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Can Cat Food Go Bad? How Quickly Does It Go Bad? 

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By Nicole Cosgrove

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Dr. Paola Cuevas

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Have you ever found an unopened bag of cat food in the back of a cupboard and asked yourself, “Does cat food go bad?” Safely feeding your cat is a top priority for most pet owners. There are several factors you should consider before giving your pet a bowl of food that might not be the freshest.

How to Tell if Cat Food Has Gone Bad

There are a few things that you can be aware of to tell if the cat food has gone bad.

  • Look for obvious signs of contamination, such as mold or insects in the food, making it inedible. These can be dangerous for your pet so if you are in doubt, get rid of the food before your cat dives into it. This is especially important in the case of wet cat food, which cannot be left out for as long as it will more easily attract mold, pests, and bacteria.
  • If you have found some unopened food and are unclear about its expiry date, check the smell as you put it in your cat’s dish. If it is a food you are familiar with and it doesn’t smell the same as it normally does, there is a good chance it is no longer safe to serve to your pet. If it has a foul odor, avoid using it. The same goes for the color of the food; if it is a different color than normal or seems greyer and less vivid, this indicates that it is no longer usable.
  • Watch what your cat does with the food. Another clear sign the food has gone bad is if the cat sniffs at it and passes it over. This can be for many reasons, the food may be bad or it may just have lost a lot of its smell and taste after it went stale. If your cat turns their nose up at the food you have offered them, you may have no choice but to get them brand new food.
kitten with cat food
Image Credit: fantom_rd, Shutterstock

What You Should Know About Expiry Dates

Expiry dates on packaged pet food typically indicate the “best by” date. This means that the manufacturer can guarantee the quality of the food and nutritional value within that time frame. Using food past the “best by” date may not be dangerous, but it can mean that the food has a lower nutritional value as the nutrients in the recipe degrade over time. While it might be okay to feed your cat in a pinch or for a day or two, it is not a great long-term strategy for ensuring your pet’s optimal health. Also, it is simply a risk that it is better not to take since your cat’s health is at stake!

For this reason, when you are bulk-buying cat food to store at home, check the dates on the packages to make sure you are likely to use it all before it expires. Fresh pet food will likely have an “expiry date”, and this is important to note because it can be dangerous to feed your pet after the date has passed.

How to Check Dry Food

Dry cat food is commonly dated “best by” six months to a year after it is manufactured. This can change depending on how many preservatives are used in the food, and organic or natural ingredient brands will often degrade much more quickly. If you are buying a new brand of food, make sure to check the ‘manufactured by date’ against the ‘“best by date”‘ so that you have a sense of how long the food typically lasts.

It is also important to see if the brand uses biodegradable packaging as this can also impact the lasting power of the food in storage and its chance of going bad. Once opened, dry cat food should last between two to three weeks if sealed properly between feedings. If your cat is not a heavy eater, it is a good idea to think about buying smaller bags of food to ensure freshness from the time you open the bag until the time your cat manages to finish the entire thing.

fat nebelung cat eating outdoor
Image Credit: Alesia Fes, Shutterstock

How to Check Wet Food

Wet food can have more lasting power in storage as it can range from four months to three years, depending upon how it is made and packaged. On the other hand, once opened, wet food has to be handled more carefully to prevent spoilage. If properly refrigerated, a can of open cat food will last between five to seven days. When putting the food out for your cat to eat, it should sit at room temperature for no more than four hours. After this time, it should be thrown away and not reused.

Custom-made or organic wet food usually does not have any preservatives and therefore is similar to homemade human food. For this reason, it is important to have your cat eat the entire portion in one sitting, and you may want to offer them smaller serving sizes to make sure they finish it all.

wet cat food in hepper nom nom replacement dish

The Importance of Storage

Considering where and how to store your pet food can help make it last longer. Hot temperatures and wet conditions or damp environments can cause the food to degrade faster—even if unopened. Cool and dry places are the best spots to store your pet’s food. Make sure it is stored off of the ground if there is a risk of flooding or dampness seeping through the floor.

If the food is opened, it can be a good idea to invest in a decent quality storage bin, but be sure to check that it is well-sealed and does not have any spots that leak air as this will allow the food to go stale very quickly. If the packaging is porous or biodegradable, take extra care to make sure it stays dry and away from pests. Your cat might also let you know right away if the food hasn’t been stored properly as they turn tail and walk away from a new bowl of food.


No pet owner wants to feed their companion food that has gone bad. Dealing with a pet that got sick from spoiled food can be stressful. Disposing of spoiled food that was not stored properly can also get expensive. We hope this article helps keep your cat food fresh—and safe—to eat.

Featured Image Credit: fantom_rd, Shutterstock

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