Salmonella Blog - Surveillance & analysis on salmonella news & outbreaks

For food and drink companies a health scare can be extremely damaging, as Cadbury Schweppes has found out to its cost over the past month following the recall of a million chocolate bars due to salmonella concerns.

The estimated cost of the recall was 5 million pounds, although the longer-term damage to its brand could end up costing significantly more. The polling company YouGov recently revealed its BrandIndex product, which tracks consumer perception of various top brands, had detected a swift reversal in perception towards Cadbury.

Investors who have, by and large, stuck by the company will be looking for reassurance from its management at its interim results on Wednesday and for an update on sales in the five weeks since the scare emerged. Cadbury shares, which hit a five-year high of 591p earlier this year, briefly dipped below the 500p level but have since consolidated around the 510p level.

Food editor J Scott Wilson walked readers through a typical grilling experience and took a look at where the danger lies and some simple ways to avoid it:

Temperature Control

By far the biggest culprit when it comes to any sort of outdoor cooking and eating is lack of attention to food temperature. Basically, your mission is to keep your food out of the "bacterial danger zone" of between 45 and 140 degrees Fahrenheit. Within that range, bacteria can grow at increased rates and increase the risk of food-borne illnesses dramatically. In just three to four hours, a food such as potato salad can become a big bowl of unpleasant bathroom adventures for you and your guests.

The same holds true for meat you'll be grilling. The time to put your meat out next to the grill is NOT when you start lighting the charcoal. Yes, beef which has been allowed to rise to room temperature grills better, but that doesn't mean you should set your steaks out to get a tan while your briquets get properly lit.

The most dangerous meat when it comes to temperature sensitivity is chicken. Chicken does not need to warm before cooking, and needs to go from fridge to grill pretty quickly. If you've got the whole clan over for a big cookout and you're doing multiple batches of chicken, make sure each batch is either eaten or put into a warm oven until mealtime. What I like to do, if grilling leg quarters, is to pull the first batch slightly underdone and put it in a very low (200 degrees) oven while I cook the next batch. That way, the first batch won't be cooked to dust when the last one is finished.

I shouldn't need to tell you how fragile all types of seafood are when it comes to temperature. Fish and seafood of all types should go straight from refrigerator to grill, with a brief stop at the cutting board for seasoning if necessary.

Tools

Cross-contamination occurs when cooked food comes in contact with raw food, either directly or by the use of improperly cleaned tools.

There are a few easy ways to guard against cross-contamination. They may add a step or two to your cooking process here and there but the lack of bathroom/hospital/being dead time makes up for it.

Cutting boards may be fantastic for chopping veggies for a salad, but lay a chicken on it and you're begging for trouble. Meat juices permeate wood and lodge in all the little nooks and crannies. They are almost impossible to clean completely, and even a soaking in bleach water can leave organic matter that will breed bad bugs. Stick to a good, cheap plastic cutting board for your meat. I like having two: one for raw and one for cooked.

Do be careful about putting rocket-hot hunks of meat down on your plastic board. A cooling session on a plate can keep your steak from getting hydrocarbon from melted plastic.

Just as I've got two cutting boards, I like to duplicate everything else, within reason. Two sets of spring-loaded tongs are a must, and separate platters for raw and cooked.

For really expensive tools like a chef's knife, a good hot-water washing followed by passing through a diluted bleach solution will make it safe. In the restaurant business, hand dishwashing takes place at a three-compartment sink: wash, rinse and sanitizing. You can get the same effect by filling a pitcher or tub with a bleach solution and giving each tool that's moving from raw to cooked a 10-second soak.

Zone Defense

The basic idea here is to keep your raw food away from your cooked food. Thus, you need to pay careful attention to your zones. No tool from the raw "zone" goes into the cooked "zone" unless it's properly sanitized and vice versa. I've had friends who even bought different color utensils to help them keep track of which was which, or put bits of colored tape on handles.

Leftovers In Peril

And, finally, let's talk leftovers. The temperature danger zone also happens to be the one in which most food is edible. So you get done eating, get up from the table and play a brisk game of post-meal football ... or grab a brisk post-meal nap. And your food sits. And sits. And bacteria find it, and it is good, and they are fruitful and multiply.

Next thing you know, that leftover steak you were saving for a wicked good steak sandwich is teeming with more microorganisms than a college dorm room.

Even if all you do is throw some plastic wrap over the serving platter and toss it in the refrigerator, getting your leftovers under refrigeration immediately after the meal will ensure safe midnight snacking and day-after sandwich creation.

Eating ice cream to beat the summer heat is one of America's favorite pastimes. Homemade ice cream can be a special treat. While commercially manufactured ice cream is typically made with pasteurized eggs or egg products, recipes for homemade ice cream often use raw eggs in the base mixture.

Lynn Little has some suggestions for safe alternatives to using raw eggs in your homemade ice cream:

• Find a recipe that is eggless. An easy one calls for 2 cups milk, 1 cup sugar, 2 cups whipping cream or half-and-half, and 2 teaspoons vanilla. Combine and stir until sugar is dissolved, then pour into a 1-gallon ice cream freezer and freeze according to manufacturer's directions.
• Use pasteurized shell eggs or pasteurized egg substitutes in recipes calling for raw eggs. These can be found in the dairy case near the regular eggs. The FDA requires that pasteurized shell eggs be individually marked or specially packaged to prevent intermingling with unpasteurized eggs. Although pasteurized eggs might cost a few cents more, the pasteurization process destroys salmonella bacteria.
• Use a recipe that contains a cooked custard base. The custard base must reach 160 degrees, measured with a food thermometer, to kill salmonella bacteria. This is also the point at which the mixture will coat a metal spoon. Resist the temptation to taste-test it during preparation when the custard isn't fully cooked. After cooking, chill the custard thoroughly before freezing. A recipe for homemade ice cream using a cooked egg base is available on the American Egg Board's Web site, along with recipes for other foods traditionally made with raw or undercooked eggs, such as mayonnaise, Caesar salad dressing and eggnog.
• Even when using pasteurized eggs, the FDA and the USDA advise consumers to start with a cooked base for optimal safety, especially if serving people at high risk for foodborne illness. Additionally, it's important to only used pasteurized milk and cream products in making homemade ice cream.

New research has shown that salmonella was found in 1% of raw meat tested at laboratories reporting to the Department of Agriculture over a three-year period. Laboratories submit a monthly report of all tests carried out, together with reports of salmonella bacteria, to the Central Veterinary Research Laboratory.

The percentage of raw meat samples contaminated with salmonella has decreased over the three-year period from 1.2% to 0.9%.

The bacteria was found most commonly in turkey and chicken meats at 3.1% and 2.8% respectively, followed by pork at 2.1%.

Two weeks ago, the state Department of Public Health determined a fifth-grade science experiment involving the dissection of owl pellets was responsible for a salmonella outbreak, in which 28 students were confirmed to have the bacterial infections.

In all, at least 50 students came down with related symptoms.

More than 40 parents and residents have issued a letter, stating that school officials ignored basic sanitary precautions and jeopardized the health of students and parents. The letter alleges children were told they did not need to wash their hands or sanitize their desks after they conducted experiments; students were permitted to eat snacks at their desks after the experiments; and one student who brought in latex gloves for the experiment was told she could not wear them.

Donna Rheaume, a DPH spokesman, said her department would issue additional guidelines in coming months when a full report on the outbreak is released.

The Canadian Food Inspection Agency says that the two largest poultry exporters in British Columbia faked salmonella tests on chicken bound for South Africa.

Superior Poultry Processors Ltd. of Coquitlam and Hallmark Poultry Processors Ltd. of Vancouver have been fined $100,000 on four counts of violating the Meat Inspection Act.

Export sales manager Bruce Arabsky has plead guilty to submitting 31 falsified certificates of analysis between April 10, 2003, and Jan. 25, 2005 for poultry being exported to South Africa. Arabsky has been responsible for all exports of poultry products by Superior and Hallmark since 1992. He is also a director of the Canadian Poultry and Egg Processors Council and served as a spokesperson for the B.C. poultry processing industry during a 2004 bird flu outbreak that forced a widespread slaughter of chickens and saw some countries impose temporary bans on imports of Canadian birds.

The certificates, which are required by the CFIA before exports are authorized, falsely stated that the poultry products had been tested for salmonella enteriditis and salmonella typhimurium.

The fakery was discovered when a CFIAS inspector checked with the laboratory listed on the certificates and was told it has performed no such tests since 2002.

Scientists from around the world have met in Germany this week to set research priorities on a broad range of zoonoses -- food borne diseases that are transmissible from animals to humans. Scientists from the EU zoonoses network Med-Vet-Net and experts from the American Food Safety Research Consortium met this week in Berlin to identify the main risks to health from zoonotic pathogens.

The risk of pathogens traveling across borders has become evident during the recent outbreak of avian influenza worldwide. However diseases such as Salmonella, Campylobacter and E.coli have a higher rate of incidence and much larger impact on consumer health and the economy. In Germany alone, 52,000 cases of Salmonellosis were reported last year. Across the EU, Campylobacteriosis cases are on the rise, making it the most common food borne disease in Europe.

Currently, the US is implementing tougher testing standards to stem a spike in Salmonella infections at processing plants. EU regulatory authorities in member states have also been increasing their regulation of the industry due to increases in Campylobacteriosis.

It is estimated that in the European Union alone, food born pathogens generate medical costs of more than $6 billion a year and are set to rise.

The conference, held at the Federal Institute for Risk Assessment's in Berlin, is also being attended by professionals from Australia, New Zealand and Canada.

The June issue of the Journal of Food Protection included an article by Laura MacDougall in regards to a case control investigation of frozen chicken nuggets and strips. MacDougall is with Epidemiology Services at the British Columbia Centre for Disease Control in Vancouver. The investigation was initiated due to the discovery of Salmonella enterica var. Heidelberg in those food products.

Most frozen nuggets and strips are raw; however, par-frying lends a cooked appearance. As such, suitable food preparation precautions might not be undertaken by consumers. One-third of consumers interviewed considered frozen nuggets and strips to be precooked, and one quarter used the microwave, an ill-advised cooking method. Consumer misconceptions like these contributed to the risk of infection.

The odds of infection were 11 times higher in individuals who had consumed frozen processed chicken nuggets and strips.

The article recommends clearer labels identifying nuggets and strips as raw poultry are needed.

Health officials have warned consumers to make sure they fully cook frozen meat and poultry products, in the wake of several Salmonella infections linked to frozen chicken entrees sold in Minnesota and Michigan. The entrees implicated in Minnesota were sold at Cub Foods stores under the Cub name.

Four cases of salmonellosis have been linked with frozen, prebrowned stuffed chicken entrees in Minnesota, the Minnesota Department of Health reported in a news release yesterday.

"While these products are breaded and prebrowned, and so may appear to be precooked, they are in fact still raw and need to be prepared accordingly," Minnesota State Epidemiologist Dr. Harrry Hull said in the news release. An FSIS statement said consumers heated the products in microwave ovens and might not have realized they contained raw chicken. Such products should be cooked to an internal temperature of at least 165 degrees Fahrenheit.

Cub voluntarily pulled the implicated product lots from store shelves, the MDH said. Cub officials told MDH they would redesign the labels before putting the products back on shelves.

Journal of Food Protection Volume 69, Number 7 pp. 1653-1661(9)
Kim, H.J.; Park, S.H.; Lee, T.H.; Nahm, B.H.; Chung, Y.H.; Seo, K.H.; Kim, H.Y.
http://www.foodprotection.org/QuickLinks.htm

Salmonella enterica serovar Typhimurium is a major foodborne pathogen throughout the world. Until now, the specific target genes for the detection and identification of serovar Typhimurium have not been developed. To determine the specific probes for serovar Typhimurium, the genes of serovar Typhimurium LT2 that were expected to be unique were selected with the BLAST (Basic Local Alignment Search Tool) program within GenBank. The selected genes were compared with 11 genomic sequences of various Salmonella serovars by BLAST. Of these selected genes, 10 were expected to be specific to serovar Typhimurium and were not related to virulence factor genes of Salmonella pathogenicity island or to genes of the O and H antigens of Salmonella. Primers for the 10 selected genes were constructed, and PCRs were evaluated with various genomic DNAs of Salmonella and non-Salmonella strains for the specific identification of Salmonella serovar Typhimurium.

Among all the primer sets for the 10 genes, STM4497 showed the highest degree of specificity to serovar Typhimurium. In this study, a specific primer set for Salmonella serovar Typhimurium was developed on the basis of the comparison of genomic sequences between Salmonella serovars and was validated with PCR. This method of comparative genomics to select target genes or sequences can be applied to the specific detection of microorganisms.

Gillian Green, a registered dietitian with the Dominion grocery store on Blackmarsh Road in St. John's, says food poisoning - or food-borne illnesses as it is often called - is more common than people might think.

"People may not realize they have food poisoning because the symptoms are very similar to that of the flu," she said.

Health Canada estimates there are between 11 million and 13 million cases of food-related illnesses in this country every year, with the annual cost related to these illnesses and related deaths running between $12 billion-$14 billion.

In order to prevent food poisoning, Green advises that leftover foods be stored within two hours of cooking and should never be kept longer than two or three days. Hot items should be cooled at room temperature for about 30 minutes prior to being refrigerated, she said.

In addition, frozen foods should never be defrosted on the countertop, but rather in the refrigerator, under cold running water or in the microwave. If food is defrosted in the microwave, it should be cooked immediately after.

Figures provided exclusively to the newspaper by Brand Index, part of the polling company YouGov, show that Cadbury's reputation has plummeted since it was forced to recall millions of chocolate bars after finding traces of salmonella at its factory in Herefordshire.

Cadbury has said it will cost 5 million pounds to recall all its potentially contaminated products, but has so far failed to quantify the impact on sales of its chocolate products such as Dairy Milk and Flake bars.

Chocolate sales in the UK were already falling before the Cadbury scare. According to AC Nielson, the market research company, total UK sales dropped by 5% in the four weeks to June 17.

Analysts have estimated that the financial cost to Cadbury in terms of lost sales could reach 30 million pounds.
 

Cadbury, once a brand that conjured up comfortable images of tasty confectionery fulfilment, has lost the confidence of consumers following a salmonella scare at one of the company's plants.

Stephan Shakespeare, the joint chief executive of Brand Index, said, "The loss of confidence in Cadbury is the greatest we have seen since we started Brand Index nine months ago. The issue has gone right into the core of the public consciousness."

Brand Index, which monitors the reputation of hundreds of organisations on a daily basis, compiled a "brand score" for Cadbury based on the responses of those polled to a number of questions about how the company is perceived. In the days before the salmonella scare broke, Cadbury enjoyed a score of 44. But that had fallen to just 22 by last Sunday.

However, the Brand Index figures show that Cadbury's reputation has enjoyed a slight recovery in the past few days as publicity surrounding the salmonella scare dropped away.

Cadbury has said it will cost 5 million pounds to recall all its potentially contaminated products but has so far failed to quantify the impact on sales of its chocolate products such as Dairy Milk and Flake bars.

A month after a science project made 28 students ill with salmonella at Jefferson Elementary School, several parents are accusing the school district of not being aggressive enough in dealing with the outbreak.

In a sternly worded letter dated July 10, more than 40 parents and residents -- including some prominent town officials -- charge that school officials ignored basic sanitary precautions, jeopardizing the health of students and parents.

Last week, the state Department of Public Health determined a fifth-grade science experiment involving the dissection of owl pellets in May was responsible for the outbreak, in which 28 students were confirmed to have the bacterial infections. In all, at least 50 students came down with related symptoms.

The letter alleges children were told they did not need to wash their hands or sanitize their desks after they conducted experiments; students were permitted to eat snacks at their desks after the experiments; and one student who brought in latex gloves for the experiment was told she could not wear them.
 

A combination of specific packaging films, cleaning chemicals and modified atmospheres can lengthen the shelf life of fruit and vegetable varieties, according to studies by the USDA.

The use of special films combined with modified atmosphere packaging method and cleaning chemicals has long been known to improve shelf life. However, the study by the USDA's research service provides smaller processors access to publicly-funded research that can help them compete with the big players in the market.

Fresh-cut fruit and vegetable varieties are still alive, and each respires at its own unique rate. Therefore, a film's permeability and the amount of oxygen initially infused into a package are key to extending its shelf life. Hundreds of different types of films for packaging fruit and vegtables currently exist on the market. Each type has its own oxygen transmission rate, which allows sliced produce to continue breathing throughout storage and distribution.

If a film's oxygen transmission rate is too high for the variety it's wrapping, the product inside will brown. If it's too low, the product will prematurely decay.

More recent studies have shown that a newer wash treatment eliminated two pathogens--Listeria and Salmonella--on apple slices.

Kenneth Gross, a plant physiologist who heads the PQSL. "We're conducting research to help find ways to widen the variety of offerings that stay fresh to the last bite."

A woman is considering taking legal action if tests prove she contracted salmonella poisoning after eating a Cadbury's chocolate bar.

Catherine Henderson, 62, of County Antrim, North Ireland, spent five days in hospital. Her lawyers said tests found she had the same strain of the bug. In a statement, Mrs Henderson's solicitors Irwin Mitchell said she was rushed to hospital after having trouble breathing and was kept on an isolation ward for five days.

Mrs Henderson said she had eaten a Cadbury's caramel bar.

A spokesman for legal firm Irwin Mitchell, David Standard, said: "We have strong medical evidence that Mrs Henderson's illness is linked to the eating chocolate. "We are carrying out further medical test which should prove this link."

A Cadbury's spokesman said: "Whilst we continue to work with the Food Standards Agency and local authorities, no link has been found between any incident of salmonella illness and our products. Minute traces of salmonella were found in a very few of hundreds of samples tested which we believe was well below the levels that would cause illness."

Authorities are warning residents to take special care in preparing and handling food, as temperatures rise above 40C during the summer. The warning comes as doctors report an increase in food poisoning cases in the UAE, a seasonal trend associated with summer.

An official at the infectious diseases department with the Dubai Department of Health and Medical Services told Gulf News that the summer season always saw an increase of food poisoning cases due to various ways. "There are many factors influencing bacteria and toxins in food during the summer," he said.

Dr Juma Bilal Fairuz, director of preventive medicine at the Health Ministry, told Gulf News that washing one's hands was the most important step in preventing food poisoning. He said the warm and humid conditions during summer allowed more bacteria to survive longer on surfaces and hands.

"Do it while preparing, before eating and after eating food. Even if you use a fork, spoon or knife, it is better to wash your hands in case you touch the food," he said. "And wash your hands after going to the toilet, preferably with soap."

Do's

• Wash your hands, especially after using the bathroom and before cooking and eating.
• Wash surfaces when cooking
• Keep raw food separate from cooked food
• Thaw and marinate foods in the refrigerator; if in a hurry, thaw foods under cool running water
• Use foods within expiration dates
• Cook foods until they reach the right temperature: meats and seafood to at least 63C, stuffed fish and ground chicken to 74C, ground beef to 77C and whole poultry and pieces to 82C
• Cook eggs until the egg white and yolk are firm

Don'ts

• Leave cooked food out for more than two hours
• Store perishable foods, like eggs, in the door container
• Keep thawing and refreezing the same food, as each process increases contamination risk

Attorneys for Pennsylvania-based Sheetz convenience stores and scores of customers sickened during a salmonella outbreak two years ago have settled more than 80 lawsuits in recent weeks and agreed to delay a filing deadline in hopes that dozens of other claims might settle.

The outbreak began on July 1, 2004 and eventually more than 400 people became ill in Pennsylvania, Ohio, West Virginia and six other states. Federal investigators traced the tomatoes to a Florida packing house. The federal investigation absolved Altoona-based Sheetz Inc. and the tomato wholesaler, Coronet Foods Inc., of Wheeling, W.Va. But under Pennsylvania's strict liability laws, both can still be sued because they sold the tomatoes.

Coronet shut down in October 2004 and filed for bankruptcy shortly after a few lawsuits were filed by other attorneys. Seattle attorney William Marler said Coronet has $11 million dollars worth of insurance that also covers Sheetz, which Marler said is more than enough to cover all the legal claims.

Sheetz's insurance company and two that insure Coronet must still determine who will pay what share of the settlements. Besides Marler's cases, Sheetz has settled 600 claims out of court, ranging from people who got ill to customers who were simply concerned about becoming sick. Most of the 600 contacted the company through a toll-free hot line.

In a report, the group Food and Water Watch said USDA should publish on a quarterly basis figures for salmonella tests at the plants. At present, the agency releases a national average but does not list plants individually.

Wenonah Hauter, head of Food and Water Watch, said USDA ought to "routinely test all plants and disclose the results." They are suggesting that the Agriculture Department should seek legislation to allow it to shut down U.S. poultry processing plants that have too much salmonella bacteria in their product.

USDA began sampling for salmonella in the late 1990s but was barred by a 2001 U.S. district court ruling from withdrawing federal inspection from a plant if it failed to meet standards for controlling salmonella.

Bonnie Rose, a microbiologist with the Food Safety and Inspection Services division of the USDA, develops laboratory-testing methods for food-borne diseases like E. coli and salmonella.

Rose's work has centered on the development of laboratory testing methods for E. coli and salmonella. Her methodologies are now used worldwide as advanced detection practices for these food-borne pathogenic bacteria.

Last month, Rose, who grew up in Harrisonburg, was one of 12 recipients of the USDA's 2006 Unsung Hero Award. According to the USDA, the Unsung Hero designation is meant to "identify those employees who have been unusually dedicated and efficient and [have a] positive attitude."

Rose, now living in Laurel, Md., has authored more than 90 scientific publications on food microbiology.

Dr Gary A. Kearney, Laboratory Liaison Manager with safefood, offers some tips on dealing with a food complaint, essentially advising on how to recognize when hygiene standards do not meet safety standards, when food isn't fit for consumption, who to complain to, and what to do if you believe you have suffered food poisoning.

Always be vigilant to ensure that the person preparing your food isn't handling raw meat, or fish, and then other prepared meals without hand washing. Cross contamination could result in a serious bout of food poisoning. Hand washing is absolutely key to alleviating the risk of food poisoning. Also ensure that:

• Hot food is piping hot
• Ready-to-eat food is NOT in contact with raw meats or fish
• Fridges are cold

When eating out in a restaurant, buying fresh food in a supermarket, or anywhere that food of any kind is sold, if you need to complain, start with the person serving you. If you don't feel satisfied with the response, ask to speak to a manager. If you have eaten food you did not prepare directly, which results in food poisoning, contact your doctor.

Make a note of when and where you purchased the suspect food, when you first fell ill and what the symptoms were. If you still have any of the suspect food, put it in a sealed container in either the fridge or freezer as appropriate. Try to keep any labels or any packaging associated with the food product. Also, contact your local environmental health officer who will investigate the issue. If other people report illness associated with similar products or premises, your report will highlight a potential food poisoning outbreak.

Painful stomach illnesses caused by eating contaminated bean sprouts could become a thing of the past, thanks to what Prof. Keith Warriner of the University of Guelph and four colleagues call a breakthrough in finding a safe, effective way to decontaminate seeds used to produce bean, alfalfa and other sprouts.

They've developed a sanitizer to kill pathogens such as salmonella and E. coli. It's made from the same chemical used in toothpaste and contact lens solutions.

Mung bean sprouts, often touted for their health benefits, were the culprit in an outbreak of food-related illness in Ontario last November when 600 people contracted salmonella. Public health scientists believe the seeds used for sprouting are the most likely source of contamination.

In research published Tuesday in the Journal of Food Protection, the team says adding an oxycholoro-based sanitizer called Germin-8-or to the steep water decontaminates sprout seeds as they germinate. Warriner said non-organic sprout producers currently treat seeds with bleach before the germination process, a method he said doesn't work consistently because bacteria can lodge in tiny seed cracks where bleach can't reach them.

A global patent has been submitted and the producers of the sanitizer are seeking regulatory approval and distributors in North America.

The salmonella food poisoning bug found in Cadbury chocolate may have contaminated up to 30 different brands, food safety officials have warned.

Safety tests are now being carried out on a wide range of bars after it emerged that the contamination, which was caused by a leaking pipe discovered earlier this year at a Cadbury plant, may have been far greater than first realised. More than one million Cadbury chocolate bars were withdrawn from sale 10 days ago after the firm admitted that chocolate "crumb" was contaminated with traces of salmonella montevideo, a rare strain of the bug, six months ago.

Health officials in Birmingham are now testing another 30 brands and the Food Standards Agency has warned that other types of Cadbury chocolate could be withdrawn.

Nine persons in the United States and Canada were infected with salmonella in 2004 and 2005 after handling pet treats made with beef or seafood, according to the CDC.

Six cases of salmonellosis occurred among people who became ill after handling pet treats produced by manufacturing plants in Washington state or British Columbia. Two other cases involved victims who handled pet dogs that were carriers of the salmonella bacteria.

The manufacturing plants that produced the salmonella-tainted pet snacks received frozen, raw beef parts from slaughterhouses in the United States and Canada. The Washington plant also received frozen, raw salmon.

“Animal-derived pet treats are often contaminated with salmonellae, and the dehydration procedure used to make pet treats might not be effective" at eliminating the potentially deadly bacteria, wrote Dr. Larry Crowe of the Calgary Health Region in Alberta, the study's lead investigator. In these cases, the authors said, the dehydration temperatures were not high enough to destroy bacteria that were present.

Stool cultures from the nine victims all showed evidence of infection with the Thompson strain of salmonella, which exactly matched bacteria from pet treats, pets and the manufacturing plants.

Although most Americans have no idea that handling pet snacks made of meat or seafood can make them vulnerable to salmonellosis, the issue has concerned public health officials since 1999. In that year, contaminated pig ear pet treats were confirmed as the source of salmonella infections in several Canadian provinces.

The CDC and the Public Health Agency of Canada advise pet owners to wash their hands with soap and water after handling animal-derived pet treats. They encourage people at high risk for salmonella infection, such as the elderly, the very young and the immune-compromised, not to touch pet treats.

In addition, they say manufacturers of pet snacks should thoroughly treat animal products to kill bacteria and should add pertinent product information to their labels.