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.
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.
1) Do you know what a bully stick actually is?
2) Do you know what's in it?
A recent study headed up by Dr. Lisa Freeman, published in this month's Canadian Veterinary Journal (Freeman et al., CVJ 2013;54:50-54), looked into this by asking people what they thought bully sticks were made of, and testing the treats for calorie count and bacterial contamination.
The answer to question 1 is: bully sticks are raw, dried bull penis (which explains the need for a cuter name).
- Only 44% of people surveyed knew that.
Also, bull penis is considered a by-product, yet 71% of people that fed bully sticks to their dogs said they avoid by-products in food.
- This just shows a lack of understanding about what by-products are and their nutritional value. Many people classified things that are prohibited from by-products as being by-products, such as hooves, horns, road kill and euthanized pets. By-products aren't always bad and can, in fact, have good nutritional value. Also, they can be environmentally friendly and ethical since they are often made from nutritionally valuable parts of the animal that might otherwise be thrown out, thereby providing food for pets without taking anything out of the human food supply chain.
"What's in it?" was approached from 2 standpoints:
Firstly, caloric content was assessed.
- Treats often get ignored when thinking about a pet's caloric intake, but calorie-dense treats can certainly contribute to obesity. Fifty percent of people surveyed underestimated the calorie counts of bully sticks. The average caloric density was 3 calories/gram, and given the variation in size of bully sticks, total calorie counts for a single stick ranged from 45-133 calories (9-22 calories/inch). So, yes, size matters.
Secondly (my bit part in this study), we looked at contamination by a select group of bacteria.
- Salmonella wasn't found, which was encouraging since high Salmonella contamination rates have previously been found in some treats (mainly pig ears), and contact with pet treats has been implicated in some outbreaks of salmonellosis in people. We found Clostridium difficile in 1 treat (4% overall). That doesn't worry me too much since it's increasingly clear that we encounter this bacterium regularly. With common sense and handwashing, it's probably of little risk, but in some people (e.g. elderly, people on antibiotics, people with compromised immune systems) it might be more of a concern. We also found methicillin-resistant Staphylococcus aureus (MRSA) in one sample. This was a "livestock-associated" MRSA strain that can cause infections in people, but the risk is unclear. Theoretically, it's a potential source of exposure. If someone got MRSA on their hands from the treat then touched their nose (where MRSA likes to live) or a skin lesion (where it can cause an infection), then it could potentially cause a problem. Overall, the risk is probably quite low, but it's another reason to wash your hands after handling treats.
None of this means dog owners need to avoid bully sticks. It does mean that you should pay attention to what you feed your pet, think about treats when considering your pet's caloric intake (especially if your dog is overweight), keep treats away from high risk people (e.g. don't use a bully stick as a teething toy) and wash your hands after handling dog treats (of any kind).
Photo: A variety of bully sticks (also known as pizzle treats) often fed to dogs as chew treats (photo credit: Gergely Vaas 2006 (click for source))
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.
An Irish study has reported a high rate of Salmonella contamination in pig ear treats. Various earlier studies have identified Salmonella in pig ear treats, and human infections have been associated with contact with such treats. Recommendations for processing and handling of pig ear treats have been made and have hopefully reduced the likelihood of contamination, but there's no information about adherence to these recommendations.
In the most recent study, published in Food Research International (Adley et al. 2011), researchers purchased 102 pig ears from 4 pet shops in Limerick City, Ireland. Salmonella was detected in 28% of samples. A variety of different Salmonella types were found, including antibiotic resistant strains and types that are common causes of disease in people.
Interestingly, all of the contaminated treats were from 2 of the 4 stores. The two negative stores only sold treats sourced from within the European Union, and one of them only sold pre-packaged treats. The other two stores sold treats sourced from the EU and Brazil, and sold some in bulk bins. All positive treats were from the same distributor, and all were from bulk bins.
The high prevalence of Salmonella in these treats is concerning, particularly in light of standard guidelines for processing such treats and and EU regulation that if treats are not Salmonella-free, they must have less than 1 Salmonella bacterium per 25 g of product.
Contamination of bulk bin treats isn't surprising, as I mentioned in a post just the other day. Bulk bins allow for cross contamination, and a single positive treat (or a single contaminated hand going into the bin) can result in contamination of many other treats. Also, picking treats out of a bulk bin can potentially contaminate consumers' hands, and there's an additional concern that bulk bins are often kept at a level where young children (a high risk group) can access them.
Contact with Salmonella in pig ear treats is a risk, and people should wash their hands after any contact with a pet treat. Avoiding bulk bin treats is a good idea. Purchasing irradiated and individually packaged treats should also help reduce the risk. Unfortunately, stores do a lousy job of notifying people about the risk. As the paper states "We recommend public awareness advertising in pet shops to alert pet owners of the risks associated with pig ear pet treats and hygiene practices that should be followed."
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.
My daughter's kindergarten class is having a gingerbread cookie decorating event tomorrow. They're supposed to bring a guest (in Amy's case, me) and some items (e.g. candy sprinkles, gummies) to put on the cookies. I was surprised (but impressed) to see a statement asking people to avoid bringing items from bulk bins because of the potential for cross contamination. The concern is that bulk bin items could be contaminated with items such as nuts, which are banned from schools because of allergies.
Cross contamination can also involve bacteria, and can extend into the realm of pet treats. Salmonella contamination of rawhide treats is a problem, and rawhides and other raw pet treats have been the cause of multiple outbreaks of salmonellosis in people. Salmonella (and E. coli, and other bacteria) contamination is a concern with any raw animal-origin product, and while there have been improvements in some areas in manufacturing practices, some risk will always be present. That's why rawhides, pigs' ears and similar treats shouldn't be present in households with young children, elderly individuals or people with compromised immune systems, and why good attention to hand hygiene is needed when these products are handled. Buying individually-packaged rawhides (instead of bulk bin items) is also recommended. Bulk bins may offer some cost savings, but you are at the mercy of cross-contamination and potential accumulation of Salmonella and other bacteria. If one rawhide is contaminated, it can cross-contaminate all the other rawhides in the bin. If bins are just topped up as they get low, this can lead to contamination of a large number of rawhides. There's also the risk of exposure when you reach into the bin and grab one (and it's unlikely that you'd wash your hands afterwards).
Rawhide treats, as the name suggests, are raw treats that are literally made from the hide of typically cattle or pigs. The finding of Salmonella in rawhide treats is not particularly surprising, since Salmonella is commonly found in raw meat products, especially chicken. In this case it is not known exactly how the product may have become contaminated. High rates of contamination of raw pet treats have been reported, although a recent study reported improvement in products in Canada. This has likely occured because of action from the industry in response to outbreaks of disease in people that originated with treats. It's important to remember that any raw animal-based product that has not been treated (e.g. irradiated) to get rid of bacteria could contain harmful pathogens like Salmonella. They are best avoided, especially if high risk individuals (e.g. very young children, elderly persons or anyone with a weakened immune system) might come in contact with the treats or the pet to which the treats are fed. If you do decide to feed your pet raw animal-derived treats, care should be taken to reduce the risks of transmitting pathogens like Salmonella, as is recommended with raw meat diets. More information about raw meat feeding and Salmonella in pets can be found on the Worms & Germs Resources page.
Pet treats derived from raw animal products such as rawhides and pig ears (yes, pig ear treats are actually dried, raw pig ears) are widely available and commonly fed to pets, particularly dogs. Being a raw product, there is an inherent risk of contamination with potentially harmful bacteria such as Salmonella. In 1999, an outbreak of salmonellosis linked to contact with raw pet treats was identified in people in western Canada. A subsequent investigation found Salmonella in over 50% of pig ear treats and 38% of other animal-derived treats. Similar results were reported by a later study in the US, and other outbreaks of disease have been reported. In Canada, the pet treat industry and government groups met and made various recommendations to reduce the risk of contamination.
To evaluate the effect of these changes, a Canadian follow-up study was performed. Only 4% of treats were contaminated with Salmonella, which was a marked contrast to the earlier study. Even so, the fact that Salmonella was present in a detectable percentage of treats means that certain precautions are warranted.
- Always wash your hands thoroughly after handling pet treats such as rawhides and pig ears
- Avoid buying treats from 'bulk bins', as there may be an increased risk of cross-contamination between treats in the bin
- Buy packaged treats so that you don't have to touch them directly when buying them or bringing them home
- Never store treats in areas where other food is kept or prepared
- Ask whether the treats you are buying have been produced under the Guidelines for the Manufacturing of Natural Pet Treats for Pets. There guidelines were developed by the American Pet Products Manufacturers Association with input from the Food and Drug Administration (FDA)
- Avoid buying raw treats if you have young children or anyone with a weakened immune system living in the household, as these treats may pose a small but unnecessary risk of exposure to Salmonella
- Contaminated treats seem to be a bigger problem for people than pets, however Salmonella can also cause disease in pets. If your pet develops diarrhea after eating an animal-product treat, be sure you tell your veterinarian
Image: Pig ear dog treat from www.foodpoisonblog.com