Preservatives in Dog Food: Friend or Foe?

As responsible pet owners, we are constantly bombarded with information about what is best for our furry friends. One area of concern that often arises is the use of preservatives in dog food. Are these additives necessary, or should we be opting for preservative-free options?

The truth is, this is one of the most controversial topics in canine nutrition. On one hand, preservatives in some form are often necessary to guarantee the shelf life of dog food. On the other hand, there are a lot of voices raising concerns about the safety of these additives.

In this text, we'll explore the world of dog food preservatives, their types, and their impact on your pet's wellbeing.

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Does Dog Food Need Preservatives?

Modern-day eating habits (of humans) are hardly imaginable without preservatives. Walk into any supermarket and start reading the labels of any kind of packaged food - you’ll soon realise many (if not all) of those products contain some sort of additive to keep them shelf-stable and/or looking pretty.

Many of those substances have scary-sounding chemical names and/or come with number codes like “E300” which can appear even more confusing. “E300” is, in fact, quite benign, because the code refers to Vitamin C, but that’s just the tip of the iceberg (1). Some additives are, indeed, quite controversial and there is research that connects them to serious health risks (2).

But that’s a whole different story we cannot possibly begin to cover here. So what about dog food? Well, as you can imagine, the stuff you can find at the pet food store often contains additives to make it non-perishable.

But how common are preservatives in dog food and are they really necessary? That depends on the type of dog food, so let’s briefly discuss each of them.

Dry Dog Food (Kibble)

Dry dog food needs to include some sort of preservative to keep it shelf stable. The typical shelf life of this type of food simply wouldn’t be possible without them.

So, if you don’t see preservatives on the ingredient list, look harder. There might not be artificial preservatives added, but there must be at least a natural version like Vitamin E / Mixed tocopherols, for example.

Let’s take a look at the common types of dog food and how their manufacturing and packaging may or may or require the addition of preservatives.

Canned Dog Food

Canned food does not need to include any kind of preservative. This is because canning is the method of preservation in this case. By employing something called a “retort process”, the manufacturers sterilise the food inside the sealed can by using the right combination of heat and pressure. This process kills all the pathogens so there is no need for any sort of additive.

In other words, if you are looking to completely avoid preservatives, canned food is probably your best bet. Of course, we cannot be 100% sure that there are no trace amounts of preservatives in the ingredients that go in every canned dog food, but in principle, this is not necessary (4).

Freeze-Dried Dog Food

Freeze drying is a process that takes the moisture out of the food without the use of heat. This way, most of the nutrients are preserved and the food doesn't spoil because there is no moisture. And, there is no need to use preservatives.

Air-Dried Dog Food

While freeze-dried and air-dried dog foods look similar, they are not the same. Air drying is achieved using (small amounts) of heat, and the moisture is usually not completely taken out. Which is why air-dried dog foods usually contain preservatives. All of the products I’ve seen lately have been preserved using natural antioxidants like mixed tocopherols or citric acid (more on that below).

In short, kibble and air-dried food will almost invariably contain some sort of preservative. Canned foods and freeze-dried foods, on the other hand, do not require additives to extend their shelf life.

Recognising Preservatives on the Ingredient List

Let’s have a look at different kinds of preservatives you might encounter on the ingredient list of your canine companion’s food.

Natural Preservatives

Examples:

All of the substances listed above are antioxidants and are quite common in dog food. These are called natural preservatives because they occur naturally in fruits and vegetables, for example, from which they can be extracted. Antioxidants prevent food from spoiling in contact with air.

Related: What Dog Food Ingredients Should I Avoid?

These kinds of additives are considered safer due to their natural origins and consumer demand has made them very popular in dog food nowadays.

Synthetic Preservatives

Examples:

On the other hand, if you look up “what ingredients to avoid in dog food” online, you’ll probably find all of the substances listed above on the list. The reason why these additives are considered controversial is the research that shows that these preservatives could be toxic and/or carcinogenic, especially at higher doses (6,7). There is very little research that focuses on dogs specifically and the results are inconclusive at best.

Many vets will still tell you that these additives are fine. At the same time, they are becoming less and less common and are mostly used in low-quality formulas because consumers want to see healthier options.

Sulphite Preservatives

Examples:

Sulphites are another type of naturally occurring compound that are sometimes used in dog food due to their preservative and antioxidant properties. You can spot these in products like pet mince or pet food rolls.

The problem with these additives is that they can cause thiamine (Vitamin B1) deficiency, which is a serious health issue. The problem can be avoided by ensuring there is enough thiamine in the food. This is prescribed by the Australian Standard for Manufacturing and Marketing of Pet Food (AS5812-2017) (8). Still, if you want to be on the safe side it might be best to avoid foods with these additives.

Are These Additives Always Listed on The Label?

So, if you want to avoid preservatives in dog food, all you need to do is check the ingredient list carefully, right? Wrong! Unfortunately, it’s not really possible to be 100% sure what exactly is in that bag of dog food.

The Australian standard for manufacturing and marketing of pet food AS5812-2017 does require manufacturers to list all the additives added to pet feed, but adhering to this standard is currently not mandatory. Additionally, even if a manufacturer lists everything they have added to the formula, there is still the possibility that the ingredients have been treated with preservatives before arriving at the plant.

My Final Thoughts

Preservatives and other additives are definitely among the most confusing topics in dog food. The need for preservatives depends on the food type, with kibble often requiring them for shelf life, while canned and freeze-dried options often go without. Despite label scrutiny, uncertainties persist due to lax standards in some regions.

Natural preservatives like mixed tocopherols are generally safer, but synthetic ones like BHA and BHT raise concerns about potential health risks. Sulphite preservatives, though natural, can lead to thiamine deficiency. Choosing dog food involves a delicate balance between the necessity for shelf stability and potential health risks.

References

1. Coughlan, M., Snelson, M. November 20, 2015. “Explainer: what are E numbers and should you avoid them in your diet?”. The Conversation. Retrieved November 16, 2023. https://theconversation.com/explainer-what-are-e-numbers-and-should-you-avoid-them-in-your-diet-43908
2. “Food additives to avoid”.  20 January, 2020. Choice. Retrieved November 16, 2023. https://www.choice.com.au/food-and-drink/food-warnings-and-safety/food-additives/articles/food-additives-you-should-avoid
3. Freeman, L.M. September 19, 2022. “Preservative-Free” Pet Food?. Petfoodology. TUFTS University. Retrieved November 20, 2023. https://vetnutrition.tufts.edu/2022/09/preservative-free-pet-food/
4. Moss, J., Plant, T.A., Edley, D. May 15, 2007. “Wet petfood processing”. Petfood Industry. Retrieved November 20, 2023. https://www.petfoodindustry.com/production/article/15451484/wet-petfood-processing
5. Coates, J. December 7, 2012. “The Pros and Cons of Preservatives in Dog Foods”. PetMD. Retrieved November 22, 2023. https://www.petmd.com/blogs/nutritionnuggets/jcoates/2012/dec/natural-artificial-preservatives-in-dog-foods-29523
6. EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP); Rychen G et al. “Safety and efficacy of butylated hydroxyanisole (BHA) as a feed additive for all animal species”. European Food Safety Authority Journal, 2018 Mar 28;16(3):e05215. doi: 10.2903/j.efsa.2018.5215.
7. Straus, M. April 24, 2019. “Problems With Artificial Preservatives in Dog Food”. Whole Dog Journal. Retrieved November 22, 2023. https://www.whole-dog-journal.com/food/problems-with-artificial-preservatives-in-dog-food/
8. “Are preservatives in pet food products a concern?”. RSPCA Knowledge Base.  Retrieved November 22, 2023. https://kb.rspca.org.au/knowledge-base/are-preservatives-in-pet-food-products-a-concern/