EPISODE 61: How is the risk of Salmonella currently evolving in pet food?

Lindsay Beaton interviews Dr. James Peterson from Pet Food Solutions to explore Salmonella contamination risks and how the trend toward humanization and pure ingredients could reduce these risks.

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Host Lindsay Beaton and Dr. James Peterson, technical consultant of Pet Food Solutions, discuss where the biggest risks of Salmonella contamination can occur during pet food production, how that’s changed with different processes, and current trends that could help mitigate the occurrence of Salmonella in this episode of Trending: Pet Food.


The below transcript is from Episode 61 of the Trending: Pet Food podcast, where I spoke with Dr. James Petson, technical consultant for Pet Food Solutions, where they discussed Salmonella . You can find the episode at Trending: Pet Food, on SoundCloud or on your favorite podcast platform. This episode originally aired on May 22, 2024.

We want to thank Cargill for sponsoring this podcast. Cargill, a world leader in pet food ingredients and manufacturing, proudly offers TruMune postbiotic. TruMune is made to help modern pet food brands stand out by supporting multiple trending health claims — like gut health, balanced immunity and pet vitality. Best of all? TruMune benefits are packed into a single, low-inclusion ingredient, and it’s backed by several pet-specific research studies.

Lindsay Beaton – editor, Petfood Industry magazine, and host, Trending: Pet Food podcast: Hello, and welcome to Trending: Pet Food, the industry podcast where we cover all the latest hot topics and trends in pet food. I’m your host and editor of Petfood Industry magazine Lindsay Beaton, and I’m here today with Dr. James Peterson, technical consultant for Pet Food Solutions. Hi Jim, and welcome!

Dr. James Peterson, technical consultant for Pet Food Solutions: Hi Lindsay.

Beaton: In case you’re not familiar with Jim or Pet Food Solutions (PFS), here’s what you need to know.

Jim joined the PFS team in 2018 and has led the efforts to define and characterize the company’s products by designing and implementing scientific studies in collaboration with outside research institutions. Prior to coming to PFS, he held multiple leadership positions in research and development at Novus International, Pfizer, Pharmacia and Monsanto. He earned a Bachelor of Arts degree in Chemistry in 1977 from Lawrence University in Appleton, Wisconsin, and his Ph.D. in Synthetic Organic Chemistry in 1984 from Northwestern University. Over the course of 40 years in research and development, he has 19 patents and publications.

Pet Food Solutions is a refiner of animal fats, serving unique industries including pet food production. The company’s processes and ingredients are driven by technology that is designed to provide multiple benefits while leading the industry in the clean-and-green approach, with zero waste. PFS’s record of safety and quality is unmatched and the company prides itself on providing service that aligns with the exceptional quality of its ingredients.

Jim’s extensive experience and focus on research are why I’ve brought him on today to answer this question: How is the risk of Salmonella currently evolving in pet food?

I want to start off a conversation, Jim, by figuring out what the discussion around Salmonella in the pet food industry is even like right now and how that conversation has evolved over the last several years, because I know it has. What are people talking about right now when it comes to Salmonella and pet food?

Dr. Peterson: Salmonella contamination continues to be the leading cause of recalls across the pet food industry. The FDA has a zero-tolerance policy around Salmonella contamination. If any pet food is determined to have a Salmonella detection, then all the pet food must be recalled. They need to identify what the reason for that contamination is then to correct it and destroy the product.

It continues to be a very big issue because they continue to find pet food that's contaminated with Salmonella. We might answer this, and over the last couple of years, there have been seven different brands that have been identified in the pet food industry. It goes across all forms of product, from fresh, frozen and dry. Although there are standard protocols to prevent the Salmonella from contaminated product, it continues to happen.

The FDA and other regulatory agencies are aware of it and really do not tolerate this. The reason they don't tolerate it is because of the risk. Pets do not necessarily get too sick from Salmonella exposure, but humans do. If humans encounter the food, feeding the animal or touching the food -- they can get very, very sick. The industry understands this can be an issue. All companies think about it. Even though they think about it, and try to put in systems to prevent it, it's still happening. It's a very costly and significant problem when it does occur.

Beaton: At what point in the production process is the largest risk for Salmonella present?

Dr. Peterson: In our view, the biggest risk is around contamination. In dry pet food, the biggest risk is around the contamination that occurs with chicken fat. The reason is a standard extrusion kibble process is a high-temperature process. All the ingredients are added to the pet food before the extruded product gets heated during the extrusion process so that any contamination that would occur, Salmonella would be exposed to high temperature and then would be killed. But the chicken fat is always added after that process, because chicken fat isn't stable to high temperature. Any Salmonella contamination of the chicken fat would then result in contamination of the food itself.

There was an interesting paper in 2011 call “A Review of Salmonella Control Measures.” It talked about preventing Salmonella contamination and break it down into three categories. One is preventing contamination by using pure, uncontaminated feed ingredients, and that's where we are. Then the other important prevention measures are around the plant operation and controlling dust and exposure to birds and rodents. It's having good manufacturing practices. It’s reducing places in the line where contamination can occur, thinking through your process, and then thinking about the transportation of the final product, but also the ingredients -- that's preventing contamination.

Another major bucket is reducing multiplication of Salmonella. It's preventing places where Salmonella can multiply and grow. Which means looking at the process and looking for dead legs in the process and not allowing places where Salmonella can grow.

The other factor is killing Salmonella. That's what I just talked about in the extrusion process. A high-temperature process, where most of the ingredients are exposed to high temperatures that would kill any Salmonella that is present, but ingredients that are added after that extrusion process -- like fats, like palatants -- those are the key risks to Salmonella contaminating the food itself.

Beaton: Now you were talking about dry food, which obviously still makes up the bulk of pet food, but with different types like the fresh, frozen, raw, freeze dried, air dried all those different things -- are we seeing Salmonella risk go up? Or is it happening in new places as you introduce these other methods that don't necessarily have the high heat that extrusion has or just a completely different process in terms of making pet food?

Dr. Peterson: It's hard for me to gauge that because most of the food that's out there is still dry kibble. The recalls are across the board. Since we do see recalls in the fresh and frozen areas, and that's a small amount of the overall food that's being manufacture, maybe you think that there's more occurring there? I think in those cases, the ingredient quality is a key factor, as well as packaging and storage and other things.

The recalls are really a tip of the iceberg. The recalls are a failure of monitoring and mitigation. Before this step, here are Salmonella-contaminated products that are caught before they're sent out into the marketplace. Those are more than what goes out into the marketplace. There are even more ingredients that come in, are tested, show some contamination and rejected. There's a whole supply chain where Salmonella contamination is addressed and caught. Even seven recalls over the last couple of years, it's kind of the very tip of the iceberg. The other places are even more, and they can be very costly, not so much to the brand, but to manufacturing and still having to address the issue itself.

Beaton: Now we're talking about kind of a mix when it turns to Salmonella mitigation between trying to use high-quality ingredients that are safe and handled properly. Then the responsibility of testing said ingredients and testing your product and all of that good stuff when it comes to making sure that a contaminated product does not get out into the market, because obviously that's the goal, right? You just want a clean product out in the market that is safe for pets to eat. Is most Salmonella caught during the testing process of a finished product? Or is it caught when you're evaluating the ingredients? Is Salmonella caught more prior to processing or after processing? When does it usually show up? And where does the testing skew? Is it pretty heavy on the end of the production line or at the beginning?

Dr. Peterson: That's hard for me to say, and I think that every manufacturer has their own processes. The way we would do it at Pet Food Solution is we test every batch of fat before it leaves our plant for Salmonella. Then we have scientific information about where we've tested the chicken fat itself, where we've challenged it with Salmonella.

We've taken our Gold Shield Refined Chicken Fat that removes the nonfat components to standard chicken fat, and we've challenged it with Salmonella. We ask the question, “What happens?” We compare it to standard chicken fat. What happens with standard chicken fat is with water present, which is always present during the transportation process, Salmonella can really grow in standard chicken fat because the nonfat components in the fat -- proteins, minerals, other organic materials -- the Salmonella can use that to grow. We remove all that, so Salmonella can't grow in Gold Shell Refined Chicken Fat.

First we test that we have the scientific knowledge that even if there was some contamination that we can't control after leaving our plant, the Salmonella can't grow. But we also know that it would grow in standard chicken. I'm not aware of testing the incoming products and manufacturers, but presumably some do and some don't. About the finished product, I don't really have good knowledge about how often testing occurs, but I assume that some do and some don't.

Beaton: Let's talk a little bit more about the responsibility of ingredient suppliers when it comes to Salmonella. Obviously, there's product that gets tested before it goes out into the market. But ingredient suppliers are testing their product as well before it goes out to their customers, who are the pet food manufacturers. You've been talking about it in terms of creating an ingredient that might be resistant to Salmonella, but also still testing it before it goes out to your customers. What responsibility do you believe ingredient suppliers have? In this whole discussion about Salmonella-risk mitigation, is it is the biggest responsibility to accurately test your products and be able to provide that traceability in that paperwork to the pet food manufacturers? Are you being asked to come up with ingredients that are somehow Salmonella resistant? What are the conversations like on the ingredient supplier end of things?

Dr. Peterson: We look at our testing in our product as a differentiator. I don't think most chicken fat gets tested for Salmonella before shipment. We do test, but I think it's unusual.

I do think pet food manufacturers value that, and I think the industry will be going to more monitoring, especially as we see some of the normal processes, like additives don't really always solve the problem. It's up to the pet food manufacturer themselves, what they need, how they see the issue themselves, but ingredient that can be certified to be free of Salmonella is a real differentiator in the industry.

Beaton: In terms of the ways the industry currently handles Salmonella risk versus how it used to handle things, would you say that overall, things are getting better, and the Salmonella risk is more controlled? Or do things continue to evolve and become more complex so that the risk shifts to a different part of the process? Or you're looking at different ingredients than maybe you used to? Has it been stable in terms of risk mitigation over the years? And what the industry does? Or are there improvements being made in testing and ingredients overall, to help make pet food safer?

Dr. Peterson: My sense from going to conferences and reading the literature is that the mitigation and the prevention has not changed that much. Basically, the typical processes involve using acidifier to prevent Salmonella from growing. Lactic acid is the traditional one that is used most often. Although you'll see in the literature where different groups are looking at different types of acidifiers, but basically, it's the same concept.

Our approach has been why does Salmonella grow in chicken fat? Salmonella doesn't really grow. It can't really metabolize chicken fat, but all the nonfat ingredients can be used by Salmonella to grow. Taking a basic scientific approach and saying, “Okay, if we remove those other ingredients, those impurities, will Salmonella grow?” We've answered the question, “No, it won't grow.”

I think this has been driven by pet parents wanting fewer additives in the pet food diet. Instead of another acidifier or another new additive, what would be better are pure ingredients that, just by having a sense of higher purity, solve the problem. By using a Gold Shield Refined Chicken Fat with all the nonfat impurities removed, the Salmonella risk is reduced and the need for acidifiers is reduced. That aligns with the trends out there for pure products that are humanized.

It's like what we give our families -- we don't want more additives to cover up or hide the problems. We want the problem solved. There are multiple ways of solving it. The first is pure ingredients. The other is careful manufacturing, careful packaging -- a lot of treatment of the production of pet food in a way that prevents any Salmonella from growing. There’s a trend around humanized food and pure foods that really aligns with pure ingredients in pet food.

Beaton: We've talked about it a tiny bit. This is a little bit of a sidestep. But it's such an important topic going on in industry right now, and that is traceability. I am interested in hearing what your clients are asking of you in terms of testing results of the batches of ingredients they get from you, or paperwork in terms of the manufacturing process to create the ingredient. What are you being asked to provide in terms of traceability or paperwork, so that they then have it on hand in case it's needed for their final product in some way?

Dr. Peterson: That's a good point, Lindsay, that is key. As I said, if there is a recall, there's obviously investigation to understand what did happen. The agency and the company, of course, will want to understand to prevent it from happening again. We’re volunteering to show that our material is Salmonella-free, and we have documentation that we can provide.

We've never been involved in a recall, so we haven't had to come back to that. Traceability will be important where there is a recall or an incident in the plant. There will be a serious investigation to identify exactly why that happened, and documentation from the ingredient provider will be a key part of that. Not only documentation on is Salmonella present or not, but how you ran your process or what might have caused contamination. Ultimately, to be ready for that, any kind of ingredient manufacturer will have to be able to provide that type of information.

Beaton: That makes sense. Before we wrap up, I want to talk about the future because science is always progressing. Our testing stability is always refining. What do you think the future of minimizing the risk of Salmonella in pet food looks like? Is it in continuing to refine testing abilities? Is it being able to create ingredients that are more resistant to Salmonella? Is it a combination of the two, or something completely different that is on the horizon and isn't common practice yet?

Dr. Peterson: I think it goes to the basic knowledge of understanding Salmonella and other microbial contamination issues. What causes them? What part of a supply chain and process has the most risk? How to address it? Then marrying that with the trends in the industry and what the consumer wants.

I think it's not more additives. It's more knowledge. It’s more pure ingredients that are well characterized and are known to be resistant to microbial growth. It’s also natural ingredients. Natural ingredients either prevent Salmonella from growing or, in the ingredients themselves, Salmonella is not viable. I think the industry will move away from additives, both from having a better product and from trying to meet consumer trends that are demanded by pet parents.

Beaton: Well, thank you so much for coming on today, Jim, because food safety is obviously a significant ongoing topic in pet food. It's very necessary to stay on top of Salmonella. Like you said, there have been several cases over the last few years, and if I recall correctly, there's been a recall this year in terms of Salmonella , so it’s definitely something the industry is always staying on top of. Before we go, let's do a little plug. Where can people find more information about you and Pet Food Solutions?

Dr. Peterson: I think the best place is at our website, petfoodsolutions.com. We have a lot of information about our current products, as well as the studies we've done to show the products and how they are different from standard chicken fat. We've published a couple of white papers, and we're about to publish another one through WATT Global.

Beaton: Thank you so much. That's it for this episode of Trending: Pet Food. You can find us on petfoodindustry.comSoundCloud or your favorite podcast platform. You can also follow us on Instagram @trendingpetfoodpodcast. And if you want to chat or have any feedback, I'd love to hear from you. Feel free to drop me an email: [email protected].

And of course, thanks again to our sponsor, Cargill. This world leader in pet food ingredients and manufacturing proudly offers TruMune postbiotic. TruMune is made to help modern pet food brands stand out by supporting multiple trending health claims — like gut health, balanced immunity and pet vitality. Best of all? TruMune benefits are packed into a single low-inclusion ingredient, and it’s backed by several pet-specific research studies.)

Once again, I'm Lindsay Beaton, your host and editor of Petfood Industry magazine, and we'll talk to you next time. Thanks for tuning in!


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