How Long Before Dry Pet Food Starts to Go Stale?

Any pet parent, whether you have a dog, a cat, a bird, or nearly anything else, is familiar with the shelf life of food. Or, at least, we should be, right?

The idea for this post came from a person I met at the local pet store when we were both stocking up on food for our fur babies. She was complaining about how her cats had started ignoring their dry food, even though she had more than half of a big bag left. She couldn't figure out why, until it came to her; it was stale!

I've been there too. It's very tempting to buy huge bags of dry food so they last a long time and you don't need to go back to the store as often. But all it takes is one incident like hers, when you end up having to toss out a bunch of food, to realize it can all come at a cost.

But how long does dry pet food last? It's one thing to check expiration dates, but we all know those don't tell the whole story. Food can be bad a long time before it goes bad, you know?

How Long Dry Pet Food Lasts: General Guidelines

First, let's talk generalities.

Most pet food manufacturers, most pet resources, and just about every recommendation I've seen says the same basic thing.

Dry pet food is at its best for about 4-6 weeks after you open it.

Now, if you're anything like I am (and I know a lot of you are), you've definitely had food last a lot longer than that. It's not exactly rare to be giving our fur babies food that's two or three months old.

Any more than that and I don't know that I'd risk it, but let's be honest: we don't all have the luxury to toss out food when budgets are tight. As long as our fur babies are still willing to eat it, and it's not causing them harm, there's no reason not to keep giving it to them.

All of this is very dependent on a lot of different considerations, though, so let's go through them.

What Does Going Stale Mean?

What does it mean for pet food to go stale, and is it different from going bad or spoiling?

You can think of going stale as the first stage of going bad. "Stale" just means that it's no longer fresh, after all. But what does that mean on a chemical level?

When dry pet food goes stale, it means it's changing in a bad way.

• It's exposed to moisture in the atmosphere. This can cause crisp and dry kibble to lose its texture and become softer or even chewy in an unpleasant way.

• It's exposed to oxygen in the atmosphere. Oxygen does a lot of different things, but with dry pet food, the big one is reacting to the fats in the food. Dry pet food contains fat to make it nutritionally complete, and those fats break down or go rancid when exposed to oxygen.

• It loses aromatic compounds. A lot of the chemicals in pet food that give it its scent and flavor can break down with exposure to moisture and air. With less of those compounds present, the food is less appealing.

• Some nutrients also break down. The fats going bad doesn't just remove fat (the nutrient) from the food. It also removes fat-soluble things like vitamins, making the food a little less healthy for your fur baby.

All of this combines to make the food less appealing and less healthy to consume. But since it hasn't gone fully bad yet, it's not going to be actively harmful to your furry friends.

It's when these processes continue that things get bad. That's when the rancid fats take over and start to rot or stink. It's when the moisture and oxygen make for a nutritious location for bacteria and mold to grow. It's when pests like bugs can get in and start doing their thing.

Once you reach a tipping point, your fur baby will likely reject the food. Some cats and dogs have a higher tolerance for bad food (especially those that were formerly stray or feral and may have had to eat bad food just to survive), while others might be very dainty about it.

It's also possible that the food can cause your fur baby some digestive issues prior to the point where they reject it, so if you're noticing that happening without a clear explanation, consider checking your food.

What Affects How Fast Pet Food Goes Stale?

I gave the general timeline, but some foods will go stale a lot faster (or a lot slower) than others. What's going on? As it turns out, there are a lot of contributing factors.

How you store the food matters.

I've seen a lot of different ways of storing food, from crimping the top of a torn-open bag to carefully transferring it to a hermetically sealed container. Most people either use resealable bags, transfer it to a plastic sealable container, or just clip a bag closed after folding it over a few times.

As you learned above, the prime culprits for food going stale are moisture and oxygen, but they aren't the only ones. Two others also play a role: temperature and light.

I bet if you read the pet food bag, it will say "store in a cool, dry place away from direct sunlight."

The best way to store pet food is in an airtight container, away from sources of moisture, away from light, and in a cool place like a pantry. You don't need to keep it refrigerated (unless the packaging says so), but you want to avoid letting it get over 80 degrees F.

It can also be a good idea to keep the food in its original bag if you can. Put the whole bag in your airtight container. This way, you have an extra layer of protection, and the bag is likely lined in a way to help minimize the fats going rancid.

Plus, it's helpful to keep the bag just so you have expiration information and lot numbers in the case of a pet food recall.

Tip: try not to mix batches. If you're finishing up one bag and opening another, don't pour the new one into the old or vice versa. One bad kibble spoils the bag, after all!

Where you store the food matters.

Location, location, location! I've already said a cool, dry place, so that's what you want. Tucked away in a closet, in a pantry, or even on a shelf in a garage (as long as critters can't reach it) are all good options. You generally don't want the food to be exposed to high temperatures or direct light, as the heat and light can accelerate spoilage.

Incidentally, this is why I don't care for the pet food containers you can buy that are transparent. You don't need to see through them to know what's inside them, you should have a good idea of how much food is left since you're feeding your fur baby every day, and the light exposure just makes things worse.

All of this is in line with the FDA's guidance, by the way.

Your local climate matters.

If you've ever read online reviews for pet foods, you know that some people say one thing and others say the opposite. Well, they're both right, probably! Climate matters a lot.

In particular, humidity is the driving factor here. If you live in a dry climate, food is probably going to last longer because moisture can't get into it to start causing problems. On the other hand, if you live somewhere with a lot of humidity, food can go bad in a matter of a few weeks.

The ingredients in the food matter.

This is one that shouldn't be a surprise, but is for some people. Not all pet food is created the same!

In fact, you know how a lot of people argue against chemicals in their pet food, and want organic, free-range, chemical-free pet foods? Well, guess what: a lot of those chemicals are preservatives.

Now, I'm not here to pass judgment on either side. Preservatives have saved a lot of lives over the centuries by preventing famines and food spoilage that kills. On the other hand, there are some preservatives that have long-term health effects, and others we just don't know enough about yet. I don't blame anyone for wanting organic foods and treats.

Just be aware that your preservative-free foods are going to go bad faster. That's just how preservatives work. Always make sure to read the storage instructions on your pet foods. In fact, there's a decent chance that truly preservative-free pet foods should be kept refrigerated. Not all of them do (some use natural, organic preservatives instead), but it's something you want to know.

The date the food was manufactured matters.

Here's another one you might overlook: the date you buy the food is not really important. The expiration date also kind of isn't important, though it can tell you roughly when you should be concerned about the food going off.

What you might want to check for is the food's manufacturing date. Since pet foods aren't usually made locally, they have to be made somewhere, packaged, and shipped to stores. There, they could be sitting on shelves for days or weeks (or longer) before you buy them.

Sealed bags of food don't have that exposure to moisture or oxygen, though they might experience more temperature fluctuations. When fully sealed, they can last up to a year or more, depending on the food. But the longer it has been since the food was manufactured, the less time you'll have until it goes off, just in general.

There are some forms of going stale that can't be stopped by packaging, too.

What to Do if Your Pet Food is Going Stale

If you think your dry pet food is going stale, what should you do?

Well, you basically have two options: keep using it or replace it.

If you want to keep using it, you may need to find ways to make it more appealing to your fur babies again. Meal toppers, a little water and a bit of heat to make it aromatic again, or mixing it into wet food can all be options.

Just make sure that if you keep using it, that you pay attention to your pet's habits. If they're having digestive issues or if they're turning away from the food, it's probably passing the point of stale and getting into spoiled, and you want to get rid of it.

Replacing it can be annoying, especially if you have a lot left and your budget is tight, but it's better that than a sick fur baby and a vet bill.

Common Questions About Dry Pet Food Going Stale

Do you have any questions? Feel free to let me know! I've covered a couple here, but I'm sure there are more.

Is there a difference between dog and cat food?

Yes, but we're talking nutritionally. In terms of spoiling, they're basically the same; the same macronutrients, the same susceptibility to moisture and oxygen, and so on.

The differences aren't significant enough to mean you need different storage instructions.

I'm tired of throwing away stale food, what can I do?

Buy smaller batches!

There are also a lot of ways you can get monthly deliveries with just four or five weeks' worth of food, and that can save you the trip to the store if transportation is an issue.

My fur baby is already ignoring the food and it's only been a week or two! Help!

If this is the case, it might not have anything to do with the food itself. Try cleaning their food bowl, or even replacing it, in case bacteria or odors are stuck to it. You can also change up where and how you feed them and see if that helps.

If you determine it's the food itself, try looking for recall information or any sign that the container was compromised and is spoiling ahead of schedule.