Category Archives: Week 7

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

Posted on November 20, 2015 by Ya Gao | 9 comments

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:
http://www.news.com.au/national/bali-deaths-of-noelene-and-yvana-bischoff-from-fish-poisoning-impossible-to-predict/story-e6frfkp9-1226818860731

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

9 Comments

Posted in Week 7

Tagged Australia, food safety, Oceania, Scombroid poisoning, seafood, seafood toxin

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

Posted on November 20, 2015 by Stephanie Chen | 6 comments

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

References:

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/

6 Comments

Posted in Week 7

Tagged Europe, food safety, Listeria, Listeria monocytogenes, seafood

Salmonella: in Frozen Raw Tuna?

Posted on November 19, 2015 by WinnieLiao | 14 comments

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:

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

And finally… Questions for you!

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

Salmonella in raw tuna articles:

http://www.foodpoisonjournal.com/foodborne-illness-outbreaks/salmonella-sushi-outbreak-update-62-sick-in-11-states/#.VkooIK6rSfV

http://www.foodsafetynews.com/2015/04/25-salmonella-cases-possibly-linked-to-raw-tuna-consumed-in-southern-california/#.VkoeCq6rSfU

http://bigmedicine.ca/wordpress/tag/salmonella-paratyphi-b-variant-l-tartrate/#sthash.VN7LcdMj.dpbs

FYI… Check it out! (References:)

Epidemiology of Seafood-associated infections in United States:

http://cmr.asm.org/content/23/2/399.full

Facts on Seafood safety:

http://seafoodhealthfacts.org/seafood_safety/practitioners/microbes.php

Salmonella Q&A:

http://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/foodborne-illness-and-disease/salmonella-questions-and-answers/

WHO document on Typhoid Fever: