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Preservatives in Cat Food: What the Label Tells You

By Pettings · Published Nov 1, 2026 · Scores and prices as of Nov 9, 2026

Cat food is high in fat, and fat is the part of a food that spoils first once oxygen reaches it. Preservatives slow that spoilage down. Veterinary nutritionists at Tufts University say dry dog and cat foods must contain preservatives, whether synthetic or natural, because rancid fat makes food less tasty and can lower its nutritional quality, since certain vitamins depend on stable fat (Tufts Petfoodology).

The ingredient list shows which preservatives a food uses, once you know how US labels name them.

A white kitten peeking out of a hole in a cardboard box
Photo: Qing Luo on Pexels

Why Dry Food Needs Preservatives and Cans Usually Do Not

Canning seals food in an airtight container. According to Tufts, that is why canned pet food does not require a preservative, and a can marketed as "preservative-free" is usually no different from other cans in this respect (Tufts Petfoodology).

Kibble is a different case. When Tufts looked into dry foods sold as preservative-free, the tag often came from an online store's search filter. Manufacturers themselves tend to write "no artificial preservatives," which leaves room for natural ones (Tufts Petfoodology).

How Preservatives Appear on a US Label

FDA's animal food labeling rule says that a food with an added chemical preservative must list it by its common name and also state what it does, with wording such as "preservative" or "a mold inhibitor" (21 CFR 501.22(j)). That is where entries like "chicken fat (preserved with mixed tocopherols)" come from. Vitamin E or vitamin C may also appear further down the list, and Tufts notes that the label cannot tell you whether they are there as nutrients, as preservatives or both (Tufts Petfoodology).

Some preservatives arrive inside another ingredient. FDA's rules let a maker leave an "incidental additive" off the list when it came in with another ingredient, has no technical or functional effect in the finished food and is present only at an insignificant level (21 CFR 501.100(a)(3)). Ethoxyquin is the exception. FDA's Center for Veterinary Medicine says its labeling rules apply whether it is added directly or comes in through an ingredient (FDA CVM).

The word "natural" also has a defined meaning on most US pet food labels. AAFCO lists chemically synthesized preservatives among the ingredients that do not fit its definition of natural, and labels in the majority of states must follow that definition to use the word (AAFCO).

Natural and Synthetic: What Changes

Tufts names BHA, BHT and ethoxyquin as synthetic preservatives, and vitamin E (tocopherols), vitamin C and rosemary extract as natural ones. It reports no scientific evidence tying synthetic preservatives to health problems, yet consumer demand has moved nearly all products to natural ones (Tufts Petfoodology). Pettings sees the same shift, with a few exceptions: of the 149 dry cat foods we list, six name BHA, four name ethoxyquin and one names BHT, all of them 9Lives or Meow Mix foods. Ethoxyquin shows up only in parentheses after fish meal, as in "ocean fish meal (ethoxyquin used as a preservative)", which is how FDA's labeling rule has the function stated. All three are on our Avoid List, so each one a label lists adds one to that food's count.

The trade is shelf time. Natural preservatives are less potent, so their protection runs out sooner, and Tufts says this makes the "best by" date and storage at home more important (Tufts Petfoodology). A 1994 study found the same pattern in dog food: over 12 months at room temperature, kibble preserved with mixed tocopherols deteriorated more than kibble preserved with ethoxyquin and BHA (Gross et al., 1994, a dog food study).

The Preservatives in the Pettings Database

Besides BHT and ethoxyquin above, these are the 10 preservatives that appear on the labels of the 149 dry cat foods we list. Each name links to its ingredient page, and the count shows how many of those foods use it.

  • BHA (butylated hydroxyanisole) is a synthetic antioxidant that protects fat. FDA allows it when a food's total antioxidants stay at or below 0.02 percent of its fat content (21 CFR 582.3169). Pettings score: 0/5. Found in 6 foods.
  • Citric acid is an acid on FDA's general purpose GRAS list for animal food (21 CFR 582.1033). In cat food it often appears beside tocopherols in a fat's preservative system. Pettings score: 3/5. Found in 26 foods.
  • Lactic acid is another acid on the same FDA general purpose list (21 CFR 582.1061). Pettings score: 3/5. Found in 21 foods.
  • Mixed tocopherols are a natural source of vitamin E, which Tufts lists among the natural preservatives (Tufts Petfoodology). Pettings score: 4/5. Found in 92 foods.
  • Mixed tocopherols and citric acid is how some labels name the two together, usually in parentheses after a fat. See the two entries above. Pettings score: 4/5. Found in 20 foods.
  • Apple cider vinegar helps keep food from spoiling, but FDA's definition of a "chemical preservative" leaves out vinegars, so the label does not have to state its function (21 CFR 501.22(a)(5)). Pettings score: 3/5. Found in 2 foods.
  • Potassium sorbate is a mold inhibitor on FDA's list of chemical preservatives for animal food (21 CFR 582.3640). Pettings score: 3/5. Found in 1 food.
  • Rosemary extract is a plant extract that Tufts lists with the natural preservatives (Tufts Petfoodology). It is usually paired with tocopherols, and it is the most common preservative on our list. Pettings score: 4/5. Found in 95 foods.
  • Tannic acid is a plant polyphenol taken from oak galls or tara pods. FDA's rules for human food list it mainly as a flavoring agent (21 CFR 184.1097), so on a cat food label the function phrase beside it tells you why it was added. Pettings score: 3/5. Found in 2 foods.
  • Tocopherols is the general name for the vitamin E compounds, and they appear on FDA's GRAS list of chemical preservatives for animal food (21 CFR 582.3890). Pettings score: 4/5. Found in 1 food.

Pettings scores every ingredient from 0 to 5, and our methodology page explains how those points add up to a food's ingredient score. The scores rank ingredients inside our method. A question about one particular cat belongs with that cat's veterinarian.

Two Rules Written With Cats in Mind

FDA's listings for sulfur dioxide and the sulfite salts exclude their use in meats and in foods recognized as a source of thiamin, also called vitamin B1 (21 CFR Part 582, Subpart D). A 1991 report described cats and dogs that developed thiamin deficiency on minced meat preserved with sulfur dioxide, which had destroyed the thiamin in the food (Studdert and Labuc, 1991).

Propylene glycol once kept semimoist cat foods soft. FDA excluded that use by regulation in 1996 (FDA final rule, 1996), and propylene glycol in or on cat food now sits on FDA's list of prohibited substances (21 CFR 589.1001). The Merck Veterinary Manual notes that cats fed a diet with 6 to 12 percent propylene glycol can develop Heinz bodies in their red blood cells, which then survive for a shorter time (Merck Veterinary Manual). FDA asks pet owners to report complaints about a pet food to both FDA and the manufacturer (FDA CVM).

Storing Food So the Preservative Keeps Working

FDA gives these storage tips for pet food (FDA CVM):

  • Keep dry food in its original bag, or put the whole bag inside a storage container, so the lot number and "best by" date stay with the food.
  • Store dry food and unopened cans in a cool, dry place below 80°F.
  • Wash and dry the container between bags to clear out leftover fat and crumbs.
  • Refrigerate leftover canned or pouched food at 40°F or below, or throw it out.

If your cat has a medical condition or eats a therapeutic diet, talk to your veterinarian before switching foods because of a preservative on the label. Bring the bag or a photo of the ingredient list so the conversation starts from the actual product.

Sources

Preservatives in Cat Food: What the Label Tells You
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