Pet treat to reduce the risk

Lately there has been a run of pet treat recalls due to Salmonella contamination (with the latest one courtesy of "Diggin' Your Dog"), but it shouldn't come as much of a surprise. Salmonella contamination of raw animal-based pet treats has been reported for years. It's not just a risk to dogs, since outbreaks of salmonellosis in people from handling treats have also been reported. Despite some good moves by the industry to improve the situation (e.g. better manufacturing practices, more products being irradiated), treats still need to be considered high-risk for being contaminated with Salmonella and other bacteria.

So, what can be done to reduce the risk?

  • Buy individually wrapped or pre-packaged treats. Treats from bulk bins are higher risk because one contaminated item can cross-contaminate many others. Also, bins are often continually topped up without cleaning or disinfection so contamination can persist.
  • Choose products that have been irradiated. There are still some baseless fears about irradiation, but there is absolutely no evidence that irradiation of food is harmful and it can effectively kill pathogenic microorganisms.
  • Avoid feeding raw animal-based treats that have not been irradiated to animals at higher risk of becoming sick or having a serious infection. This includes elderly animals, puppies, pregnant and nursing dogs, dogs that are immunocompromised (e.g. undergoing chemotherapy) or dogs that have chronic intestinal disease.  Also, they should not be fed to dogs that have contact with high risk people, such as those that live in households with infants, elderly individuals, pregnant women or immunocompromised individuals. Also, they shouldn't be fed to dogs that visit human hospitals. One study showed that dogs fed raw animal-based treats had a 12-times greater likelihood of shedding Salmonella (Lefebvre et al 2008).
  • Wash your hands after handing pet treats.

If in doubt, or if your dog or family fits into one of those high risk groups, stick with processed treats that have been cooked or make your own cooked treats.

Pet treat recall questions

I tend not to write about recalls but the recent, large and expanding pet treat recall has lead to a lot of questions that are worth discussing. At last report, treats manufactured by Kasel Associates Industries Inc from April 20-Sept 19, 2012 were potentially contaminated with Salmonella and recalled.  Not surprisingly, most of the recalled treats are things like pig ears, bully sticks and jerky strips made from raw animal products. The impact on pets isn't clear beyond a vague statement about "a small number of complaints of illness in dogs who were exposed to the treats." Anyway, here are some common questions I've been hearing:

My dog ate a recalled treat, will it get sick? Maybe, but probably not. It's not clear how many treats were really contaminated, so it's quite possible that most products weren't contaminated. Furthermore, the dose of Salmonella that a dog ingests is important.  Low-level contamination is less of a concern, particularly in otherwise healthy dogs. The strain of Salmonella itself also plays a role since some strains seem to cause more serious disease or cause disease at lower doses than others. I haven't seen much information about the strain (or strains) involved here.

If my dog gets sick, what will happen? That's highly variable. Salmonella can cause disease ranging from vague (e.g. a little depressed and decreased appetite) to classical intestinal disease (e.g. diarrhea +/- vomiting) to rare but severe systemic disease (e.g. sudden death, bloodstream infection with subsequent overwhelming body-wide infection or focal infection of different body sites like joints).

Should my dog be tested for Salmonella? Not if it's healthy. The main question is what would be done with the result. If positive, it wouldn't mean that anything needs to be done or even that disease is likely to occur. A negative isn't very helpful either since a single sample is far from 100% sensitive. The key point is that we treat disease, not culture results. If the dog looks healthy, it's not going to be treated, regardless of the culture result. You'd also need to have the isolate tested to see if it's the same as the strain in the recalled treats if you wanted to determine whether treats were the source, and that testing is not readily available.

Should my dog be treated with antibiotics? As you can guess from the paragraph above - no. There's no evidence that antibiotic treatment of an exposed dog or a healthy carrier reduces the risk of disease or shortens the shedding time. In fact, it might even make things worse by disrupting the normal protective intestinal bacterial population, which might make disease more likely or make it harder for the body to eliminate Salmonella. Treatment might also encourage development of antibiotic resistance, something we don't need any more of with Salmonella.

What can I do to reduce the risk of disease? Not much. If a dog has eaten a Salmonella-contaminated treat, there's not really anything that can be done after the fact beyond watching for signs of disease.

So... what should I do? Relax and watch. The odds of a problem are low. If a problem develops, odds are it will be mild. That's not to say that severe disease can't or won't happen, it's just that it's unlikely and there's nothing that you can do after exposure anyway. Identifying signs consistent with early disease (e.g. lethargy, decreased appetite, diarrhea) and getting prompt veterinary care should help reduce the risk of complications or serious disease.

E coli outbreak and dog risks

I've had a few (well... more than a few) calls about potential risks to animals from the large Canadian E. coli O157 beef recall. The main concern is for dogs that are fed potentially contaminated raw meat that has been recalled, but there is also potential for exposure through cross-contamination if people in the household consumed any suspect products, and through dogs getting into garbage containing meat packaging. The other issue is whether dogs and cats can become exposed, start shedding the bacterium in their feces and subsequently infect people. Contamination of a pet's food bowl leading to human exposure is also a potential concern, especially considering the fact that as few as 10 of these E. coli bacteria can cause infection in people.

Overall, these risks are quite low. The contaminated meat is primarily a human concern. The role of E. coli O157 in disease in dogs is pretty unclear, but there's no evidence it's a significant problem. Experimentally, disease can be induced in dogs fed relatively high numbers of E. coli O157, but natural disease seems to be rare (including in dogs on beef farms where exposure is probably relatively common). I think it's reasonable to suspect that this strain of E. coli can cause disease in dogs, but it doesn't happen very often. We also don't recognize hemolytic/uremic syndrome (HUS) in dogs (the severe form of E. coli O157 infection that can cause kidney disease in people).

The risk to people from recalled meat is real. The risk to people from pets is pretty remote. Studies have not identified pet contact as a risk factor for human E. coli O157 infection. Dogs have been implicated as vectors in a limited number of specific household situations, albeit with rather weak evidence and only when focused on people and animals on beef farms.

Overall, the risks to pets and from pets are pretty limited. The main concern with the recalled meat is human disease. That being said, I wouldn't recommend people feed recalled meat to animals instead of disposing of it, since there is a possible though slight risk to both humans and animals.

Diamond pet food lawsuit

It's not the first, and it's a safe bet it's not the last, but a lawsuit has been filed against Diamond Pet Foods in response to a case of salmonellosis in a New Jersey infant. The lawsuit claims (probably correctly) that the infant acquired Salmonella from contaminated dog food that was in the household. The infant was hospitalized for three days but recovered. The lawsuit, one of at least eight that have been filed, claims negligence and fraudulent representation, and is seeking over $75000 in compensation.

In reality, it's hard to consider a company liable simply for Salmonella contamination. Various practices can be used to reduce the risk and to detect contamination when it occurs, but these will never be 100% effective. Standard hygiene practices that are recommended to reduce the risk of exposing people (especially high risk people) to any pathogens that might be found in pet food must therefore always be used. It's hard to say what degree of responsibility needs to be placed on consumers versus companies, since companies need to do their best and people need to use common sense.

From my completely non-legal standpoint, the issues of negligence and liability come in when:

  • A company has inadequate facilities that do not conform to standard requirements to reduce the risk of contamination (e.g. duct tape and cardboard in food processing equipment, as per the FDA report).
  • A company has an inadequate quality control program.
  • A company knows there's a problem and doesn't take prompt and appropriate action to correct it.

Based on what information has been released (including the relatively damning FDA report that cited lack of microbial analysis of certain ingredients, lack of hand hygiene facilities and the use of duct tape, cardboard and other non-cleanable materials in the plant) combined with some questionable communications strategies, it certainly seems like a case can be made here.

And so it continues...Diamond Pet Food Recall

The title from Food Safety News' latest report says it all: "After eight expansions, how big is the Diamond Pet Foods Recall?" It's disturbing that we can't answer that question, considering the contamination stretches back to 2011 and now it's apparent that there are problems with another one of their plants.

Accordingly to Food Safety News, the FDA has indicated Salmonella contamination has been found in Diamond's Meta, Missouri plant, in addition to the South Carolina plant that's been at the heart of the recall. However, the Missouri Salmonella contamination is from Salmonella Liverpool, a different strain from the South Carolina plant where Salmonella Infantis has been involved. So, there's no evidence that the two recalls are linked, although you have to wonder whether deficiencies that were found by the FDA at the South Carolina plant might also be present at other plants, thus creating an increased risk of Salmonella contamination.

Anecdotal information about sick animals and people associated with this recall abounds, in stark contrast to information from Diamond Pet Foods. It would be nice to have some clear communication from the company about this outbreak, and some information about what they are doing to control it and prevent it from happening again. The continued expansion of the recall and contamination is concerning, and in the absence of clear communication from the company it's hard to have confidence in the safety of any more of their products.

Diamond Pet Food outbreak continues. Diamond Pet Food Communications..not so much.

The large recall and salmonellosis outbreak associated with a variety of foods produced by Diamond Pet Foods continues to expand, in terms of species involved, the number of cases, the number of recalled products and geographic scope. The only thing that's not expanding in information from the company.

Reports (of varying strength) of Salmonella cases in dogs have been cropping up, but it's not just a US problem or a problem only involving people and dogs anymore. Two cats from a Montreal animal shelter have apparently died. At least two people in Canada have also been infected, one each from Quebec and Nova Scotia.

As with many outbreaks, the depth of information is variable when it comes to potential cases and it's hard to say if everything that's reported in the press is real. Just because an animal has been eating recalled food and gets sick, that doesn't mean that the food caused the disease. Testing is required to make the diagnosis of salmonellosis and confirm the involvement of the outbreak strain. However, enough reports are coming in to be fairly convincing that this is a very large, wide reaching outbreak involving people, dogs and cats, and multiple countries.

Communication is critical when managing an outbreak. It can let companies show they are doing everything that's necessary (and more), demonstrate their commitment to correcting the problem, show how they are helping people with affected animals, and provide confidence that once the problem was identified, it was (or will be) rectified and the product can be considered safe. Some companies shine during outbreaks. Some don't.

Here, communications don't seem to be ideal.

  • Another product was added to the recall list, without too much publicity.
  • We know recalled food is in the US, Canada and Puerto Rico (with sick people and animals in at least Canada and the US), but has contaminated food gone any further? Importantly, has information about the potential risk gone anywhere the food might have gone, since the FDA's mandate ends at the US border. eFoodAlert reports some concerning information in that regard. The Taste of the Wild website lists over 50 countries where the food is available and a correspondent for the site apparently bought a recalled product in Ireland. What is actually being done to correct problems that lead to the outbreak is also unclear.
  • I also haven't seen any press releases from the company addressing the numerous FDA violations that were identified in the outbreak investigation.

Outbreaks happen. Sometimes they're not preventable. Sometimes mistakes happen. That's an unfortunate aspect of life. However, how a company deals with those issues, both in terms of correcting the problem and restoring consumer confidence, is critical, and seems to be lacking here.

A good adage when it comes to outbreak communications is "never announce a problem without announcing a solution." That doesn't mean hide outbreak information (something that is done too often). Rather, it means don't just say that you have a problem. Be clear about your problem and at the same time be clear about what you are doing to fix it. Hopefully, Diamond Pet Foods has an aggressive ongoing response to correct these problems, and that's what consumers need to know about. In the absence of any clear information, we're left wondering whether they are doing anything at all.

Diamond Pet Food recall questions

I'm getting a lot of questions now about canine aspects of this recall, so I've addressed my take on some of the important issues below.

Can Salmonella cause disease in dogs?

Absolutely. The common myth about dogs being immune to Salmonella (mainly found on raw food sites) is just that: a myth. Dogs can and do get Salmonella infections, and it can make them sick.

Are dogs getting sick because of the recalled food?

I don't know but I suspect they are. There's no reason to think that the strain of Salmonella involved here would infect people but not dogs. The reason that there are reports of human but not canine cases could simply be because there is a formal surveillance and reporting system for humans but not dogs. Also, testing is not commonly performed on dogs with diarrhea, so large numbers of cases could go unidentified.

What would a sick dog look like?

The most common presentation of salmonellosis in dogs is diarrhea. Vomiting, lethargy and lack of appetite may also be present. Diarrhea can range from mild to severe and bloody. Chronic diarrhea can also develop but is less common. Other types of infections such as bloodstream infections can occur, with or without diarrhea, but these are pretty rare.

How do I know if my dog has salmonellosis?

The only was to know is to try to detect the Salmonella bacterium. This usually involves testing of stool samples. Culture is the standard and preferred approach, and is best done by a lab experienced with Salmonella testing and one where selective culture methods will be used. PCR, a type of molecular test, can also be used to detect Salmonella DNA. The quality of these tests (and the labs that offer them) is quite variable, but some of these tests are quite good. The downside is that all you find out with PCR testing is whether Salmonella is present or not. With culture, the bacterium can be tested further to see if it is the outbreak strain, and it can be tested for its susceptibility to antibiotics in the uncommon event that antibiotic treatment is needed.

My dog is healthy but has been fed recalled food. Should he/she be tested?

I don't recommend that. I only want to do a diagnostic test if I have a clear plan regarding how to use the results, which wouldn't be the case is a situation like this. If the dog was positive for Salmonella, I wouldn't do anything special except remind you to avoid contact with its poop (which you should be doing anyway). We don't treat Salmonella carriers - dogs that are healthy and shedding Salmonella will eliminate it on their own, usually within a couple weeks. A negative result also doesn't guarantee that the dog is truly negative. Usually we want multiple negative cultures to rule out Salmonella since it can be shed intermittently and can be hard to detect.

My dog is healthy but has been fed recalled food. Should he/she be treated with antibiotics?

NO. That's the last thing I want to do. Antibiotics are not very effective (or effective at all) at eliminating Salmonella that's living in the intestinal tract. A healthy animal shedding Salmonella is an indication that the body is handling it. It doesn't mean that disease won't occur, but one critical aspect for preventing intestinal infections is the protective effect of the gut microbiota - the trillions of bacteria that are in the gut helping suppress "bad" bugs like Salmonella. My concern with prophylactic treatment is that we might make things worse by suppressing this protective bacterial population and letting Salmonella overgrow in a situation where it otherwise would not have been an issue.

Diamond Pet Foods Salmonella outbreak

After starting off like a simple recall of potentially Salmonella-contaminated dry pet food, the Diamond Pet Food problem has now expanded into a multistate outbreak of salmonellosis in humans linked to exposure to the contaminated pet food. At last count, there were 14 affected people from 9 US states, including 5 who required hospitalization. These numbers could increase since so far they only include people who got sick up to April 1 (because it takes time for Salmonella to be grown in the lab, sent to CDC for testing and the result investigated, later cases may not have been reported yet).

This outbreak involves Salmonella Infantis, a strain that is uncommonly identified in people. Finding an increased number of infections caused by an unusual strain makes it easier to identify an outbreak, as was presumably the case here. This strain has also been isolated from various types of pet food that were produced at the Diamond Pet Foods' South Carolina plant. Despite the name, this strain of Salmonella is not more likely to infect infants, and people ranging from less than 1 year to 82 years of age have been infected.

Details about the types of contact people had with the pet food are limited. 70% of infected people reported having contact with a dog the week before getting sick. How the other 30% could have been exposed is unclear. Sometimes peoples' recall is poor, especially if they had transient contact with a pet. Individuals could have been exposed from environmental contamination when visiting a household where contaminated pet food was fed, without having direct contact with a pet. It's also possible some cases are not directly related to the outbreak and co-incidentally were exposed to the same strain from some other source.

Since we see periodic outbreaks associated with dry pet food, does that mean that other types of pet food are safer? Not really. Canned food is ultimately the safest because of the heat processing, but it's not practical for all animals.

Typically, after a report like this, I get a barrage of emails from people saying "See... we don't have large outbreaks from raw food diets so they are safer." Unfortunately, that's not the case. High pressure pasteurization (HPP) of raw food, a process that uses pressure with minimal heat to kill bacteria, is an effective method for reducing contamination of such products with harmful pathogens like Salmonella, and HPP is now being used by a couple of companies. These raw diets should be quite safe from a Salmonella standpoint. Otherwise, the risk of Salmonella contamination of raw pet foods is still very high, and if anything, the dry food outbreaks show how people can be infected from contaminated pet food.

Why don't we see large outbreaks associated with raw food? Outbreaks get detected because certain patterns or unusual findings are identified. Raw pet food associated outbreaks probably occur but are not as readily identifiable since raw meat contamination is common but involves variable Salmonella types that regularly change. In a situation like that, you can potentially have lots of people getting Salmonella from raw food, but if there is limited commonality in strains and products, it doesn't get picked up as an outbreak. That's particularly true when the  strains that are involved are the common ones found in food, since they would often be dismissed on the premise that the person likely got it from some unknown food source. Without large numbers of cases in an area or a cluster of unusual strains, the investigation wouldn't likely get very far and nothing would be reported.

How do reduce the risk of getting Salmonella from pet food (or your pet)?

  • Don't feed pets in the kitchen. This practice has been associated with an increased risk of disease in a previous outbreak of salmonellosis in children.
  • Wash your hands after handling pet food.
  • Don't let young children have contact with pet food.
  • Use common sense when handling pet feces.

More information about both Salmonella and issues pertaining to raw diets (including how to reduce the risk) can be found on the Worms & Germs Resources - Pets page.

Animal first aid kit recall

Earlier this year, there was a large recall of pre-packaged alcohol wipes made by Triad Group because of bacterial contamination and implication of the wipes in a large number of human infections. While alcohol is used as an antiseptic, bacterial spores are inherently resistant to the effects of alcohol and contamination with spore-forming bacteria can turn wipes into disease vectors. In the latest outbreak, alcohol wipes were contaminated with Bacillus cereus and implicated in the deaths of 7 people.

As an extension of the earlier recall, Creative Pet Products and MAI/Genesis (Veterinary Concepts) have recalled first aid kits marketed for use in pets and horses. In addition to the potential for contaminated alcohol wipes there is concern that the "sterile" lubricant jelly may not be so sterile, and could also be contaminated with Bacillus cereus. Additionally there is mention that the iodine pads could be contaminated with another bacterium, Elizabethkingia meningoseptica. (It sounds like they have some pretty major quality control issues. Not surprisingly, production at the plant has been suspended pending an ongoing FDA investigation.)

Anyway, anyone with one of these first aid kits should check to see if their kit is involved in the recall:

Alcohol prep pads – Kits affected:
10140 Horse Aid™ Kit
10145 Sporting Dog Kit
10148 Sporting Dog II Kit
10151 K9 First Aid Police & Military Kit
Brands: Triad or NovaPlus
All Lot Numbers

Iodine prep pads – Kits affected:
10140 Horse Aid™ Kit
10145 Sporting Dog Kit
10148 Sporting Dog II Kit
Brands: Triad or H&P Industries
Lot Numbers starting with 8, 9, 0, 1

The kits were distributed in the United States, Australia, the United Kingdom, Taiwan and Costa Rica.

If you have one of these kits, you should get rid of the affected items. For further details (and presumably how to get a refund) click here.

This Worms & Germs blog entry was originally posted on equIDblog on 09-May-11.

Another pet treat recall

Jones Natural Chews Company has recalled 2705 boxes of pig ear treats because of a "potential" for contamination with Salmonella. The recall was the result of a routine sampling program by the Washington State Department of Agriculture which revealed that the finished products contained the bacteria.

This shouldn't come as a surprise. Salmonella contamination of raw animal-based pet treats is nothing new, and contaminated treats have been implicated in outbreaks of human salmonellosis. There is a risk to pets as well, since Salmonella can cause disease ranging from mild to fatal. Typically, dogs that eat a little Salmonella don't get sick, but they may under the right circumstances, and even dogs that appear healthy can potentially infect people they are around. Handling the treats is also a risk to people, especially the very young, very old, pregnant women and people with compromised immune systems. Households with any individuals from these groups should avoid having any raw animal-based treats around (unless irradiated).  Anyone having contact with treats (whether they're in a high-risk group or not) should wash their hands afterwards.

More information about the recall can be found here.

Another pet treat recall

Merrick Pet Care has recalled Junior Texas Taffy pet treats because of the potential for contamination with Salmonella. No illnesses have been reported but contamination of treats could pose a risk to both pets and owners.

Contamination of pet treats is not uncommonly reported, but the overall scope of the problem isn't well understood. Outbreaks of salmonellosis in people have been reported in association with handling contaminated treats. The impact on animal health is unclear. Most recalls are not associated with reports of animal illness, however it's possible that small numbers of sporadic cases of disease would not be identified or reported.

Recalls like this highlight the potential risk from any pet treat or pet food. You can never absolutely eliminate risk but you can do things that will probably reduce the risk and identify situations where there are greater concerns.

  • Packaged treats may be lower risk than treats from bulk-bins, because a single contaminated item can lead to cross contamination of many others in these large bins.
  • Individually packaged irradiated treats are presumably of little to no risk.
  • "Human-grade," "premium" or other catchy descriptions have absolutely no meaning with regard to food safety.
  • People should wash their hands or use a hand sanitizer after handling treats.
  • Care should be taken when handling any animal-based pet treats, particularly in households that include people with compromised immune systems, infants, elderly individuals or pregnant women. In these households, particular attention needs to be paid to handwashing after contact with treats, or - better yet - avoiding treats (or at least non-irradiated treats) altogether.

Pet food (beef) recall: Canada

The Canadian Food Inspection Agency (CFIA) and the Public Health Agency of Canada (PHAC) have issued warnings about frozen beef pet food made by Surrey Meat Packers of Cloverdale, BC. The Beef Pet Food consisted of frozen 500 g blocks of beef (presumably raw) sold between October 8 and 23, that may contain E. coli O157.

This is a bigger concern that the periodic Salmonella recalls that have affected both raw and cooked pet foods. Salmonella is an important cause of disease, but E. coli O157 is a particularly nasty bug. This bacterium can cause very serious disease in people, including hemolytic-uremic syndrome (HUS), a life-threatening problem that can lead to kidney failure. The infectious dose is very low - all it takes is ingestion of a small number of bacteria for disease to develop. Risks to people from this recall mainly involve the potential for cross-contamination with human food or inadvertent ingestion of E. coli O157 from pet food via contaminated hands. Transmission of E. coli O157 from dogs to humans has been reported, but is probably quite rare.

The health impact of E. coli O157 in dogs is less clear. Experimental infection of dogs with the bacterium has resulted in disease, but studies of naturally occurring diarrhea have not provided convincing evidence that it is a significant cause of illness in dogs.

No illnesses have been reported in association with this batch of contaminated meat. Given that the contaminated meat was sold until October 23 (a few weeks ago), it's likely that most of the meat has already been consumed at this point. However, people who have purchased this product and still have some sitting in the freezer should check it. Affected product may not have a label indicating a packing or best before date, in which case you should assume it's contaminated (better safe than sorry). Any meat from that period (or of unknown history) should be discarded.

This is yet another important reminder of the fact that raw meat products can easily be contaminated with various pathogenic bacteria. People who choose to feed raw meat to their pets must ensure that they take careful precautions to reduce the risk of human infection from cross-contamination or contact with pet feces. More information about raw meat feeding can be found on the Worms & Germs Resources page.

Pet food/Salmonella outbreak

An article released today in the journal Pediatrics (Behravesh et al, 2010) provides more information about a salmonellosis outbreak linked to pet food. The outbreak itself is old news - I commented about it almost two years ago. What is new is the detailed epidemiological analysis of the outbreak, and there is some interesting information in the paper that is worth reporting. Here are the highlights:

Almost 50% of people who were infected were kids two years of age or younger.

  • That's not too surprising considering kids less than five years of age are a high-risk group for getting sick after being exposed to Salmonella.

Households with sick people were almost 7 times as likely to have recently purchased the affected food.

  • This provides good evidence of the link between the contaminated food and disease.

The Salmonella strain that was found in people was also found in bags of pet food at the manufacturing plant, samples from the manufacturing plant environment, and fecal samples from dogs that had eaten the food.

  • This is pretty convincing evidence that the food was the source. Because they were able to type the Salmonella strain in people and it was an uncommon strain, and they then found the same uncommon strain in food, animals and people, it paints a pretty clear picture of what happened.

Illnesses occurred over a 3 year period.

  • This is pretty concerning. This was more than a little lapse at a plant that led to contamination of a single batch of food or a short term event. This was a major failure in quality control that was undetected for a long period of time, resulting in at least 79 human infections in 21 US states.

A cluster of infections caused by the strain involved here, S. Schwarzengrund, was identified early in the outbreak. However, a link with pet food was not considered until the following year.

  • That's unfortunate but maybe not surprising. There are a lot of other more likely sources of infection that were probably focused on initially. "What kind of pet food do you feed your dog?" was unlikely to be a routine question asked of people with infections. Identification of outbreaks caused by uncommon events is difficult and typically takes more time.

People that fed their dog in the kitchen were 4 times as likely to have an infection.

  • Feeding a pet in the kitchen presumably increased the chance of cross-contamination with human food or contamination of the food preparation environment.

The cause of contamination was never identified. The authors of the paper suspected that contamination occurred after extrusion (the process during which the kibble is formed), which makes the most sense. The extrusion process results in high enough temperatures to kill bacteria like Salmonella. Possible causes of contamination include contaminated equipment used after extrusion, cross-contamination of pre- and post-extrusion food and contamination of substances (e.g. flavour enhancers) sprayed on kibble after extrusion. The fact that Salmonella was found in the room where materials were sprayed on the kibble supports this further.

In general, dry pet food is quite low-risk in terms of Salmonella contamination, but just like with other non-raw-animal products such as lettuce, tomatoes and sprouts, contamination can occur and human infections can result. The best way to reduce the risk is to use good general hygiene practices, particularly washing hands after handling food, keeping pet food and pet food bowls out of kitchens and limiting contact of young children and other high-risk individuals with pet foods.

Salmonella recalls: When to test

The recent run of Salmonella recalls in dry foods, raw foods and supplements has resulted in a lot of questions about when animals should be tested for Salmonella. In general, testing is only indicated in animals that have disease suggestive of salmonellosis. Diarrhea is the main issue, but other problems such as fever, decreased appetite and bloodstream infections can also occur. Clearly, any animal with signs such as these needs to be tested for Salmonella. However, there is no indication to test healthy dogs and cats that have been exposed to recalled products.

Why is that? An important concept in medicine is that you should always have a plan about what to do with the results of diagnostic tests - the result should have an impact on what you do. When you think about what would happen with a negative versus a positive test for Salmonella in a healthy pet, it shows why testing is not useful.

What would I tell you about a negative result?

  • I'd say it means the animal is probably negative, but it could be a false negative because of intermittent shedding of Salmonella in stool or a false negative test result.
  • I'd also say that even if there was no Salmonella, every animal is shedding multiple potentially harmful pathogens in its stool.
  • So, I'd emphasize that if the animal became sick, Salmonella still needs to be considered and that good hygiene measures should be used around the animal (particularly its stool).

What would I say about a positive result?

  • I'd say that means the animal was shedding Salmonella at the time the sample was collected, but that doesn't tell us if the animal is still shedding or how long it will do so.
  • There's no indication to treat the animal. There is no evidence that treatment of dogs and cats that are shedding Salmonella is needed. There's also no evidence that it's effective. In fact, there are concerns that giving antibiotics could prolong shedding of Salmonella and that it could increase antibiotic resistance.
  • Salmonella is certainly a public health concern, but there's not much specific to be done.
  • So, I'd emphasize that if the animal became sick, that Salmonella still needs to be considered and that good hygiene measures should be used around the animal (particularly its stool).

Since my recommendations for a positive result and a negative result from a healthy animal would be the same, why test?

Expanded Iams recall

Following on the heels of a limited recall of feline dry renal diets because of potential contamination with Salmonella, Proctor and Gamble has now recalled all Iams Veterinary Dry Products, as well as Eukanuba Naturally Wild, Eukanuba Pure and Eukanuba Custom Care Sensitive Skin. These products are sold across the US and Canada, and all products with best-before dates between July 1, 2010 and Dec 1, 2010 (so, presumably everything that is on the market at the moment) are included. The broad scope of the recall is apparently a proactive measure based on the premise that since Salmonella was found in some products made at a particular production facility, there is the potential for contamination of everything made there. More data about what they have found and how widespread the contamination is would be nice (but is not forthcoming at the moment).

No illnesses have been reported. If your pet is being fed one of the recalled diets and develops diarrhea, vomiting or other signs of illness (e.g. weakness, fever, decreased appetite), it is important to consider the possibility of Salmonella. Similarly, if any people in the house develop these types of symptoms, they should make sure their physician knows they may have been exposed to Salmonella. Presumably, the level of contamination was low and the risks to the general public (human and canine/feline) are relatively low, with higher risks to people and animals with compromised immune systems or other diseases that limit their ability to fight off a bug like Salmonella.

Frozen mice recall: Salmonella

MiceDirect, a company that sells frozen mice, rats and chicks as reptile feed, has issued a recall because of Salmonella contamination of their product. Contaminated critters have been sold across the US (except Hawaii) through mail order and pet stores, and recalled product codes can be found in the FDA recall notice. Contamination isn't a big deal for the reptiles, since carriage rates for Salmonella are already high and they are usually healthy carriers. The concern is for people who handle the frozen rodents/chicks (or who can be exposed indirectly from contaminated surfaces in the home).  There have been previous outbreaks of human Salmonella infections associated with contaminated frozen rodents.

Unlike many other recalls where the product is recalled because of contamination but without evidence of human illness, human illnesses suspected to be linked to contaminated reptile food have been identified in 17 states. In reality, reported cases may be the tip of the iceberg, and I suspect that if cases in 17 states are confirmed, there will be (or may already be) many more. Other details regarding these cases and the recall, such as the strain of Salmonella involved, haven't been released.

In response to this problem, the FDA report and the company website indicate that products from MiceDirect will be irradiated. It's not clear if this will be a standard protocol from now on, or whether it's a short-term response to the contamination problem. Considering the repeated outbreaks associated with frozen reptile food, irradiation sounds like a good standard practice. Perhaps the best way to help make (or keep) it a standard practice industry-wide is for consumers to vote with their wallets: ask for irradiated or otherwise treated (e.g. high pressure pasteurization (although I'm not sure what that would do to a mouse)) feeds to reduce the risks of contamination.

Because of recurrent problems with contaminated frozen reptile feed, if people are not buying products that are treated to eliminate contamination, they should assume that all such feed is contaminated and handle it accordingly. That means using basic practices such as:

  • keeping frozen reptile feed away from human food
  • if defrosting it in the refrigerator, keep the reptile feed in a sealed container that is not used for human food and that is disinfected afterward
  • washing hands after handling the feed
  • disinfecting any potentially contaminated surfaces that come in contact with the feed
  • discarding uneaten food promptly, since Salmonella can multiply as uneaten food sits in the open, especially in a nice, warm reptile terrarium

A link to more information about MiceDirect is available through a post on Barfblog.

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Iams recall: Salmonella

Proctor and Gamble has announced a recall of two lots of Iams' Veterinary Formulas Feline Renal, a prescription dry cat food. The lot numbers are 01384174B4 and 01384174B2. Anyone that has this food should stop using it immediately. Since these are prescription diets that should only be available through a veterinarian, affected customers should presumably contact their veterinarian for information about a replacement or refund. If a cat that has eaten this food develops diarrhea, Salmonella should be considered as a possible cause and a stool sample should be tested.

As with most of these recalls, no illnesses have been reported, although lack of reported cases doesn't necessarily mean lack of cases. While Salmonella contamination of dry pet food diets is quite uncommon, it can happen.  It's a good reason for people to make sure they wash their hands after having contact with any pet food or the pet's food bowl, and to make sure that pet food is kept separate from food meant for human consumption.

Salmonella recalls

A couple of more Salmonella recalls have occurred recently. Feline's Pride Natural Chicken Formula, a raw chicken diet, has been recalled, as has Natural Balance Sweet Potato and Chicken, a kibble diet.

Finding Salmonella in commercial raw diets is expected and I'm surprised about the recalls that have happened. If you buy raw meat, you need to assume that it's contaminated with Salmonella and various other potential pathogens. Salmonella in kibble diets is more surprising, and is a concern because people do not tend to handle kibble as potentially contaminated.

These recalls highlight a few points to me:

  • Always assume you have Salmonella and other nasties in raw meat. Careful attention to handling of raw meat and personal hygiene (e.g. handwashing) is critical.
  • While lower risk, kibble is not innocuous, so wash your hands and prevent cross-contamination of kibble with human foods.
  • "Natural," along with "organic," "super premium" and other marketing catch-words tell you nothing about the quality and safety of a product. There's no evidence that any products marketed as organic, natural, or anything else along that line are at all superior to diets produced by reputable companies, particularly diets that have undergone proper development and testing, including AAFCO feeding trials.

Salmonella recall: Pet vitamins

All lots of "Pro-Pet Adult Daily Vitamins" have been recalled by United Pet Group, Inc. because of Salmonella contamination. At least one lot has tested positive for Salmonella, although there is no mention about whether the bacterium was detected during routine testing or in response to a problem. Regardless, Salmonella contamination of these products is a concern because of the potential for disease in dogs fed the vitamins. Further, people could become infected from contact with dogs that become infected from the vitamins, or from handling the vitamins directly. If you have these vitamins, stop using them immediately. If your pet has been receiving these vitamins and develops fever, diarrhea, anorexia or any other signs of illness, take your pet to your veterinarian and make sure he/she knows there has been a chance of Salmonella exposure.

Raw food recall expanded

Nature's Variety has expanded their recall based on more concerns about Salmonella contamination of their products. In a lot of ways, this makes no sense to me since you have to assume that raw meat is contaminated with Salmonella, E. coli, Campylobacter and various other pathogens. That's been clearly shown in studies of raw meat for humans and animals, and that's why we cook meat intended for human consumption and emphasize good food handling practices. It's also why there are concerns about feeding raw meat to pets, and the explanation for various studies showing pets fed raw meat have much higher rates of shedding potentially harmful bacteria like SalmonellaYou have to assume that a reasonable percentage of Nature's Variety's food has been contaminated with Salmonella, not that this is an uncommon and preventable event.

Because of the problem or consumer concerns, Nature's Variety has announced that they will be treating all of their diets using high pressure pasteurization. Basically, this process uses very high pressures (with only a slight increase in temperature) to reduce bacterial levels. I can't find any scientific literature about the effectiveness of this method on Salmonella contamination of raw meat (it's mainly used with milk and cheese) but it should be able to greatly reduce bacterial levels in meat. That's a good thing, as long as it works. What's important to know, however, is whether it is really highly effective in this situation and whether all potentially harmful bacterial will be eliminated every time.

I'm concerned that if people think this food is "sterile" and it's not, they might not take the necessary food handling precautions. If this method usually, but not always, kills all of the bad bacteria, or if it reduces levels greatly but not completely, then there could still be the risk of infection of people and pets. This information is critical. In the absence of clear scientific data, I think we need to assume that some level of contamination could still be present (although probably much less often and at a much lower level), and make sure that proper food handling practices are used.

It's good to see this company taking measures to reduce the risks associated with raw meat feeding. Let's hope that some objective research is made available to indicate what risks might remain.

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Raw food recall: Salmonella

Nature's Variety has recalled chicken-based raw meat products because of Salmonella contamination. After a customer complaint about "digestive problems," they tested the food and found Salmonella, prompting the recall. (For more details about the recall, click here.)  In some ways, this doesn't make a lot of sense to me. If you think Salmonella contamination should be an uncommon event and a problem, you should test routinely, not wait until animals get sick. If you think that Salmonella contamination of raw meat is expected (which it is), then why test or recall? Just assume that every raw meat sample is positive for Salmonella (and Campylobacter, and E. coli). Recalling raw meat for Salmonella isn't logical. Presumably, a large percentage of the raw meat that they have sold and which they will sell in the future is contaminated, based on various studies of commercial raw meat. Handling and feeding raw meat carries an inherent risk of human and animal infections with Salmonella, Campylobacter, E. coli and other bacteria. People that feed raw meat need to understand that risk, and consider whether it's a reasonable risk for their pets and the people in the household. I don't think feeding raw meat is a good idea, but in some situations it's a particularly bad idea (e.g. when there are infants, elderly persons or immunocompromised people in the household, when the pet is very old or very young, when the pet visits high risk people).

More information about raw meat feeding can be found on the Worms & Germs Resources page.

Listeriosis in a dog from recalled meat?

A Windsor, Ontario woman is convinced that her dog acquired listeriosis afetr eating recalled hot dogs.  Last week, Maple Leaf Foods recalled various hot dog products because of low-level contamination with the bacterium Listeria monocytogenes, the cause of listeriosis. Her dog Tigger was fed four hot dogs one evening, and the next morning starting vomiting. He recovered after a few days of treatment. No specific testing was done to investigate the possibility of listeriosis.

Dogs can get listeriosis.  Non-specific signs of infection including vomiting, diarrhea and fever are most common. Neurological disease can occur in a small percentage of cases. Listeriosis is extremely rare in dogs, however, despite the fact that dogs are certainly exposed to the bacterium periodically. Just because the dog ate recalled meat and got sick, it does not mean that the dog had listeriosis.

No human illnesses have been reported in association with this recall, and it's very unlikely that this dog actually had listeriosis. It's possible but I really doubt it. Dogs get gastrointestinal disease like this all of the time, from a variety of causes. Eating four hot dogs in one night could itself cause diarrhea in some dogs.

Some tips come to mind from this story:

  • Limit feeding of treats to dogs. Four hot dogs is pretty excessive. Low fat, nutritious treats are better.
  • Pay attention to recalls. Don't eat recalled food or feed it to your pet. At the same time, don't overreact to recalls. We are exposed to potentially infectious agents on a daily basis, but a combination of our immune system, normal bacterial populations in the intestinal tract, low levels of contamination and other factors mean that we don't usually get sick. If you are concerned about listeriosis, make sure processed meats are cooked before feeding.
  • If you are really concerned or suspicious about a disease, make sure testing is done.
  • If you think food is the source of a problem, save a sample. It might be useful to test the food.

More information about listeriosis in animals is available in the Worms & Germs archives.

Bird seed recall: Salmonella

As you undoubtedly know, a large Salmonella outbreak has occurred in the US, associated with contaminated peanuts. The scope of this outbreak continues to expand in unexpected areas, including pets. The latest development is a voluntary recall of bird seed. The recall affects 20-pound packages of Wild Birds Unlimited Wildlife Blend bird food (produced by Kentucky-based Burkmann Feeds) with the manufacturing date code 81132200 2916 08124. 

The contaminated bird seed was linked to the deaths of several birds in North Carolina, and it was confirmed that the bird seed manufacturer received peanuts from the Georgia facility that was implicated in the Salmonella outbreak.

People that have used this bird seed should clear out their bird feeders, ideally while wearing gloves. The feeders should be thoroughly cleaned and then disinfected (although this may be easier said than done). Hands should be washed after handling the bird seed, potentially contaminated feeders or any other potentially contaminated items.

The risk to people is presumably quite low, but people handling the bird seed could potentially contaminate their hands with Salmonella and then inadvertently swallow some of the bacteria. Concerns are greatest in people with compromised immune systems, the very young, the elderly and people taking antibiotics, as they are more likely to get sick following exposure to small numbers of Salmonella.

More information about Salmonella can be found on the Worms & Germs Resources page.

Dog infection linked to peanut butter Salmonella outbreak

Maybe the only thing surprising about this is that it's taken this long, but there has now been a dog infection reported in association with the massive peanut butter recall due to Salmonella contamination. This outbreak has made hundreds of people sick, and caused a few deaths so far. Pets that eat contaminated "people food" or pet treats are also at risk. So, it's not too surprising that an infection in a pet has now been reported (and reported cases are usually just the tip of the iceberg).

The case reported involves a  dog in Oregon that was diagnosed with salmonellosis after being fed Happy Tails dog biscuits. The Salmonella strain recovered from the dog, who had severe diarrhea, was from the same serogroup as the strain involved in the peanut product outbreak. The product (Happy Tails Multi-Flavor dog biscuits, UPC 41163 42403, 4 lb box, “best by” date Oct 31 09) was tested at IEH Laboratories & Consulting Group in Lake Forest Park, WA and Salmonella was identified. Other products from this and several other companies have been recalled, so pet owners should check the products against recall lists.  If in doubt, do not feed your pet(s) any treats until their safety can be verified.

Salmonella can cause disease in dogs ranging from mild diarrhea to severe bloody diarrhea and bloodstream infection that can be fatal in some cases. Dogs with salmonellosis can also transmit the infection to people, because they can shed large numbers of Salmonella in their stool.

If pets have been fed potentially contaminated peanut butter or treats, they should be watched carefully for signs of diarrhea, lack of appetite or decreased activity, and taken to a veterinarian promptly if there are any concerns. There is no indication to test or treat healthy pets that have potentially been exposed. Even if stool samples were tested and Salmonella was found, treatment of healthy animals would not be recommended. As always, careful handling of stool and frequent handwashing are key factors for preventing transmission of disease to people.

Peanut butter recall now affects pet products

I'm sure you've heard about the large outbreak of salmonellosis in people in the US associated (again!) with contaminated peanut butter. Based on the extent of the outbreak, it probably should not come as a surprise that pet treats are now caught up in the recall. The FDA has announced that the recall now includes some pet food products that contain peanut paste produced by the Peanut Corporation of America (PCA) at its Blakely, Georgia processing plant. The concerns here are two-fold: the risk of disease in pets fed the treats, and risk to people handling the treats. If you have peanut butter-containing pet treats, you should stop feeding them to your pet(s) until you can determine whether or not they are affected by the recall.

The recommendation in the recall notice really applies at all times: "It is important for people to wash their hands--and make sure children wash their hands--before and, especially, after feeding treats to pets."

More information on Salmonella and pets can be found on the Womrs&Germs Resources page.