozen fish perhaps could be due to cross protection. If the pathogen was exposed to sublethal treatments it could develop resistance to subsequent steps in processing.

    • TamaraRitchie 9:54 am on November 23, 2015 Permalink | Reply

      Very nice layout. This was really easy to read and reminded the reader of key points. I think it may be possible for Salmonella to grow in the frozen tuna because freezing the sample will not kill Salmonella, it will just inhibit the growth, therefore when the tuna comes to room temperature when being served at restaurants it could cause illness and the bacteria could start to multiply. I think it is possible that the cases were so wildly spread because this company possibly distributed this product to varying states.

    • angel519 1:37 pm on November 24, 2015 Permalink | Reply

      As mentioned in the blog, improper handling practices during processing and store can contaminate the raw seafood with Salmonella; I think for seafood especially sashimi grade seafood, it is very crucial to have proper handling practices and clean production area to avoid contamination. Because Salmonella can survive the freezing storage temperature, once the seafood is defrosted, the pathogen will be able to start replicating and grow.

    • RainShen 11:23 pm on November 24, 2015 Permalink | Reply

      It is interesting that the frozen tuna was processed in Indonesia, which is such a far place in Asia. I’m not sure how the company transported the tuna to US, by ship or by air. If the frozen tuna transported by sea then it was possible the products underwent temperature abuse during the long distance transportation. Even if the tuna transported by air, the products may thaw a little during the transferring between different vehicles, e.g. truck and airplane. If Salmonella was in the tuna in the first place then it’s very difficult to eliminate the pathogens after, since Salmonella can survive under very low temperature. I agree that improper handling can be one of the main causes of the contamination as well. Foods like sashimi is very hard to cook for 15 seconds at minimum of 145F, which may loss the texture and raw taste.

    • KristinaRichmond 8:59 pm on November 27, 2015 Permalink | Reply

      Nice article! I agree that there are many points at which the fish could have become contaminated- poor storage temperature, thawing, or cross contamination all could have played a role in this outbreak. I always assumed that sushi fish would be sourced locally and a lot fresher. This goes to show that you really need to be a conscious consumer, and take the time to think about where the products you’re eating are coming from. However, I think sushi is a higher risk food and all this could have happened with local fish too, so it’s probably important for vulnerable individuals to avoid eating it.

    • Stephanie Chen 6:13 pm on December 1, 2015 Permalink | Reply

      Great organization of points! Importing the processed tuna from an overseas plant creates many more opportunities for contamination to occur. As the product is being transferred from place to place, and then furthered processed for consumption, multiple points could have allowed thawing and growth of Salmonella. According to the FDA Food Code (, certain temperatures and times for freezing are designated to kill parasitic worms. But this of course does not guarantee that raw fish products can become pathogen free. I agree that freezing only slows or inhibits the growth of Salmonella. However, it is truly a challenge for heat treatment of these foods that are intended to be eaten raw. Therefore, sanitary handling practices are crucial in decreasing risk of contamination.

    • cheryl lau 3:14 pm on December 4, 2015 Permalink | Reply

      This is an interesting article as Salmonella outbreaks are not typically associated with seafood. As stated in the article, the contaminated tuna was processed in Indonesia. Perhaps the cold temperatures that the products were subjected too were not cold enough to kill the bacteria and actually activated the stress proteins that made them survive other subsequent sub-lethal stresses. If the company was distributing the fish to the 11 states, perhaps their storage facilities or the mode of transport was contaminated and it could have affected all the shipments. Personally, I feel like there is always a risk when eating raw or partially cooked foods, but it would be a shame to give them up because of a fear of contamination. As long as restaurants or processors follow the proper handling procedures, consumers can feel safe enjoying these delicacies.

    • meggyli 11:48 pm on December 4, 2015 Permalink | Reply

      This is a really interesting layout for a blog with the Q&A. I don’t think I’ve seen anyone else do their blog this way! The Q&A definitely makes the blog easier to follow and highlights the important points. Again, it’s an article on a foodborne illness in which the pathogen involved is not commonly associated with the food. This article highlights the risks and dangers of operating a plant for raw and spoil-prone food, and in this case, tuna. Getting them overseas may be the cheaper option, but I feel that the risks associated with the long-distance travel and storage are not worth the money saved. Personally I would prefer eating locally farmed or wild seafood.

    • yichen25 1:02 am on December 11, 2015 Permalink | Reply

      I really enjoyed reading your blog post as the flow is well thought over. As for the questions you mentioned, I personally think that there is a possibility of the activation of stress response which enabled Salmonella to survive in extreme conditions, as learnt in FNH 413. Also, the stress response activated in Salmonella can also be applied in the survival in the host’s environment which further enhance their virulence. Therefore, it is vital to only consume raw seafood if it is certified to be safe for consumption or always cook the seafood to ensure the elimination of the seafood. I personally am a Sashimi lover and I guess one of the ways to avoid consuming contaminated seafood will be to only eat in a restaurant which is well reputable for the preparation of raw seafood.

    • Carissa Li 1:56 am on December 14, 2015 Permalink | Reply

      Your article is among all the simplest to read since they all start with a question and your answers are very detailed! It is very shocking to know that even frozen tuna can be contaminated by salmonella. Firstly is because it is rare to see samonella appear in seafood and secondly, we never learned that salmonella is tolerant to low temperature so this article really opened my mind! Eating raw food always has an increased risk of getting foodborne illnesses so getting the regulation straight and letting people know how to properly handle and prepare raw food is an important step to prevent any foodborne illness outbreak.

    • CindyDai 12:07 am on December 15, 2015 Permalink | Reply

      I really like your Q & A formatting. It really makes the blog more interesting and attractive to the general public. Public education on food safety practices is the most efficient way to prevent cross-contamination at the household level. It is also very interesting to know that Salmonella can survive cold treatment, such as freezing and refrigeration, and be present on raw seafood products. This indicates the importance of controlling initial contamination at the primary food production site. If we want to keep enjoying sashimi, microbiological quality control tests at the farm level are definitely necessary.

    • JorgeMadrigalPons 11:45 am on December 15, 2015 Permalink | Reply

      Salmonella is a very flexible organism and it can be a problem in many food products. When talking about seafood, preventing contamination may be difficult. Since seafood is often eaten raw, killing salmonella by cooking or high temperatures is not possible. Washing the tuna before preparing the dish might be a good preventive method.

    • CandiceZheng 2:47 pm on December 15, 2015 Permalink | Reply

      Salmonella again?!! It is such a nasty microorganism that would exist EVERYWHERE in our food system. I really appreciate the organization of your post: not only did you use the Q&A format, which makes the blog post very clear and simple to use, but the logic flow is clear and easy to follow. Besides, I like the practical advise you gave at the end. They are very helpful and easy to follow, and also based on scientific evidence that we learnt in class.

  • wen liao 3:31 pm on November 16, 2015 Permalink | Reply
    Tags: , Bangladesh, china, food adulteration, formaldehyde, formalin, ,   

    Week 7–Something Fishy about the Seafood Industry: Watch out on What You Eat! 

    Recently, the Food and Drug Administration (FDA) of the United States has been alerted that detectable amount of formaldehyde (which is known to the public as “formalin”) contaminated frozen fish was found at national grocery retailers in Greensboro, North Carolina. Usually, some fish species naturally contain a trace level of formaldehyde as one product of their metabolites. However, this metabolic product is produced in such small amount that it is considered undetectable. The laboratory confirmed formaldehyde positive result of these frozen fish indicated that formaldehyde has been intentionally added. It is later discovered that these formaldehyde contaminated fish products were originated from China and Vietnam.

    Formaldehyde, which is not commonly used in North America, is rather routinely exploited as a perseverative for fish in some Asian countries. Research (Sotelo et al., 1995) has shown that formaldehyde can prevent fish protein denaturation during frozen storage, keeping the flesh fresh for a much longer time. This is ideal for long distance shipping and trading—for instance, exporting fish and fish products from Asia to North America.

    In addition, this is not the first and only time that fish and fish products that originate in China and Vietnam are formaldehyde contaminated. In 2013, however, formaldehyde was also identified from frozen fish products in grocery stores in Raleigh, NC, according to Food Safety News (2013). These formaldehyde contaminated fish also originated from China and Vietnam, and they constitute up to 25% of the entire seafood imports from these two countries.

    Moreover, besides China and Vietnam, other Asian countries also have issues with formaldehyde application to seafood and fishery industry. Bangladesh (Rahman et al., 2015) for example, has long been suffering from formaldehyde adulteration on their fish products. According to the World Health Organization (WHO) (Liteplo, 2002), fish products have naturally occurring formaldehyde found in their flesh that ranges from 1 to 20mg/kg fish. However, the mean formaldehyde concentration in locally harvested fish in Bangladesh was 118.6mg/kg fish, about 6 times higher then the suggested value by WHO. This data strongly indicates that formaldehyde was intentionally added to the fishes, as unprocessed fish would not contain formaldehyde in such high concentration.

    The health risks associated with formaldehyde exposure are complicated. According to the National Cancer Institute (NCI, 2010) short-term health effects from formaldehyde exposure include watery eyes, nausea, skin irritation, and etc. Long-term exposure to formaldehyde can significantly increase the chance of getting cancer. Especially, it can increase the risks of acquiring leukemia and brain tumor.

    Although not as frequently reported as other food safety related concerns, formaldehyde adulteration in fish and fish products is still a potential threat to public health. Its occurrence might be relatively rare, but its complication can be devastating. Especially in Asian countries, where the population density is high but the economical development is low, limited public resources can make the treatment of formaldehyde exposure hard. Therefore, it is essential that the governments of corresponding countries take serious responsibility, carefully monitor their food production systems, making sure no unqualified products slip through.

    • Sotelo, C., Pineiro, C., & Perezmartin, R. (1995). denaturation of fish proteins during frozen storage – role of formaldehyde. Zeitschrift Fur Lebensmittel-Untersuchung Und-Forschung, 200(1), 14-23.
    • Imports and Exports: How Safe is Seafood From Foreign Sources? | Food Safety News. (2013, November 10). Retrieved November 15, 2015, from
    • Rahman, S., Majumder, M., Ahasan, R., Ahmed, S., Das, P., & Rahman, N. (2015). The extent and magnitude of formalin adulteration in fish sold in domestic markets of Bangladesh: A literature review. International Journal of Consumer Studies. doi:10.1111/ijcs.12238
    • International Program on Chemical Safety, Liteplo, R. G., & W. H. Organization, (2006). Concise international chemical assessment document, number 40: Formaldehyde World Health Organization (WHO).
    • Formaldehyde and Cancer Risk. (2011, June 10). Retrieved November 15, 2015, from

    • shinnie 12:43 pm on November 17, 2015 Permalink | Reply

      Wow, people are definitely creative when it comes to preserving foods. I know formaldehyde is commonly used to preserve dead organisms or specimens, but it is shocking to learn that industries would go this far in extent to use a chemical that is known to be highly toxic to humans to prolong the shelf-life of their products. I did a bit of research on formaldehyde regulations in Canada and it appears that our government acknowledges there may be residual levels of formaldehyde in inactivated veterinary vaccines (particularly bacterins), not much about formaldehyde adulteration relating to seafood and fishery industry though! They are also commonly used to produce resins and fertilizers in Canada. CFIA recommended methods to test for formaldehyde include: acetyl acetone titration, ferric chloride titration and the basic fuchsin test.

      • mustafa akhtar 1:57 pm on November 17, 2015 Permalink | Reply

        i wonder how protein denaturation would occur by freezing. From my understanding, it would have to be a strong compound to break the di-sulfide bonds in the protein structure. Can someone elaborate exactly how the protein structure is affected by freezing?

        • wen liao 7:54 pm on November 18, 2015 Permalink | Reply

          1. To put it simple: large ice crystals will form inside the cell during freezing, especially during slow freezing process. These ice crystals are so large that they will break the cellular membrane structure of the cells, causing destruction of the cellular structure and leaking of cellular components, which might result subsequent degradation of muscle protein…
          2. freezer burn

    • amreenj 1:57 pm on November 17, 2015 Permalink | Reply

      It is scary to think that individuals may be consuming formaldehyde without even knowing it! This article goes to show the extreme lengths that people in the food industry may go to increase the shelf life of products. With the expansion of food trade to a global level, it is becoming more and more difficult to avoid such preservatives in our foods. As mentioned in the post the exposure to these chemicals (ie. formaldehyde) can have serious and significant impacts on ones health. I think that the government needs to have stricter rules when it comes to internationally imported foods as well as with the liberal use of preservatives. Each country has different laws and regulations regarding the use of preservatives/ chemicals and we should make sure that these rules align with our country’s as well.

    • catherine wong 2:48 pm on November 17, 2015 Permalink | Reply

      This is quite surprising that some people would actually use formaldehyde on food products that are to be consumed. I remember in my high school biology class where we were dissecting pigs and the pigs were preserved with formaldehyde. The formaldehyde on the pigs had a really strong distinct odour so I wonder if the cooking masked the smell so people would not know what was in it while eating. I also agree that since formaldehyde has such serious impacts on health such as the risk of cancer through long term exposure, the government should think about setting stricter regulations and testing in imported products. Setting regulations is hard and would probably take years but would be necessary to prevent such high levels of formaldehyde contaminated food products from being consumed and harming people.

    • laurenrappaport 11:04 pm on November 21, 2015 Permalink | Reply

      It’s shocking to see what some people are using for the preservation of food! Especially when the longterm health effects are linked to cancer. Although this has not really been seen in North America, with all of the international trade that occurs in the food industry, it should be of major concern to everyone. I did not even think that a compound like this could be used as a preservative in food and that industries would use it knowing the negative health implications. I think that strict government regulations should be in place to test products for formaldehyde. As this compound naturally occurs in fish, it is important to test the levels to ensure the products are not further contaminated with formaldehyde to unsafe levels.

    • Silvia Low 8:35 pm on November 25, 2015 Permalink | Reply

      Well this is scary. I really hope that our CFIA/import inspection authorities are careful in what they allow into our food chain. It makes me wonder how they even detected the formaldehyde in the first place. Did customers complain of a different taste, or were they getting sick? Or did they just decide to one day inspect their fish products specifically for formaldehyde? It’s just such a random substance to test for in food.

    • MarinaMoon 11:40 am on November 26, 2015 Permalink | Reply

      It’s really scary what people would do just to make profit out of the products. There should be more strict regulations to restrict formaldehyde as well as other toxic products from being used as preservatives. What is the point of preserving food when it will result in negative consequences to people who consume them. This article indicates how food industries are more concerned about the presentation of the product than the benefits of the product to human health. Thus, we should take more consideration into what goes into the products that we will be consuming and also be ware that not all foods that has passed the inspection are safe to consume. On the brighter side, at least the researchers have identified the issue and hopefully would make amendments to prevent further use of formaldehyde as a preservative.

    • NorrisHuang 3:51 pm on December 1, 2015 Permalink | Reply

      I guess it is not that easy to detect formaldehyde in fish by tasting or smelling because fish (especially for imported/frozen fish as they are not as fresh) has this “fishy smell” which may mask the formaldehyde. Therefore it is really necessary to have strict government regulations regarding the permitted level of preservatives in fish. And I guess one way to avoid eating contaminated fish is to try eat local?

    • teewong 2:44 pm on December 11, 2015 Permalink | Reply

      First of all, you’ve got a very creative title, i like it a lot. I must say though, i am not surprised to hear about the extent that people will go about the methods in preserving food products. Unless someone really points out that certain food contains a certain hazardous chemical, we wouldn’t really second think about what types of dangerous chemicals we are consuming. Speaking from personal experience, sometimes when i feel a little bit nauseous or when i have a tiny migraine/headache, i would blame the lack of sleep or the amount of stress i’m going through. Never would I think it would be the food that is causing me to react in such ways. From now on, I will be more careful about the food I eat and i’ll be taking down notes for maybe when I seem to have reactions towards the food i consumed.

    • EmilyLi 9:07 pm on December 13, 2015 Permalink | Reply

      This is very interesting. I like that this article brought up the chemical agent that affect food safety, which gets less spotlight than more of the bacterial pathogens. As mentioned above, I too am not surprise to know that people would go as far as using hazardous chemical to preserve the foods. I guess this way they would be able to keep the fish meat in a better conditions, so consumers would be more willing to pay a higher price for them. However, many would not know that the expensive fish they buy would contain chemical that could harm them. Also even with the symptoms mention in the article there could be more complications that may not be discover yet. In my opinion, to limit the use of hazardous chemical in food would be having the government to set regulations as well as efficiently reinforcing them.

    • AngeliMalimban 9:17 pm on December 14, 2015 Permalink | Reply

      This is terrible to know that there are places in Asia that keep these practices in place. It makes me wonder how stringent the policies or the food inspectors of these respective countries are. I should be glad to live in Canada, where most of the fish is local or at least made within Canada (salmon, tuna, cod). Are there any other ways that fish imported from Asia last the long haul through to North America, Europe… etc?

    • EmilyChow 3:43 am on December 15, 2015 Permalink | Reply

      I can’t believe producers would add formaldehyde to products that people consume! In terms of food safety, it must be difficult to test for so many different contaminants and additives for all foods that are imported from foreign countries, but it’s important to find an effective method that tests for most contaminants efficiently. If formaldehyde-added fish is able to make its way to North American grocery shelves, then it makes me wonder what other contaminated foods are in grocery stores that we are not aware of.

  • shinnie 5:18 pm on November 13, 2015 Permalink | Reply
    Tags: , , Oysters, , skin lesion, V. vulnificus, Vibrio vulnificus,   

    Three Cases of “Flesh-eating”

    Bacterial Infections in Hong



    Three cases of necrotizing fasciitis— an infection caused by bacteria that destroys skin, fat, and the tissue covering the muscles in a short period of time—have been reported in Hong Kong during the month of July in 2015. Similar sporadic cases have also been reported in April and August of 2015 in Hong Kong. The affected include: an 82-year-old man and 78-year-old woman with underlying chronic illnesses and a 59-year-old man with good past health.


    The causative agent is a rare but deadly pathogen, Vibrio vulnificus and its name literally translates to “causing wounds” in Latin. V. vulnificus is one of the three major species of Vibrio, with the other two being V. cholera and V. parahaemolyticus both of which are pathogens of humans.

    Vibrio vulnificus

    V. vulnificus is a Gram-negative, lactose-fermenting, opportunistic (similar to L. monocytogenes), and motile curved bacterium commonly found in marine and estuarine environments. It is a moderate halophile (requires salt for growth) and is frequently isolated from oysters, clams, crabs, and other shellfish in warm coastal waters. It is responsible for causing 95 percent of all seafood-related deaths and has a mortality rate of over 50% in North America. The mortality rates varied in Hong Kong, being 35% for septicaemia cases and 20% for wound-infection cases.

    V. vulnificus has the ability to cause wound infections, gastroenteritis, or a syndrome known as primary septicemia. Infections among healthy individuals are acute and do not have long-term consequences; ingestion of this bacterium causes mild symptoms such as vomiting, diarrhea, and abdominal pain usually within 16 hours.

    In the immunocompromised population however, V. vulnificus can trigger further complications and has the potential to invade the bloodstream from an open wound or from the gastrointestinal tract, causing primary septicemia – a severe and life-threatening illnesses. This disease is characterized by fever, chills, septic shock that is soon followed by death. The three patients affected in Hong Kong had to either undergo amputation or excisional debridement.

    V. vulnificus (There are much worse pictures than this one!)

    Individuals are considered high-risk and vulnerable to infection if they have underlying chronic diseases or liver diseases [i.e. diabetes, cirrhosis, leukemia, lung cancer, acquired immune deficiency syndrome (AIDS), AIDS- related complex (ARC), or asthma requiring the use of steroid]. They are 80-200 times more likely to develop primary septicemia than healthy individuals.

    The infective dose for healthy individuals is unidentified but for immunocompromised persons, septicemia occurs with doses of less than 100 total organisms. The incubation period is 1 – 7 days after eating and the duration of illness ranges from 2 to 8 days. Diagnostic methods are similar to those used to detect common foodborne pathogens and revolve around culturing of the organism from wounds, diarrheic stools, or blood. Methods such as the Quantitative Loop-Mediated Isothermal Amplification can quantitatively detect V. vulnificus in raw oysters with high speed, specificity, and sensitivity.

    Measures that can be taken to prevent illness include:
    • Avoid going into the ocean with open wounds (I think most people neglect this)
    • Avoid eating raw or undercooked shellfish
    • Before cooking: Discard any oysters with open shells
    • During cooking: Boil for 3-5 minutes after shells open.
    • After cooking: Discard any oysters with shells that did not open.

    There have been many sporadic cases of V. vulnificus in Hong Kong over the past decade. Although the Centre for Health Protection of Hong Kong offers various Internet resources on how to prevent V. vulnificus infections, many of the victims are the elderly and are less likely to be able to access this information. I believe that more focus needs to be directed to relaying information on opportunistic foodborne pathogens to the elderly and immunocompromised in a manner that is not via the internet, i.e. various clinics and hospitals should offer them pamphlets and communicate with them verbally. In 2013, Health Canada has collaborated with the FAO, WHO, and the government of Japan to produce expert recommendations to the Codex Committee on Food Hygiene regarding V. vulnificus. Appropriate methods to monitor environmental hygiene and hygienic production, etc. can be found in Codex Alimentarius Guidelines on the Application of General Principles of Food Hygiene to the Control of Pathogenic Vibrio Species in Seafood.

    Questions for thought:

    1. Is this pathogen present in other geographical areas?

    2. Which method(s) would be most suitable to detect the presence of this pathogen based on it transmission route?


    Codex Alimentarius (2010). International Food Standards. Guidelines on the Application of General Principles of Food Hygiene to the Control of Pathogenic Vibrio Species in Seafood. Retrieved from:

    FDA (2015). Vibrio vulnificus. Bad Bug Book: Foodborne Pathogenic Microorganisms and Natural Toxins Handbook. Retrieved from:

    Han, F., Wang, F., & Ge, B. (2011). Detecting potentially virulent vibrio vulnificus strains in raw oysters by quantitative loop-mediated isothermal amplification. Applied and Environmental Microbiology, 77(8), 2589-2595.

    Lee, S. E., Kim, S. Y., Kim, S. J., Kim, H. S., Shin, J. H., Choi, S. H.. . Rhee, J. H. (1998). Direct identification of vibrio vulnificus in clinical specimens by nested PCR. Journal of Clinical Microbiology, 36(10), 2887-2892.

    Ma, J (2012). Vibrio vulnificus in food. Food Safety Focus, 72. Retrieved from:

    Stone, J. (2015). With Global Warming, Expect More Deadly Vibrio Cases. Pharma & Healthcare. Forbes. Retrieved from:

    Treasury Board of Canada Secretariat (2015). Food and Consumer Safety Action Plan. Retrieved from:

    Vibrio vulnificus (2013). Vibrio Illness (Vibriosis). Centers for Disease Control and Prevention. Retrieved from:

    • elaine chan 3:37 pm on November 14, 2015 Permalink | Reply

      Definitely an interesting, yet scary article! Commonly, food illnesses are related to gastrointestinal diseases, it’s my first time seeing how it can also lead to wound formation, and subsequently amputations and excisional debridements! This is definitely a wake up call for the food and marine industry to ensure the safety of their products for consumers. To determine whether or not this pathogen can be found in other geographical areas, I think it will be important to determine the pathogen’s favourable growth conditions and then evaluate which geographical areas has the potential of promoting the growth of such pathogen.

    • csontani 3:46 pm on November 14, 2015 Permalink | Reply

      This is definitely interesting to read! I’ve never heard of this pathogen before and it’s scary knowing what it can do to you. After reading this, the first question that popped in my mind was “is this pathogen a concern in where I’m currently living at?”. I certainly agreed with what you said regarding how the health agency should focus on older citizens who are immunosuppressed since they’re less likely to check the internet regarding the foods they’re eating. Maybe the food product packaging could have more information regarding the food and risks it may content or maybe health agency could talk to the senior care centre to give informations regarding these kinds of concerns.

    • angel519 10:24 pm on November 14, 2015 Permalink | Reply

      Since we live at the coast where we also consume oysters, clams, crabs, and other shellfish, and we also consume imported shellfish from warm coastal water; it is a potential pathogen that could be present at B.C. I think it is necessary to have warnings and publicize the risks of consuming contaminated shellfish to the general public. And for the high-risk population, especially the elderly, grocery stores can have brochures and signs by the shellfish section to tell them how to properly cook shellfish, symptoms of infections and to seek doctors if feel unwell after consumption. It is also important to have regular inspections on shellfish to prevent infected products spreading in the market.

    • Jasmine Lee 1:35 am on November 15, 2015 Permalink | Reply

      This pathogen is by far the most frightening of those that I have come across in this class. It is interesting to learn about a pathogen that thrives in environments with high salt levels. This is concerning since high osmolarity and low water activity are commonly used as hurdles for food safety and bacterial control. I also found it surprising that gender may play a role in regards to the pathogenicity of the V. vulnificus’ toxin. An article claimed that estrogen may assist in protecting against endotoxic shock and lowering the risk of mortality in individuals (Merkel et al., 2001). Furthermore, I agree with Angel that regular inspection of shellfish products and consumer awareness are critical for lowering the risk of exposure. It is also important to post signs along coastlines and have restaurants alert consumers about the associated risk with eating raw seafood. With many biological hazards in raw foods, I hope consumers are more diligent in terms of ensuring food safety and will make informed decisions for themselves.

      Merkel, S.M., Alexander, S., Zufall, E., Oliver, J. D. and Huet-Hudson, Y. M. (2001). Essential role for estrogen in protection against Vibrio vulnificus-induced endotoxic shock. Infection and Immunity, 69(10):6119-6122.

    • Susanna Ko 9:28 am on November 15, 2015 Permalink | Reply

      I find this article really scary because I can see my parents falling victim to this. There’s a lot of canned seafood products (clams, oysters) on the market. Cuisine with oysters is probably very popular as well. My parents like to add canned oysters into their congee. Perhaps popular asian newspapers should have a food safety section. I know my parents will probably read it.

    • cheryl lau 3:20 pm on December 4, 2015 Permalink | Reply

      This was a very scary article to read! However, I think it is necessary to point out the dangers we face when we expose ourselves to harmful microorganisms. Even though our bodies have defenses in place to fight invaders, they may not be as sound as we think. In this case, V. vulnificus caused serious consequences. I feel that most people in Hong Kong do not realize the serious affects that could follow from eating contaminated seafood. Specifically, the elderly or the people from our parents’ generation may not have been educated in food safety and I think these issues should be more prominent in the media.

    • EmilyLi 9:40 pm on December 13, 2015 Permalink | Reply

      This is a very interesting yet scary article to read. I think you title is very eye catching too. I personally like to eat seafood, and especially if you travel to coastal city like Hong Kong how could you resist the seafood there. Although in the article it mention that the pathogen is only high risk for immunocompromised individuals. However, with knowing that you are infected with a pathogen that is likely to breakdown flesh in your body is quite scary. Especially when you could catch those with just wound on you legs and going to the beach.

    • EmilyChow 3:25 am on December 15, 2015 Permalink | Reply

      It’s scary to think about these cases because they could potentially also happen here on the west coast of North America! This bacteria can possibly survive in pacific water conditions and contaminate the seafood we have here. In addition, seafood is imported and exported around the world so this is a concern for international seafood lovers. Since seafood can be enjoyed in different ways (canned, cooked, raw), it’s important to have strict processing regulations and make sure that such regulations apply for all pathogens, considering V. vulnificus is relatively rare.

  • CindyDai 3:07 am on November 13, 2015 Permalink | Reply
    Tags: Cyclospora, Cyclosporiasis, , , ,   

    Cyclospora Outbreaks are Hitting North America 

    Public health officials are warning about a series of Cyclospora outbreaks in US and Canada.


    From May to August 2015, 546 peoples from 31 states in US became sick due to Cyclospora infection. The U.S. Food and Drug Administration (FDA) indicated that this outbreak has been linked to imported fresh produce, including cilantro from the Puebla region of Mexico.

    Around the same time, a total of 97 Cyclosporiasis cases were reported in Canada, mainly in Ontario. Two cases were hospitalized, and no deaths were reported. The source of this outbreak was not identified.

    On October 17, CFIA announced that Costco Wholesale Canada is voluntarily recalling Alpine Fresh brand snap peas in Ontario due to possible Cyclospora contamination. At least 22 illnesses have been linked to the recalled snap peas.

    What is cyclospora?

    Cyclospora, a microscopic parasite, causes an intestinal infection known as cyclosporiasis. The parasite is typically found in imported fresh vegetables and fruits such as basil, cilantro, pre-packaged salad mix, mesclun lettuce, snow peas, and raspberries. People usually become infected with Cyclospora by ingesting food or water that has been contaminated with feces, and this parasite is most commonly found in tropical and subtropical countries. Cyclospora cannot be passed directly from one person to another.

    The life cyle of cyclosporiasis:

    Why I haven’t heard of it before?

    The public may not be as familiar with Cyclospora as some other foodborne pathogens because Cyclospora only came to medical attention about 40 years ago. This parasite was once primarily a concern for developing countries, but since the 1990s there have been more and more Cyclospora outbreaks in North America linked to contaminated imported fresh greens.

    How serious is the illness?

    Cyclospora is generally considered as a low-risk foodborne pathogen. Infected people usually experience watery diarrhea, stomach cramps, fatigue, weight loss, and abdominal bloating, while some people do not get sick at all. The illness may last from a few days to a month. People who have previously been infected can become infected again. The combination of 2 antibiotics, trimethoprim (TMP) and sulfamethoxazole (SMX), is used to treat Cyclospora infection.

    How can it be prevented?

    According to the US Centers for Disease Control and Prevention (CDC), avoiding food or water that might have been contaminated with stool is the most efficient way to prevent cyclosporiasis. Contaminated food may not look or smell spoiled. Both washing fresh produce and treating it with chlorine or iodine are not sufficient enough to eliminate the parasite. Microbial food safety hazards for fresh fruits and vegetables, including Cyclospora, must be controlled by addressing good agricultural practices (GAPs) and good manufacturing practices (GMPs).

    Here is an educational video about Cyclospora:

    For more information, please check out (References):

    CDC, 2015. Parasites – Cyclosporiasis (Cyclospora Infection). Retrieved from

    CFIA, 2015. Food Recall Warning – Alpine Fresh brand Snap Peas recalled due to Cyclospora. Retrieved from

    Cinnaminson N.J., 2015. Cyclospora Contamination and Infection Risks. Retrieved from

    Food Safety News, 2015. CDC: Cyclospora Outbreak Linked to Mexican Cilantro Sickened 546 People. Retrieved from

    Mulholland A., 2015. Cyclospora outbreak: What you need to know about the parasite, illness. Retrieved from

    • WinnieLiao 11:11 am on November 18, 2015 Permalink | Reply

      I really like how you organize the blog into Q and A! It makes the article so much easier to follow. Besides bacterial contamination in our food leading to foodborne illnesses, we probably often forget about other organisms such as parasites! Cyclospora is definitely one that is quite uncommonly known. I find the section on how serious the illness is and the prevention methods to be useful and informative! Regarding the ways of prevention, is there anything we can do as public to avoid the contamination? Would cooking for a certain amount of time be helpful in eliminating the parasite in our foods?

    • Stephanie Chen 5:39 pm on November 19, 2015 Permalink | Reply

      Very interesting and informative article! The video is helpful as well. I agree with Winnie that many people may overlook contamination in food other than the commonly heard-of bacteria. It is scary to think that these fresh vegetables and fruits that we may consume often in our diet, such as basil, cilantro, and pre-packaged salad mixes may be a source of parasites like Cyclospora. We need to remember that contaminated food does not always show visible signs of spoilage. Safe handling of fresh produce still needs to be practiced to decrease the likelihood of getting an infection!

    • KristinaRichmond 6:15 pm on November 20, 2015 Permalink | Reply

      I’d never heard of Cyclospora before, so thanks for the info! I think it’s interesting that the number of outbreaks has been increasing, and I wonder if it’s due to more contaminated food or just better testing and identification in recent years. It’s alarming that it’s found on fresh greens and isn’t killed by treated washing. I think this really ties into Justin’s lecture, and like you said addressing good agricultural practices.

    • flyingsquirrel 4:58 pm on December 2, 2015 Permalink | Reply

      This is quite alarming because as eating fruits and vegetables becomes more important in public health, the demand for production of these popular foods (salad mixes, peas etc.) also goes up. Many of these foods are produced south of the border and even to Mexico! I read in an article a couple months back on the recall for cilantro because there had been some sort of contamination. The article reported that upon inspection of the farm in which the produce was grown, they found used toilet papers and human fecal remains. It just brings shivers down my spine to find that something that this could have been prevented. However this also brings to light the conditions of workers on the farm in which they do not have a proper toilet.

    • teewong 2:59 pm on December 11, 2015 Permalink | Reply

      I feel that more people should be aware of how easily fresh produce could be contaminated with bacteria, viruses and parasites! Especially when it comes to vegetables that don’t require or are not meant to be cooked, it is really frightening to know that there’s very little that we could do as consumers to ensure our own food safety. Since chlorine wash technique is not a common method used in household, it means that there is even a higher chance for us to be affected by fresh produce than by consuming meat. I feel that prevention starting from the farm side is definitely a key in protecting the consumers. They should check their water irrigation system on a daily basis.

    • CandiceZheng 3:41 pm on December 14, 2015 Permalink | Reply

      Thanks for the informative blog! We’ve been discussing foodborne pathogens for the whole term and I have never heard about this pathogen before. I really appreciate your explanation about Cyclospora, which is very clear, informative, and well organized into Q&A format. It is quite shocking that there are many illnesses associated to the recalled snap peas, which is one of my favorite snack in my spare time. I’ve always considered it healthy and nutritious, but I never thought about the potential pathogen contamination associated with it.

    • YaoWang 12:25 am on December 15, 2015 Permalink | Reply

      Just as what other people have mentioned above, the blog is really informative as I’ve never heard about the microorganism before. And the format of the blog is really easy for us to follow. Thank you Cindy. By the way, I think at this time, people should really be careful when handling fresh vegetables as they are vulnerable to many food-borne pathogens.

  • Carissa Li 3:18 am on November 12, 2015 Permalink | Reply
    Tags: , cassava, Cholera, ,   

    Cholera Outbreak in Africa 

    Cholera, an infection that is commonly found in central Africa, has affected thousands of millions of people every year, according to the World Health Organization (WHO). Cholera is an acute diarrheal disease that is caused by the strains of a bacterium called Vibrio cholerae. V. cholerae is a pathogen that colonizes the small intestine and causes symptoms such as watery diarrhea and vomiting. If left untreated, people will suffer from severe dehydration and leads to death within hours.

    During March 2015, there were more than 10 students hospitalized after consuming cooked cassava tuber, which is a kind of African salad in Abakaliki, the capital of Ebonyi in Nigeria. They suffered from stooling right after the meal and went to hospital as the condition became worsen.

    After investigation, they confirmed that this is a case of cholera, and the food was contaminated by flies, the director of Rural health, Ministry of Health, Dr. Christian Achi explained.

    Cassava is a type of plant that is widely eaten as staple food in developing countries. That means many people eat it in a daily basis and if it is infected by V. cholerae, this can cause a huge outbreak of cholera in Africa. Therefore, cooking food thoroughly and maintain hygiene is very important in these areas to prevent any disease outbreak.


    Many of us think that keeping our equipment clean and fully cook food are the essential things that we should do and are enough to prevent any disease. We never thought of flies to be the transmission route of bacteria. Flies carry bacteria from contaminated food to other non-contaminated food and cause people to be infected. Therefore, keeping the environment clean to avoid any insects from contacting food is also a key to preventing cholera.

    According to the data provided by WHO, almost 45% of cholera cases were reported from Africa in 2013. Although the number of reported cases has already decreased compare to previous years, the reason why there are still more than ten thousand reported cases this year is probably due to flooding in Africa. This is because another way cholera contaminate food other than flies is through water. Flooding causes all the food soaked in dirty water and thus be contaminated by V. cholerae very easily. Also, due to all kinds of economical situations and limited water resources, people will drink water without processing such as boiling or filtering. As a result, cholera is widely spread in these areas where there is inadequate environmental management.

    Cholera vaccineThe method people use to treat cholera is by oral rehydration salts (ORS), a treatment that is indicated by WHO. Severe diarrhea will leads to dehydration so ORS is a very effective and efficient way on rehydrating people. Anitibiotics are also used to shorten diarrhea duration. To control the outbreak of cholera due to weather such as raining season, they will introduce cholera vaccines to people. The following video shows the situations people are facing in Africa and how they are treating cholera using vaccination. In order to prevent cholera outbreak, improving sanitation and access of safe drinking water are the keys, which are also indicated on the video. We shall not neglect the importance of improving environmental conditions such as household hygiene, water filtration, development of water pipe system by treating disinfectants, etc. These strategies can upgrade their living conditions and minimize the chance of getting infected.



    • BarbaraCorreiaFaustino 12:02 am on November 22, 2015 Permalink | Reply

      Such an interesting article! It is scary that even though the cooking utensils may be clean, the food can still be contaminated with the Vibrio bacteria and cause a severe diarrheal infection in the people that consume that contaminated food. Just like it is stated in the previous article about Cryptosporidium, it is very important to treat the water to make it potable in places where you cannot be sure if that water is safe, such as locations affected by flooding, to avoid being infected. Unfortunately, in some countries in Africa many people does not have access to potable water, so the local health authorities should make it a priority to provide drinkable water to prevent cholera outbreaks.

    • Silvia Low 8:31 pm on November 25, 2015 Permalink | Reply

      Reading this reminds me of how grateful I should be to live in a place where we have access to clean water all of the time. It’s silly how so many people take water for granted and don’t realize that people actually die from not having clean water almost every single day. It takes some as simple as teaching people the importance of boiling/sanitizing water before using it to save a life, yet deaths still occur. This is such a frustrating situation.

    • WinnieLiao 8:47 pm on December 14, 2015 Permalink | Reply

      Numbers do matter! Only Africa alone contributed 45% of Cholera cases. Contaminated water and food are some direct concerns, but these might also indirectly affect the population as well. Environments that are insanitary can be an ideal place for the breeding of flies and pests that can propagate illnesses. Furthermore contamination of water can only make matters worse when people consume it for rehydration. Using this water for irrigation of produces poses a concern. It is great to know that effort has been made to provide the area with ORS and that the problem of contamination has been recognized.

    • AngeliMalimban 9:11 pm on December 14, 2015 Permalink | Reply

      It’s crazy how much cholera is easily spread throughout to cause such an epidemic. Vancouver luckily does have one of the cleanest water supplies in the world – there are people I know who do not hesitate to drink from the tap (myself included). As Silvia said, we are definitely lucky. Sadly it does not seem like many places in Africa have an understanding about why CLEAN water is so important. Many many times do I hear stories about children that just grab water wherever they see it just so that they can have some water to drink. I think that it is very important that the government/ministry of health realizes that this is such an issue and that they make efforts to get education out there for the remote villages. That way, they can learn about HOW to properly sanitize food/water and how to prevent diseases, and why it is so important to do so.

  • DeniseZhang 1:58 am on November 12, 2015 Permalink | Reply
    Tags: BC, ,   

    Vibrios: Rare but Need to Notice 

    Eating raw and cold shellfish can be such enjoyment under the hot sun. Living in BC makes us have the advantaged access to fresh and tasty shellfish. However, sometimes such delicacy comes with ricks and the major ones are the toxins produced by other organisms that live with shellfish.

    According to Health Canada, Vibrios are toxin-producing bacteria that can be found naturally in water, fish and shellfish. Its main transmission is through consuming contaminated foods and drinks. Most of the pathogenic Vibrios are salt-loving, which means they live in oceans. For example, Vibrio parahaemolytius that caused an outbreak in Canada in the past summer.

    During May to September 2015, 82 cases of Vibrio parahaemolytius were reported (60 of them were in BC) to Public Health Agency of Canada. All cases were related to consuming raw shellfish especially oysters. Due to this outbreak, oysters harvested from British Columbia coastal waters for raw consumption on or before August 18, 2015 were recalled from the marketplace.

    In response to the the outbreak, Vancouver Coastal Health issued a statement on August 2, 2015 requiring restaurants to serve oysters after cooking as only oyster harvested from BC could be served raw at that time. Fortunately, this outbreak ended fast and well. The latest case was reported on September 3 and only one person was hospitalized. No death case was reported.

    People infected by Vibrio parahaemolyticus usually get mild intestinal illness. After 12 to 24 hours of incubation, most people develop one or more of the following symptoms: diarrhea (watery), stomach cramps, nausea, vomiting, fever and headache. Another pathogenic type of Vibrios, V. vulnificus can cause chills, abnormal low blood pressure and bacteria present in blood to infected individuals especially to the vulnerable. Symptoms last about three days and treatments are seldom required.

    More sever than two types above, people infected by V. cholerae usually develop one or more of the following symptoms after one to three days of incubation: diarrhea (watery), leg cramps, vomiting, dehydration and low blood pressure. Due to the rapid loss of body fluid, treatment (re-hydration with fluid containing electrolytes) or antibiotics in serious cases is required.

    1. Boil shellfish in shell until open and continue boiling for 5 minutes
    2. Steam until shellfish open and continue steaming for 9 minutes
    3. Do not eat shellfish that is not open
    4. Boil shucked shellfish for 3 minutes or fry them in oil for >10 minutes at 375°F (190°C)
    5. Drink water from reliable sources

    There is a video on youtube that gives a brief intro of Vibrios, check this out if you are interested:


    • ayra casuga 8:43 am on November 12, 2015 Permalink | Reply

      I like how your blog is about something that occurred both local and recently as this topic can easily apply to all of us living here in BC! This is a great example of how our food safety sector is doing an awesome job at monitoring potential outbreaks because of the short duration of the shellfish toxin outbreak.

    • TamaraRitchie 3:14 pm on November 12, 2015 Permalink | Reply

      I am curious to know how much this case cost the restaurant industry. In the summer months many tourists come to B.C to enjoy fresh seafood. Due to BC oysters not being able to be consumed raw at the end of the summer I believe many tourist would have chosen another restaurant or another type of oyster that may be more or less expensive causing a loss of income for restaurants. When outbreaks like this happen I feel many are more hesitant to consume raw oysters even after the ban is lifted.

      • laurenrappaport 10:42 pm on November 15, 2015 Permalink | Reply

        I remember hearing about this over the summer so its interesting to learn a bit more about it. Although I do not eat raw oysters myself, the consumption of raw oysters especially in BC seems to be on the rise. It seems like they are a hot food commodity and are in high demand especially in a city like Vancouver where we have access to such fresh seafoods. Even though this recall did not last very long, as you mentioned Vibros are naturally are found in water and more specifically, pathogenic vibros are commonly found in oceans. I wonder if this type of recall is likely to occur again and whether or not it occurs frequently?

    • NorrisHuang 5:11 pm on December 1, 2015 Permalink | Reply

      Raw oyster is absolutely delicious however it is sad that it is also associated with various food-borne diseases as it may be contaminated with microorganisms and toxins (as mentioned by Dr. Kitts in the guest lecture). And even though heating may be effective in terms of killing bacteria, toxins may still remain. I think the best alternative is to cook the oyster when ever possible and reduce the frequency of raw oyster consumption even though cooked oysters don’t taste as good.

    • cvalencia 4:34 pm on December 4, 2015 Permalink | Reply

      It’s a good thing that this is a rare case! I know a lot of friends who absolutely adore raw oysters. It is great to have awareness of such pathogens in our food, and so we can take precautions when consuming them. Hopefully restaurants can ensure that their raw oysters are free from these pathogens, to prevent the consumption of contaminated seafood. Does this pathogen also occur in other seafoods, or just mainly raw oysters? How is contamination controlled if the oysters are eaten raw?

    • Ya Gao 10:13 pm on December 15, 2015 Permalink | Reply

      I really enjoy eating raw oyster and now I know what caused all oyster dish to be served cooked this summer for a period of time. I am glad this is a rare case. Since the incubation period is short, the outbreak could be quickly identified and CFIA was acting fast toward the outbreak. Since this bacteria is naturally present in ocean, I am curious to know if Vibrios could also be seen from fish consumption?

  • ColleenChong 10:12 pm on November 9, 2015 Permalink | Reply
    Tags: Cryptosporidium, , , , ,   

    Warning: Water supply contaminated with the parasite Cryptosporidium 

    Most North Americans and Europeans consume fresh tap water daily without any concern. These developed countries have advance filter systems, implemented chlorine treatments and/or radiation treatments; such as ultraviolet light to kill pathogens. Since the water supply is treated many would believe the source is safe. Is that always true?


    This past August the water supply of several Lancashire districts in England (Blackpool, Preston, Chorley, Fylde, Wyre and South Ribble) was contaminated with an infectious parasite, Cryptosporidium. About 300,000 Lancashire households were put on alert. This parasite causes the disease cryptosporidiosis, which includes symptoms stomach cramping, dehydration, vomiting, nausea, and weight-loss. The most common symptom is watery diarrhea. These symptoms may appear after 2 days and last up to 30 days after infection. Chronic or fatal illness maybe develop in susceptible population; which includes immunocompromised, young children, and the elderly.

    This parasite is a concern when it comes to the consumption of tap water because it is extremely resistant to chlorine, therefore; the chlorinated treatments have little effect on the parasite. The water company United Utilities advised everyone to boil their water before consumption.

    Due this parasitic discovery panic was all over. A local mentioned, “This water thing in Blackpool is a nightmare just went to the corner shop and they were on the last few bottles!” Major supermarkets were running short bottled water since “nobody can drink the water in Blackpool because it’s contaminated and now there’s no water left in any shops.” With the high demand of water and the short supply, people were selling water on the internet for ridiculously high prices.

    Water shortage in Supermarkets

    United Utilises reassured the public that they were monitoring Cryptosporidium levels carefully through continuous testing. Only trace amounts remain in the source after the first week of August, United Utilities issued boiled water notice until mid-August.

    This is a rare occurrence. In 2005 an outbreak of cryptosporidium affected 231people in North Wales and the Cymrus Welsh Water was fined £60,000 and spent another £70,000 to compensate the affected individuals. As for the cryptosporidium contamination from August there were no confirm cases of sickness. An outbreak was avoided due to the quick action United Utilities took.

    Here’s a Brief video for your interest!

    Sources of contamination (fecal-oral route):
    • Animal waste
    • Water sources

    • Boil water
    • Proper hygiene
    • Wash hands

    • No specific drug to kill organism
    • diarrheal medicine may help slow down diarrhea
    • Consume lots of water

    What is your opinion on drinking tap water? Do you boil or treat your water?


    • yichen25 12:46 am on November 11, 2015 Permalink | Reply

      Growing up in Malaysia where we don’t have the privilege to drinkable tap water, it has been a practice for us to boil our water before drinking. Even after coming to Canada, I still continue to do so. I personally think that even with the advanced filtering systems and treatments, there is still the possibility of post-treatment contamination as the pipes that carried the water to household might be contaminated. Therefore, I strongly believe that boiling yr water before drinking is the best way to avoid being contracted with any unwanted diseases.

    • MarinaMoon 3:00 am on November 13, 2015 Permalink | Reply

      Similar to Yichen, back in Korea we always boiled our water before drinking because the tap water was not safe to drink. However, for me, after coming to Canada, I adapted a habit of drinking from tap water especially since I started living by myself. I never doubted that there could be a contamination in something that I consume everyday, but now I realized that I should be more concerned about what I consume and although it is still safe in Canada, to boil the water before drinking. It’s scary how there seems to be increase in pathogens that are resistant to so many sanitation practices. This particular pathogen only cause mild symptoms which is relieving, but I wonder what would happen when something more resistant and more pathogenic appear in food product or water that we consume everyday. In the future, there could be pathogens that arise which is resistant to chlorine and heat, which would further complicate the prevention process.

    • catherine wong 10:42 pm on November 13, 2015 Permalink | Reply

      This was an extremely interesting article. At home I always boil my water before drinking it because I’ve heard about tap water being unsafe to drink sometimes. However when I’m out in the public and didn’t bring enough boiled water from home, I do sometimes drink tap water. I also agreed with Yichen that full trust cannot be placed in advanced filter systems and treatments due to the possibility of post-treatment contamination and there could always be the chance of these systems failing. Sometimes just a flaw in the system could cause great problems and it was just nice to know that there were no confirm cases of sickness for this occurrence. After reading this article, I think I might refrain from tap water even if I’m a little thirsty because it doesn’t seem to be worth the risk of getting sick.

    • elaine chan 3:01 pm on November 14, 2015 Permalink | Reply

      Definitely an interesting article! Water intake is an essential element for human survival, so with an incident like this occurring, it is no surprise that it has caused a panic across the region. I feel rather grateful that I’m living in an area where water filtration systems are present, and the water is safe for consumption once it’s deposited from our taps. However, like Yichen mentioned, at times, there can be flaws in the water filter and treatment systems. Growing up, my family has always had the practice of boiling the water from our tap prior to consumption. It has become a common practice for myself as well , and it doesn’t seem to be a bad idea implement this extra step for safety measures.

    • RainShen 4:23 pm on November 15, 2015 Permalink | Reply

      The safety of drinking water was a big problem in the China before I came the Canada. My family definitely would boil the tape water before drink to make sure all the pathogens have been killed and the water is safe to consume. I know some households in China they do have their own water filter system at home for filtering and de-contaminating their drink water, since the tap water would not only contains some pathogens, but also some heavy metal ions. Therefore, wherever I go, I will boil the tap water if I wanna drink it. Even through the water treatment system here in Canada is very efficient, it may still get contaminated after the treatment before consumed by human.

    • amreenj 1:39 pm on November 17, 2015 Permalink | Reply

      Very interesting article! It is so scary to think that this contamination of drinking water occurred despite the precautionary measures in place to prevent such things from occurring. Having lived in Vancouver all my life, I hadn’t though about this ever occurring. However, I have travelled to a number of countries in which the problem of contaminated drinking water does frequently occur. I think that the quick action taken by the water company prevented a major outbreak of this chronic/ fatal disease. I think that this case serves as a reminder that we must still be aware of the potential for contamination in “safe” drinking water and that water companies should continue to ensure that their water is in fact properly sterilized.

    • JorgeMadrigalPons 10:57 pm on November 22, 2015 Permalink | Reply

      In Mexico, there is also big issues with drinking tap water, since it is not treated for drinking purposes. I almost never drink tap water in my country. Mostly, people buy bottled water for consumption, but many small local food businesses do not. I have heard of many outbreaks caused by the usage of tap water by ice-cream shops, taco shops, etc, (mainly food street). I think that it would be of great benefit to the health of Mexicans, if the gouverment implemented advanced water treatment systems.

    • dgozali 1:28 am on November 23, 2015 Permalink | Reply

      Very interesting article! Ive always been boiling my water before I came to canada but changed my routine when i started living here. I think this is a step that is often overlooked in countries where tap water is drinkable, yet it is probably the most crucial step in preventing outbreaks because water is needed by everyone for drinking and also for washing other foods. If the water has been contaminated, it can go on to cross contaminate fruits and vegetables that are washed with it.

    • Michelle Ebtia 11:13 am on November 29, 2015 Permalink | Reply

      I was initially surprised to learn that there are no effective treatments for patients infected with this parasite! So I did a quick research and found out that there is a moderately effective drug called nitazoxanide available for treatment. However more research needs to be done to come up with an effective option, which according to Miyamoto and Eckmann (2015), has not occurred due to insufficient funding, mainly because historically, this problem has only existed in developing countries. Since the case reported in this blog has happened in England, one might wonder if the research would now gain some momentum.

      Work Cited:
      Eckmann, L. (2015). Drug development against the major diarrhea-causing parasites of the small intestine, Cryptosporidium and Giardia. Frontiers in Microbiology, 6, 1208.

    • Mandy Tam 9:23 pm on December 1, 2015 Permalink | Reply

      I think chlorine is the major hurdle that most countries have in their water to eliminate pathogen. Knowing that this might not work 100%, I think this is more scarier than Lauren’s post. I think more and more I read the blogs, I really need to reconsider my own eating habits. Maybe I should start boiling my water before consumption.

      Anyhow, I am surprised how little researches have been done on such matter after reading Michelle comment. Maybe more surveillance and research should be done in such matter as a lot of people drink water from the tab.

    • teewong 6:43 pm on December 14, 2015 Permalink | Reply

      This is very interesting, especially when both occurrence happened verily close to each other. It makes me wonder if the water companies are taking every precaution to detect these sort of contaminations before it even affects the water. Also, I read from your prevention section that washing hands will help, but I was wondering with what water do we wash hands with when the tap source is contaminated already?
      This is a frightening problem to me since I live in Vancouver and we drink out of the tap 80% of the time when we visit restaurants. This could be a potential hazard for many of us if it were to happen in Vancouver as well! I can also see that companies that make bottled water will use this chance to profit from people as it would cause shortages on bottled water supplies when such thing happens.

    • MichelleLui 9:53 pm on December 18, 2015 Permalink | Reply

      Very interesting article! There are so many factors that could contaminate the city water, such as backflow, old pipes and etc.. Preventative measures such as putting in a reverse osmosis system and boiling water are recommended. I have a reverse osmosis system which works for me.

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