Pet food storage: keeping dry, wet and raw food fresh

Dry pet food keeps best in its original bag, top folded down, inside a lidded container in a cool, dry room. Most storage problems with kibble come from humidity and open bags rather than from age alone: damp food grows mould, and warm, humid food lets storage mites breed. Wet, raw and homemade foods spoil much faster and need a refrigerator.

Dry kibble

Keep the bag, add a lid

The FDA advises storing dry pet food in its original bag with the top tightly folded down, in a cool, dry place below 80°F (about 27°C). The bag also carries the lot code and best-by date, which is how you find out whether a recalled batch is the one in your cupboard. Tipping kibble into a tub and binning the bag loses that information.

A lid still helps. In a study that followed dry dog food in 10 homes for three months, food kept in open paper bags picked up more mites, while food in sealable plastic boxes stayed largely free of them. Standing the folded bag inside a sealable bin keeps the label and adds the seal. Wash and dry the bin before each new bag so old crumbs and fat residue do not end up mixed into fresh food.

Choosing a spot for the bin

• Indoors, in a room that stays cool. Garages, sheds and utility rooms can get hot in summer and damp in winter.
• Out of direct sun, which heats the bag.
• Off the floor anywhere that floods, gets mopped or collects condensation.
• Away from cleaning products, garden chemicals and fuel.
• Sealed against rodents and pantry insects, which chew through paper bags.

How long an opened bag lasts

For an unopened bag, go by the best-by date. Once the bag is open, the picture is less settled than the usual advice suggests. A 2025 laboratory study stored an unsealed dry pet food at 25°C and 35°C and found no microbial growth and only small changes in fat oxidation over 120 days. That is one food under controlled conditions, so it does not mean any bag lasts four months on a kitchen counter.

Humidity is the bigger variable. Australian researchers found live storage mites in several brands of unopened dry dog food. Samples kept at ordinary room conditions (about 23°C, 47% relative humidity) showed no visible mites over six weeks, but in warm, humid incubation (about 26°C, 80% humidity) mites appeared in seven of nine brands, first seen after three weeks. Storage mites are considered a possible allergen source for dogs with atopic dermatitis, so this matters most for itchy, allergic dogs. In a humid climate, or for an allergic dog, buy smaller bags that get used up in a few weeks rather than a large bag that sits open for months.

Wet food

Unopened cans and pouches are shelf-stable until the date printed on them. Keep them somewhere cool and dry, and discard any can that is bulging, leaking or badly dented along a seam.

Once opened, wet food behaves like any moist, high-protein food. The FDA's advice is to promptly refrigerate or throw out unused canned and pouched food and to keep the refrigerator at 40°F (4°C) or below. Cover the opened can with a tight lid, or move the food to a sealed container, and use it within the time given on the label. Wet food left in the bowl after a meal is best thrown away rather than put back in the fridge.

Warm refrigerated food by stirring in a little warm water or letting a portion stand briefly. Do not heat food in the metal can.

Raw food

Raw meat diets can carry bacteria such as Salmonella and Listeria monocytogenes, which can make both pets and people ill. The FDA's position is that not feeding a raw diet is the single most effective way to avoid that risk. For households that do feed raw, the handling rules are the same as for raw meat in a kitchen:

• Keep it frozen until needed, and thaw it in the refrigerator, not on the counter.
• Store it sealed and separate from human food in both the freezer and the fridge.
• Use thawed food within the period the manufacturer gives, and do not refreeze it.
• Pick up what is not eaten at the meal rather than leaving it in the bowl. The CDC advises throwing away raw food leftovers that have been out at room temperature.
• Wash bowls, scoops and utensils with hot, soapy water after each use, and clean every surface the food touched.
• Wash hands with soap and water for at least 20 seconds after handling it. Supervise children doing the same.

Two further FDA points apply to every kind of food: use a dedicated scoop rather than dipping the pet's bowl into the bag, and wash that scoop as often as the bowl.

Treats

Hard biscuits and freeze-dried treats are low in moisture and keep well while sealed, but they soften and can grow mould once they absorb damp air, so reseal the pack every time. Soft, chewy treats hold more water and spoil sooner. Homemade treats have no preservatives and belong in the refrigerator or freezer, in small batches.

Signs that food has gone off

• A rancid, sour, stale or chemical smell
• Visible mould, fuzz, or clumps of damp kibble
• Wet food that is slimy, discolored or separated
• Insects, larvae, webbing or a fine dust in the bottom of the bag
• A dog or cat refusing a food it normally eats readily

Throw out mouldy food rather than picking the bad pieces out. Some moulds produce toxins. Aflatoxins, made by Aspergillus moulds on grains and nuts in warm, moist conditions, mainly damage the liver, and the Merck Veterinary Manual describes acute, fatal cases in dogs with loss of appetite, depression, bleeding and jaundice. A dog or cat that becomes lethargic, stops eating, vomits or looks yellow around the gums or eyes after eating from a suspect bag needs a vet the same day. Keep the bag, since the lot code will be needed if the food turns out to be the cause.

Sources

1. Tips for Safe Handling of Pet Food and Treats. U.S. Food and Drug Administration.
2. Pet Food Safety. Healthy Pets, Healthy People, Centers for Disease Control and Prevention.
3. House dust and storage mite contamination of dry dog food stored in open bags and sealed boxes in 10 domestic households. Veterinary Dermatology, 2011.
4. Storage mite contamination of commercial dry dog food in south-eastern Australia. Australian Veterinary Journal, 2014.
5. Effects of Temperature on the Microbial Growth and Quality of Unsealed Dry Pet Food during Storage. Food Science of Animal Resources, 2025.
6. Aflatoxicosis in Animals. Merck Veterinary Manual.