Should You Choose Food That’s Preservative-Free?

You’re trying to decide between two different brands of canned cat food. The clincher is that one is advertised online as preservative-free, so you go with that one. Will it be better for your pet?

No. Canned cat food doesn’t require preservatives. The canning process results in airtight storage, and that preserves the contents just fine. In other words, calling a canned cat food preservative-free is a marketing tool. Canned cat food in general is preservative-free, whether it says so or not.

It tends to be online marketers of cat foods who use the term rather than the manufacturers themselves. That is, you won’t tend to see the words “preservative-free” right on the can but in ads by companies that sell the food.

Can a dry cat food really be preservative-free?

It’s a different story for dry cat food. Dry food for your feline does need preservatives, in no small part because cat food tends to be very high in fat. Fat is the ingredient most prone to spoilage. (You’ve heard about how it’s bad to cook food in rancid oils, which are types of fats.) Once food is spoiled, it no longer tastes as good. More important, its nutrient levels may be reduced, and it may even be unsafe to eat.

Granted, sometimes you may see an ad online for a dry cat food that’s preservative-free. But that’s probably not the case. (If it were, the company would soon be out of business.) Dry cat foods called preservative-free by advertisers are in all likelihood free of artificial preservatives — those synthesized in a laboratory. Rather, they contain preservatives found in nature, such as various forms of vitamin E. (Yes, vitamin E is a preservative, and on a can of pet food it might be listed as something like DL-alphatocopheral acetate.)

Are natural preservatives really better for your cat?

For decades people have been claiming that artificial preservatives cause debilitating illnesses ranging from arthritis to kidney disease to cancer. But those claims just have never stood up to scientific scrutiny.

The lack of evidence hasn’t erased consumer fear, however, which is why cat food manufacturers today almost always use natural preservatives. Their aim is to please their customers.

That’s fine, but it’s important to understand that natural preservatives are not as powerful as synthetic ones — they don’t protect the food for as long. Manufacturers are aware of this and should account for that in their “best by” and “use by” dates. Your own job is to make sure you store your dry cat food properly to keep it from spoiling before its time.

Proper storage for best food preservation

A lot of people like to keep opened bags of cat food in a plastic container with an airtight lid that fits snugly. That’s a good idea. It keeps out insects and other pests. Just don’t empty the food from the bag into the container. Reputable manufacturers put a lot of research into the bags, testing the food’s shelf life in its original packaging. The bags can help nutrients from degrading. Keeping the original bag also allows you to identify the lot number and UPC code should there be a recall. They let you know if your food is from the recalled batch.

Do be sure to squeeze out as much air from the bag as possible after feeding, then close the bag as securely as possible. Air that gets in can hasten food spoilage, making nutrients break down faster than they would otherwise and also letting in potentially harmful bacteria. 

As for cat food in a can, any that is not put into the bowl should be refrigerated right away. If you’e not going to refrigerate leftover canned food, throw it out, advises the Food and Drug Administration. Your cat should not eat it several hours after is has been opened unless it has been kept at refrigerator temperatures (lower than 40 degrees Fahrenheit).

Finally, unopened cat food, both canned and dry, should be stored in a cool, dry place where the temperature does not exceed 80 degrees. Excess heat can cause nutrients to break down.