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


    source: http://www.abc.net.au/news/2015-02-26/scombroid-fish-poisoning-linked-to-sydney-cafe-tuna/6263120

    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.


    source: http://ausfoodnews.com.au/2015/03/11/canned-tuna-food-safety-scare-linked-to-thai-factory.html

    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 http://www.abc.net.au/news/2015-02-26/scombroid-fish-poisoning-linked-to-sydney-cafe-tuna/6263120

    Australian Food News, 2015. Canned Tuna Food Safety Scare Linked to Thai Factory. Retrieved from http://ausfoodnews.com.au/2015/03/11/canned-tuna-food-safety-scare-linked-to-thai-factory.html

    Canadian Food Inspection Agency, 2012. Food Safety Facts on Scombroid Poisoning. Retrieved from http://www.inspection.gc.ca/food/information-for-consumers/fact-sheets/food-poisoning/scombroid/eng/1332280657698/1332280735024

    Daily Mail Online, 2014. Australian Mother and Daughter Who Died in Bali Hotel Room Victims of Rare Fish Poison. Retrieved from http://www.dailymail.co.uk/news/article-2551853/Australian-mother-daughter-died-Bali-hotel-room-victims-RARE-fish-poison-combined-asthma.html

    Food Standards Australia New Zealand, 2015. Histamine (Scombroid) Fish Poisoning. Retrieved from http://www.foodstandards.gov.au/consumer/safety/Pages/Histamine-(Scombroid)-fish-poisoning.aspx

    New South Wales Food Authority, 2015. Update: NSW Food Authority Investigation into Scombroid at Sydney Café. Retrieved from http://www.foodauthority.nsw.gov.au/news/media-releases/mr-26-Feb-15-scobroid-sydney-cafe#.Vk_Ii0ujZ4U

    • 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.

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

    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). http://www.foodqualitynews.com/Food-Outbreaks/Denmark-investigates-four-Listeria-cases-linked-to-fish-producer

    Denmark investigates new Listeria outbreak. (May 2015). http://www.foodqualitynews.com/Food-Outbreaks/Listeria-sickens-five-and-a-factor-in-two-deaths


    Joint FAO/WHO Activities on Risk Assessment of Microbiological Hazards in Foods. Case Study: Listeria monocytogenes in Smoked Fish (including digram). Retrieved from http://www.fao.org/fileadmin/templates/agns/pdf/jemra/Listeria.pdf

    Report of the FAO Expert Consultation on the Trade Impact of Listeria in Fish. Retrieved from http://www.fao.org/docrep/003/x3018e/x3018e05.htm

    Center for Disease Control and Prevention. Whole genome sequencing. Retrieved from http://www.cdc.gov/listeria/pdf/whole-genome-sequencing-and-listeria-508c.pdf

    Center for Disease Control and Prevention. Tips for preventing Listeria poisoning. Retrieved from http://www.cdc.gov/ncezid/dfwed/pdfs/tips-preventing-listeria-508c.pdf

    Image retrieved from http://www.rivertea.com/blog/7-healthy-breakfast-recipes-for-every-day-of-the-week/

    • 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: http://foodsafety.wisc.edu/assets/pdf_Files/smokingyourcatch.pdf). 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, seafood, 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 (http://www.fda.gov/downloads/Food/GuidanceRegulation/RetailFoodProtection/FoodCode/UCM374510.pdf), 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, seafood,   

    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 http://www.foodsafetynews.com/2013/11/imports-and-exports-how-safe-is-seafood-from-foreign-sources/#.ViQNtyBViko
    • 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 http://www.cancer.gov/about-cancer/causes-prevention/risk/substances/formaldehyde/formaldehyde-fact-sheet

    • 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.

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