Should You Toss Leftover Cat Food? The Answer May Surprise You


Leftover cat food is a common occurrence for pet owners. Cats are notoriously picky eaters and may turn up their nose after just a few bites of food. This leaves pet owners wondering what to do with the uneaten wet or dry cat food. Can it be safely stored and reheated? How long can cat food sit out before it goes bad? What are the health risks of keeping spoiled cat food? This article will provide an overview of the issues around leftover cat food and offer solutions on storage, reheating, and disposing of uneaten portions.

How Long Can Cat Food Sit Out?

The general guideline is that wet cat food should not be left out for more than 1-2 hours before refrigerating leftovers or discarding the unused portion ( Wet food can spoil quickly at room temperature because of its high moisture content. Once exposed to air and bacteria, it can pose health risks to your cat if left unrefrigerated for too long.

According to experts, unopened cans of wet food can be stored at room temperature for up to 2 years. However, once opened, it should be refrigerated if uneaten after 1-2 hours. Refrigerated wet food lasts for 3-5 days. For wet food leftover in your cat’s bowl, it should be discarded after 1-2 hours at room temperature (

The fridge can preserve wet food longer, but only for a few days. So even refrigerated wet food should not be left for more than 3-5 days at maximum. Leaving it any longer risks spoilage and bacterial growth.

Health Risks

When cat food is left out and starts to spoil, dangerous bacteria like Salmonella, E. coli, Listeria, and Clostridium botulinum can grow and multiply quickly (source). These bacteria release toxins that can cause food poisoning in cats if ingested.

Symptoms of food poisoning in cats can include vomiting, diarrhea, fever, lethargy, dehydration, increased heart rate, and convulsions. In severe cases, food poisoning can even be fatal for cats (source). Therefore, it’s very important not to let cat food sit out for extended periods of time where dangerous bacterial growth is likely to occur.

Even refrigerating cat food that has been left out for more than 2-4 hours may not prevent bacterial growth and food poisoning. The safest approach is to promptly refrigerate or discard any wet or dry cat food that has been left uneaten for more than 30 minutes to an hour.

Identifying Spoiled Cat Food

There are a few key ways to identify if your cat’s food has spoiled:

Changes in Smell: Fresh cat food should have a pleasant smell. Spoiled food will have an unpleasant, rancid, or sour odor. Trust your nose – if it smells bad, it likely is bad (source).

Changes in Texture: Canned food that has gone bad may have a jelly-like consistency or appear slimy. Dry kibble that is stale will be harder and crunchier than normal (source).

Changes in Appearance: Look for mold growth, clumping, or color changes. Also watch for signs of moisture or humidity exposure. Any abnormal look could signal spoiled food (source).

Storage Tips

It is recommended to store wet cat food in an airtight container and refrigerate it once opened, according to (source). Wet cat food can be refrigerated for up to 5 days once opened to prevent spoilage and bacterial growth. Refrigeration inhibits bacteria growth by lowering the temperature. Place leftovers in an airtight container or resealable bag prior to refrigeration to retain freshness and prevent your fridge from absorbing food odors. Though dry cat kibble does not require refrigeration after opening, storing it in an airtight container will help keep it fresh by preventing moisture absorption or contamination from pests like ants.

Reheating Leftovers

When reheating leftover cat food, it’s important to follow proper guidelines to avoid spoilage and contamination. According to Reddit users, it is generally safe to microwave cat food as long as it is done carefully. One user suggests microwaving the food for short intervals like 5-10 seconds at a time, stirring in between, until it reaches the desired temperature (source: The food should be heated to room or body temperature but not hot. It is not recommended to microwave cat food for too long or at high power as this can cause the nutrients in the food to degrade.

You can also use a cat food warmer device designed specifically for warming refrigerated cat food. These food warmers gently heat wet food to an appropriate temperature by circulating warm water or electric heat. Just place the refrigerated food pouches or cans inside and allow it to warm for around 15 minutes before serving (source: This helps maintain the integrity of the ingredients better than microwaving.

It’s best to reheat only the portion needed for that meal and refrigerate or discard the unused portion. Do not reheat cat food more than once or leave it at room temperature for more than 2 hours before reheating or serving to your cat. With proper reheating methods, leftover cat food can be safely reheated and fed to your feline companion.

Composting Cat Food

Composting is one option for dealing with spoiled cat food. Small amounts of cat food scraps can be added to compost without issue. According to a Reddit discussion on composting cat food, canned cat food will break down and compost properly, and a small amount won’t create any odor problems even in a tumbler.

When adding cat food to compost, it’s best to bury it deep in the pile to minimize any potential smell or pest attraction, as advised by The key is keeping the amount of cat food scraps small in proportion to the rest of the compost. Spreading it out evenly can also prevent clumping.

Cat food can provide proteins and nutrients that assist the composting process. But spoiled or moldy cat food should be avoided, as it may contain harmful pathogens. Overall, composting small portions of leftover wet or dry cat food can be a useful way to recycle waste.

Donating Unused Cat Food

Many animal shelters will gladly accept donations of unused cat food. Local animal shelters are often in need of pet food and supplies to care for homeless pets. According to, donation centers can accept dry and canned dog and cat food of any brand and variety, even recently expired products. Another organization that accepts pet food donations is People and Pets Together, as stated on their website Prescription food and open bags are often accepted as well. Contact your local animal shelters to see if they have a pet food pantry or accept donations of unused cat food.

When to Toss

While cat food left out for a short while won’t always pose health risks, it’s generally best practice to toss uneaten wet or dry food after certain periods of time.

Wet or canned cat food should not be left out at room temperature for more than 2 hours before discarding, according to recommendations from Wellness Pet Foods (source). Bacteria can grow rapidly in moist cat food if left unrefrigerated.

For dry kibble, it’s fine to leave it out in your cat’s bowl for up to 24 hours, but any longer may allow mold, bacteria or bugs to contaminate it (source). Discard and wash the bowl daily.

Cats are finicky eaters, so they likely won’t finish a large bowl of food in one sitting. Consider giving smaller portions more frequently to limit waste.

When in doubt about the safety of leftovers, remember it’s better to be safe and throw it out. The small amount of wasted food is worth avoiding any risk of illness.


In summary, uneaten wet cat food should not be left out for more than 30 minutes before refrigerating or discarding. Dry cat food can be left out for longer, but any cat food exposed to moisture, rodents, or insects should be thrown away.

Check for signs of spoilage like mold, unpleasant odors, and color changes before feeding cat food to your pet. Store cat food properly in airtight, pest-free containers to maximize freshness. Rotate stock to use older food first.

Reheating leftover wet cat food is safe if done properly. Composting and donating unused, unopened cat food are other eco-friendly options for dealing with uneaten portions.

When in doubt, remember it is better to be safe than sorry. If cat food seems questionable, the best approach is to throw it out to avoid any risk of foodborne illness in pets.

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