Fw: [BITES-L] bites Oct. 6/10
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bites Oct. 6/10
Listeria in BC smoked salmon product; Kevin Allen speaks again
CANADA: Listeria on smoked salmon triggers investigation
US: In-demand fish: Making sure they're always safe to eat
NEW YORK: Increase in gastrointestinal illness
UK: Salmonella: Norfolk farmer calls for new legislation
FDA issues regulatory science report
Many pigs get contaminated with MRSA in the slaughterhouse
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Listeria in BC smoked salmon product; Kevin Allen speaks again
06.oct.10
barfblog
Doug Powell
http://www.barfblog.com/blog/144414/10/10/06/listeria-bc-smoked-salmon-product-kevin-allen-speaks-again
Hockey goon and University of British Columbia by food microbiologist Kevin Allen found some listeria in samples of smoked salmon and said,
"A healthy adult … likely could consume it with no consequence. However, if I was going to feed that to my daughter or son, the answer is no, I wouldn't."
And yes, kids eat smoked salmon. Almost-2-year-old daughter Sorenne especially likes brie cheese and smoked turkey breast, along with pickles and olives. Goofy kid (that's in a loving way).
CBC News reports that traces of the bacteria Listeria have been detected in samples of smoked salmon bought at a Vancouver retailer.
Two contaminated samples — including one containing the potentially fatal strain Listeria monocytogenes — were found in chunks of smoked salmon, called salmon nuggets, purchased at Longliner Seafoods at the Granville Island Public Market.
A total of 53 samples of delicatessen meat and ready-to-eat seafood from nine stores around Vancouver were tested by Dr. Allen.
No Listeria bacteria were found in the deli meat .
The sample containing Listeria monocytogenes contained a concentration of bacteria that was below the federal threshold that would have necessitated a recall, but it is still a cause for concern, said Allen.
"It should definitely be ringing some alarm bells for these processors."
People with compromised immune systems, including pregnant women and the elderly, are especially vulnerable to listeriosis.
http://barfblog.foodsafety.ksu.edu/blog/143568/10/08/07/ready-eat-salads-new-pathogens-fuel-rise-contaminated-produce
http://www.cbc.ca/health/story/2010/10/05/bc-listeria-salmon-vancouver.html
CANADA: Listeria on smoked salmon triggers investigation
06.oct.10
CBC News
http://www.cbc.ca/canada/british-columbia/story/2010/10/06/bc-listeria-smoked-salmon-study.html
The B.C. Centre for Disease Control is looking into the results of a CBC News investigation that found a potentially dangerous strain of Listeria bacteria in smoked salmon at a popular Vancouver market.
Dr. Tom Kosatsky, the director of Environmental Health Services, said inspectors are trying to determine where the smoked salmon nuggets were produced, where the contamination took place and whether a recall is necessary.
"Where positive samples occur, there is concern, and there is action that takes place," said Kosatsky.
CBC News bought the salmon nuggets at Longliner Seafoods on Granville Island. The manager there said they were smoked at a facility in Maple Ridge.
The Listeria bacteria was detected when CBC News bought a selection of deli meats and smoked salmon from nine stores around Vancouver and had them tested at a food microbiology lab at UBC.
On Tuesday, CBC revealed there was no Listeria on the meats, but two smoked salmon samples had strains of the bacteria, including one sample that had the toxic Listeria monocytogenes strain.
The bacteria was detected at a level low enough it wouldn't trigger a recall in Canada, but some countries, such as the U.S., have zero tolerance for any detectable levels of Listeria.
The results of the CBC News investigation match the results of an unreleased study by the B.C. Centre for Disease Control that also found Listeria in smoked salmon from up to five producers in B.C.
Some salmon nuggets purchased in Vancouver in a CBC News investigation were found to contain Listeria bacteria. (CBC)
The study looked at 293 samples of ready-to-eat foods — including meat, dairy and fish — purchased in B.C. between August and October 2009.
It found potentially toxic Listeria bacteria in 18 per cent of ready-to-eat fish products tested in B.C. All of the contaminated fish was smoked salmon, the study found. It also concluded fish processing facilities need more scrutiny.
The results triggered at least one recall in November 2009, of Smoked Salmon Cream Cheese Log and Maple Salmon Nuggets from Classic Smokehouse Inc.
However, the full results and recommendations have not been released. The B.C. CDC told CBC News it plans to release the report once the B.C. government is finished reviewing it.
But Kostatsky said that since the study was completed, some action has been taken to remedy the problems it found, including cleanup operations at the five processing facilities that were contaminated.
Dominic Losito, the recently retired director of health protection for Vancouver Coastal Health, questions why the public wasn't immediately informed of the health risks.
"We have to be transparent with the public. We have to actually provide them with as much information as they can so they can make sound decisions," said Losito.
US: In-demand fish: Making sure they're always safe to eat
05.oct.10
USDA's Agricultural Research Service
http://www.ars.usda.gov/is/AR/archive/oct10/safe1010.htm
Popular fish like salmon, catfish, and tilapia are coming under the close scrutiny of Agricultural Research Service food-safety scientists Andy Hwang and Kathleen Rajkowski. They're discovering more about how to prevent foodborne pathogens from contaminating these and other delicious, good-for-you seafood. Both scientists are based at the ARS Eastern Regional Research Center in Wyndmoor, Pennsylvania.
Hwang, a food technologist, has completed a series of studies in which he's simulated—in his laboratory—commercial processes used today for preparing smoked salmon. A gourmet treat, smoked salmon is typically sold in vacuum packages that have a refrigerator shelf life of about 3 to 8 weeks, according to Hwang. Trouble is, pathogenic microbes like Listeria monocytogenes can live at refrigerated temperatures, so it's important to get rid of these harmful microbes before the product leaves the processing plant.
Smoked salmon, pricey and, when properly prepared, delicate in texture, is often served in thin slices with bagels and cream cheese or as an appetizer, stacked on toast-type crackers with red onion and a splash of lemon juice. Too, some sushi bars feature smoked salmon surrounded by sticky rice and snugly wrapped in seaweed.
Hwang is looking for ways that processors can protect the pleasing flavor and texture of smoked salmon while reducing or eliminating contamination by L. monocytogenes or other foodborne pathogens.
At the Smokehouse
Smoked salmon is typically prepared by using what's known as "wet brining" or "dry brining" to cure the raw fillets before smoking. Fish cured with a wet brine are soaked in a solution of water, salt, and sugar, which preserves the fish, helps it retain moisture, and enhances its flavor. The brine may also include spices or liquid smoke, like the kind home chefs use for a backyard barbeque.
With dry brining, the salt and other compounds are rubbed on the fillets and later rinsed off before the fish is smoked.
The smoking process takes place in special smoking ovens in which wood chips are burned to smoke the cured fillets. Most processors opt for cold smoking, which uses temperatures of 68˚F to 86˚F to smoke—but not cook—the fillets. Cold-smoking takes about 3 to 4 days.
Hot-smoking, a lesser-used option for salmon, uses temperatures of about 140˚F and takes about 6 to 10 hours. Hot-smoking cooks the fish, giving it a different taste and texture than cold-smoked fish.
Many Combinations Tested
In a series of experiments, Hwang and colleagues Shiowshuh Sheen and Vijay Juneja at Wyndmoor exposed cooked salmon samples, prepared with various concentrations of salt and smoke compound (from burning wood chips or liquid smoke), to midrange temperatures—between 104˚F and 131˚F. "The temperatures were higher than those used for cold-smoking but not quite as warm as hot-smoking," explains Hwang. "We wanted to provide a range of alternative smoking temperatures for processors to consider and to show them the level of Listeria inactivation they might be able to achieve at various temperatures and various combinations of salt and smoke compound."
The scientists cooked the fillets for the tests to kill any existing microbes before inoculating the fish with Listeria. Not surprisingly, smoking temperature was the single most important factor for inactivating the microbe. "Every 9˚F increase in temperature resulted in a 10-fold increase in rates of inactivation of the Listeria," Hwang reports.
The researchers used data from the study to create a new, first-of-its-kind formula, or mathematical model, for food processors and their food-safety consultants to use in choosing the optimal combination of temperature and concentrations of salt and smoke compound.
"Users can plug into the model the salt concentration, smoke-compound concentration, and smoking temperature of their choice to predict what effect this combination may have on Listeria levels," says Hwang. "Salt and smoke-compound concentrations and smoking temperature affect taste, texture, and other key qualities of the smoked fish, so processors often have their own unique combination of these three factors. We constructed the model to accommodate a wide range of choices."
The team's 2009 article in the Journal of Food Science has details.
Now, Hwang intends to test these laboratory findings at a smokehouse and monitor the safety of the smoked salmon as it makes its way through the distribution chain, from wholesaler to retailer to restaurant or home.
And as a followup to a preliminary study that he and Sheen described in another 2009 Journal of Food Science article, Hwang wants to discover more about the extent to which other microbes—benign or harmful—can colonize the fillets and help or hinder Listeria's survival.
Powerful Tactics That Don't Require Heat
Meanwhile, colleague Rajkowski, a food microbiologist, is determining how to prevent certain foodborne pathogens from contaminating fish fillets. She's using tilapia and catfish fillets for this research. "Even though foodborne illnesses are not commonly associated with either of these fish," says Rajkowski, "we chose them for our research because they are the two most commonly consumed kinds of fish fillets in the United States today."
Microbes that she's studying include not only Listeria but also Salmonella, Shigella, Staphylococcus, Pseudomonas, and Escherichia coli O157:H7.
In one study, Rajkowski is determining the correct cooking times and temperatures for packaged tilapia fillets. Instructions for cooking fillets are sometimes based on visual determination—what the fish looks like.
"Instructions might require you to know what the fillet looks like when it 'flakes easily with a fork,'" she says. "Not everyone knows what's meant by that. We want to provide science-based cooking instructions that are precise and easier for everyone, even beginning cooks, to follow."
Rajkowski is continuing research on heat-free ways to reduce levels of harmful microbes. Overheating can easily ruin the taste and texture of fish.
In an early experiment with both frozen and thawed tilapia and catfish fillets, Rajkowski artificially inoculated the fillets with L. monocytogenes and then determined the amount of ionizing radiation needed to reduce the pathogen's population by 90 percent. The dosages required to achieve that level of safety were nearly the same for both kinds of fish, Rajkowski found. Published in the Journal of Food Protection in 2008, the study was the first to identify the dosages needed to effectively reduce Listeria in these popular fish products. Her results were similar to those that reduce Listeria in ground beef.
Rajkowski is also testing the effects of ultraviolet (UV) light in combating another pathogen, Shigella sonnei. Like Listeria, Shigella can cause gastrointestinal illness. For one investigation, Rajkowski applied a solution of S. sonnei to the surface of frozen tilapia and then exposed the samples to UV light. The treatment resulted in a 99-percent reduction of the pathogen. In contrast, tests with small samples of fresh tilapia showed that the UV treatment did not kill the pathogen. But exposing the fillets to pulsating beams of high-intensity UV light reduced the pathogen by 99 percent. Rajkowski documented the study in 2007 in Ice World Journal.
Fish that Hwang and Rajkowski are investigating are a good, low-fat source of high-quality protein. That's reason enough to make sure these fish, and others from farm and sea, remain pathogen-free and safe for us to eat.—By Marcia Wood, Agricultural Research Service Information Staff.
This research supports the USDA priority of ensuring food safety and is part of Food Safety, an ARS national program (#108) described at www.nps.ars.usda.gov.
Cheng-An (Andy) Hwang and Kathleen Rajkowski are with the USDA-ARS Eastern Regional Research Center, 600 E. Mermaid Ln., Wyndmoor, PA 19038; (215) 233-6416 (Hwang), (215) 233-6440 (Rajkowski).
"In-Demand Fish: Making Sure They're Always Safe To Eat" was published in the October 2010 issue of Agricultural Research magazine.
NEW YORK: Increase in gastrointestinal illness
05.oct.10
Onondaga County Health Department
http://www.ongov.net/health/news/index.html
Cynthia B. Morrow, MD, MPH Commissioner of Health announced today that over the past several days the Onondaga County Health Department and the New York State Department of Health have been investigating laboratory confirmed cases of Campylobacter, a bacterial infection that can cause diarrhea, abdominal cramps, and fever. At least 7 people in Central New York became ill with this infection after eating at Hinerwadel's on September 15, 2010. The incubation period for this infection is usually 2-5 days however, can be as long as 10 days. People who have campylobacteriosis can have symptoms for up to two weeks. Morrow anticipates that the number of ill people associated with this outbreak will grow.
Morrow requests anyone who ate at this facility on or after September 15 and who became ill to contact the Health Department at 435-6607. The public is advised to seek treatment from their health care provider if they are experiencing persistent symptoms of gastrointestinal illness.
The Health Department is investigating the source of this infection and will update the public as more information becomes available. At this time, there is no indication of improper food handling practice at the facility.
UK: Salmonella: Norfolk farmer calls for new legislation
05.oct.10
BBC
http://news.bbc.co.uk/local/norfolk/hi/people_and_places/nature/newsid_9064000/9064012.stm
A Norfolk duck egg farmer is calling for tighter legislation to reduce the risk of salmonella in duck products.
While all hens are currently vaccinated against the disease, ducks are not.
"We're supplying a food product and I think therefore that there should be legislation," said Melandy Daniels, Watercress Lane Duck Eggs, Dereham.
Duck eggs and duck products were implicated in a national outbreak of salmonella by the Health Protection Agency in September 2010.
Watercress Lane Duck Eggs currently vaccinate all their ducks against the disease.
FDA issues regulatory science report
06.oct.10
FDA
http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm228482.htm
The U.S. Food and Drug Administration today unveiled a report outlining the agency's plans to advance regulatory science through its Regulatory Science Initiative. Regulatory science is the science of developing new tools, standards and approaches for assessing the safety, efficacy, quality and performance of FDA-regulated products. The report provides examples of current FDA activities in regulatory science and also considers how advancements in the field can help deliver better, safer, more innovative products to Americans in seven different public health areas. Copies of the report will be released at the National Press Club in Washington, D.C., when FDA Commissioner Margaret A. Hamburg M.D. speaks to a club luncheon.
Her address will begin at 1 p.m. and will be broadcast live by C-SPAN. For more information:
Advancing Regulatory Science for Public Health
V. Protecting the Food Supply
06.oct.10
FDA
http://www.fda.gov/ScienceResearch/SpecialTopics/RegulatoryScience/ucm228211.htm
Food safety is one of FDA's most critical public health priorities. As in other areas, the effectiveness of FDA's food safety program depends on the strength and capacity of the science underlying it. Although much research on food safety is carried out at universities and in private industry, FDA's regulatory role creates unique scientific and technological needs and opportunities that can be met only by a robust regulatory science program.
In 2007, FDA's Science Board warned that a lack of adequate scientific capacity and tools in FDA's Foods Program was limiting the agency's ability to protect the nation's food supply.
What has FDA done?
To meet the challenges of the 21st century food supply, including the dramatic increase in imported foods, FDA has increased its investment and sharpened its focus on the science needed to detect food safety breakdowns and to understand how they occur. Although the ultimate goal is to prevent food safety breaches from occurring in the first place, we need the tools to contain them effectively and efficiently if they do occur. As noted in the example below, these technologies are critical on an ongoing basis and in the event of natural disasters that affect the food supply.
• Development of new chemical tests to assess food safety in the Gulf of Mexico after the Deepwater Horizon Oil Spill The Deepwater Horizon disaster released in excess of 92 million gallons of oil into the Gulf of Mexico, resulting in devastating environmental damage and concerns about the safety of seafood caught in that area. FDA, in concert with state health authorities, was and continues to be responsible for ensuring the safety of seafood caught in the Gulf. This is accomplished through extensive sampling and testing of seafood harvested from the Gulf and sampled from seafood processing and distribution centers across the nation. At the outset of the spill, a chemical method for measuring for the presence of polycyclic aromatic hydrocarbons (PAH), which are found in significant amounts in crude oil and which contain a number of known carcinogens, was known but required extensive time and effort for sample processing and analysis. The FDA worked diligently to develop a rapid, highly sensitive chemical testing method and is now using this method to test seafood from the Gulf to ensure it is safe for consumption.
What can FDA do with increased investment in regulatory science?
A major focus of FDA's interest in regulatory science is the development of more rapid and practical methods for detecting microbial pathogens in food and equipping FDA's labs to test multiple food samples for contaminants simultaneously. FDA must also provide scientific leadership to enhance understanding of the causes of food-borne illnesses so that interventions can be designed and implemented to effectively and feasibly reduce risk.
A number of additional opportunities exist to advance regulatory science to improve food safety:
• Developing effective tools and strategies for sampling, testing and analysis Tools for the laboratory and for field investigators, such as hand-held devices, are being developed and evaluated to enhance analytical capacity and capability for detecting pathogens of major public health concern such as E. coli O157:H7, Salmonella, and Listeria.
• Tracking Salmonella in the food supply Salmonella is the leading bacterial cause of food-borne illness in the United States and can originate from many different animal sources. Rapid methods are being developed to speed the detection and investigations of outbreaks. We are using cutting-edge technology to investigate and identify animal sources for human Salmonella infections, as well as antimicrobial resistance and virulence determinants.
• Preventing microbiological hazards FDA is studying the prevalence and behavior of microbiological hazards in foods to provide the data needed to assess risks, determine the effectiveness of potential control strategies, establish food safety standards and provide practical food safety guidance to industry.
• Responding to food-borne illness Identifying virulence factors, epidemiological markers and other determinants that influence the ability of pathogenic microorganisms to use foods as vehicles for disease transmission will help enhance epidemiological investigations, intervene earlier in an outbreak and more accurately attribute illness to a product.
• Controlling toxins FDA is attempting to identify the effect of food production, processing, preparation and use practices on the generation of toxic contaminants, inactivation of naturally occurring toxins and nutrient content.
• Monitoring antibiotic resistance in food-borne pathogens Ongoing monitoring of antibiotic resistance is central to FDA programs to limit the spread of antimicrobial-resistant food-borne pathogens. The National Antimicrobial Resistance Monitoring System (NARMS) monitors trends in antibiotic resistance among food-borne pathogens from animals (conducted by the U.S. Department of Agriculture), humans (conducted by the CDC) and retail meats (conducted by FDA). Since its inception in 1996, more than 210,000 test results have been added to the NARMS database. All NARMS recovered Salmonella and Campylobacter isolates are compared to human isolates in CDC's PulseNet database. Expansion of this effort could provide additional critical information about the effect of antibiotic use in animals on resistance in human bacterial strains.
With continued and enhanced efforts in these and other areas of regulatory science, FDA can help provide the knowledge, tools, and scientific leadership needed to improve food safety and protect public health.
Many pigs get contaminated with MRSA in the slaughterhouse
06.oct.10
VetsWeb
http://www.vetsweb.com/news/many-pigs-get-contaminated-with-mrsa-in-the-slaughterhouse-1499.html
One in ten pigs gets the MRSA bacterium in livestock transport trucks, while sixty percent of pigs in slaughterhouses have the bacterium. Wageningen University veterinary researcher Els Broens finds this 'very disconcerting'.
Broens trailed 117 pigs from the farm to the slaughterhouse. She inspected them for the presence of MRSA before and after the journey to the slaughterhouse, and after they were sedated before the slaughter. While none of the pigs had MRSA before the journey, 10 percent of them tested MRSA-positive afterwards. After the sedation in the slaughterhouse, the bacterium was found in sixty percent of the pigs. This research work was carried out jointly by Wageningen UR, the National Institute for Public Health and the Environment (RIVM) and the Animal Health Service (GD).
Waiting area The pigs en route and in the slaughterhouse were not infected with MRSA, implies Broens. 'The resistant bacterium was lodged in their noses but infection did not take place.' The livestock trucks were cleaned after every journey. The animal waiting areas in the slaughterhouse were cleaned daily, but not throughout the day. Therefore, one batch of pigs could have infected another. In contaminated livestock trucks, twenty percent of the pigs became contracted the bacterium. In trucks which were not contaminated, no such cases occurred.
'The waiting area for the pigs was hose-cleaned, but not disinfected, daily', says Broens. 'Throughout the day, droppings, bacteria and viruses were accumulated. The pigs spent a few hours, or even more sometimes, in this area. Therefore, they ran the risk of getting infected by MRSA. But it was extraordinary that the spread of MRSA happened so quickly among the pigs in the waiting area.'
Resistant The Methicillin-resistant Staphytococcus aureus (MRSA) bacterium is resistant against various types of antibiotics also used in human healthcare. Humans and animals can get infected by MRSA when they have problems from an underlying disease, open wounds and skin disorders. Using the usual antibiotics to fight the infection often does not work.
The MRSA bacterium does not cause food poisoning, unlike, for example, the salmonella bacterium. But transport and slaughterhouse workers run a big risk of getting the MRSA bacterium. They can infect other people in turn, says Broens.
Disinfect Drastic measures to cut down infections by the MRSA bacterium in slaughterhouses - such as disinfecting the waiting area after every batch of pigs - are almost impossible in practice, says Broens. 'I feel that the problem has to be tackled at its source: the farm.' The MRSA bacterium is present in almost three quarters of the farms in the pig sector, as shown by earlier research.
Broens, attached to the Quantitative Veterinary Epidemiology chair group, has published her research proceedings in The Veterinary Journal this month. She hopes to obtain her PhD next year in this research area
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