A bit ago I decided to discuss the importance of refrigerating wet food that has been opened and making sure that wet food is not left out for extended periods of time. Well, I was actually shocked about how many e-mails I got shortly after asking me about if there’s an amount of time dry food can be left out for. Sometimes it slips my mind how common open feeding is since we have our cats on a feeding schedule especially due to Beau’s Pica.
So is there anything wrong with leaving dry food out for your cats? Can it only be left out for a certain amount of time before it goes bad?
Well, unlike wet food, the answer to this question is completely based on the comfort level of the pet owner. I’m going to break things down for you into smaller topics to help you decide how long you want to leave your dry food out for your pet.
Expiry Dates
Best Before Dates Aren’t Always Accurate
You may know that I worked at a pet store for 2-years. Over the years of working there, I learned a lot about pet foods, what’s inside them and how they work. One of the most important jobs I had was to make sure that products were marked down 3-months before their Best Before date.
Upon products reaching their best before date, it was also my responsibility to select what foods got donated and which ones got thrown out. So, I did some research and called a few pet food manufacturers.
What I’ve learned: Dry food commonly expires 6-months past the best before date. The best before date on most dry foods is the date that manufacturers would recommend retailers to take the product off the shelf. Oftentimes retailers will donate these foods to shelters and the food is considered safe.
Note: This is not true of all pet-foods. I strongly recommend not feeding your cat wet foods that have surpassed their best before date or soft chewy treats.
Some Products Actually Never Expire
This is an odd thing to think about, however, there are a number of pet food products that never actually expire.
An example of this is Benny Bully’s. During my first year of working at the pet store, I noticed that these liver treats actually didn’t have any expiry date on them. So, again, I picked up the phone and asked why this was. The company said something along the lines of, “because it’s freeze-dried it isn’t possible for it to grow bacteria or anything that will cause your animal to get sick.” They also stated that they had to include best before dates to comply with AAFCO rules in regards to the manufacturing of pet foods.
Bacteria Cannot Grow in Extremely Dry Conditions
Although dry food does have bacteria on it (as all things do), the fact that it’s so dry makes it practically impossible for the bacteria to grow and multiply. This is especially true when it comes to kibble as kibble has to be cooked in very hot temperatures.
Most companies will also test kibble for traces of harmful bacteria such as Salmonella.
Everything Becomes Stale
The main issue with leaving kibble out isn’t the fact that it will get your cat sick, but the fact that it will dry out and become stale.
This is why many brands of food have zip seals at the top of their bags, so you can squeeze the air out and keep the food safer from oxidization. This, however, was not always the case.
Kibble was invented in 1860 as an alternative method of feeding as wet pet food was too expensive to buy and manufacture. Not only that, since there was a war going on, countries like England wanted to make sure that more expensive resources like metals for cans were being used to help win the war, versus feed animals.
This being the case, kibble was actually invented to make sure that food could last for longer periods of time without going bad. This is achieved with certain ingredients like starch.
Note: Dry food that has oxidized is not considered unsafe, however, it is considered to have less nutritional value than non-oxidized food.

How Do You Keep Food Fresh
Don’t Put Out Too Much Food
Try to learn how much your cat eats. A great start is to look at the feeding guidelines found on the side of your food bag or on the side of the can.
Take note of whether or not your cat gains or loses weight. If your cat is staying around the same healthy weight, this is a good sign that you’re feeding the right amount of food, however, if your cat gains or loses excessive weight you’re going to want to feed more or less food.
Don’t Leave Food Out for More than 48-hours
Food that is left out oxidizes. Oxidation occurs when oils come into contact with oxygen and cause foods to become rancid. It is believed that kibble takes around 48-hours to become oxidized when left out in the open and after 14-days when left in a sealed bag.
For this reason, it is usually recommended that bowls of food should be changed every other day.
Do Some Foods Oxidize Slower than others?
Absolutely. It’s ingredients that we call “anti-oxidants” that help ensure that your food remains fresh. Oftentimes these antioxidants are under the name “mixed tocopherols”
What Are Some Ways to Store Food to make sure it Oxidizes Slower?
Buy Bags With Seals
A great way to make sure that food oxidizes slower is to use the seals at the top of the bag. These are usually velcro, zip-locks or zippers. While those are great methods of closing a bag, you have to make sure to squeeze all of the air out of the bag.
Buy An Airtight Container
You may also be interested in buying an airtight container. Make sure that you get a container that is labelled as airtight as not all Tupperware or containers will ensure the freshness of the food. We have a few of these around the house for both human food and cat food!
Freeze Your Kibble
It may be a weird thing to think about, but you may want to freeze your kibble if you’re not going to be using it right away. Similar to human food, freezing kibble prevents oxidization and rotting. I personally choose not to use this method as unfreezing changes the build of the kibble and my kitties can get fairly picky.
Make Sure The Bag you Buy Has No Tears in It
It’s fairly common for bags of food to get damaged while on route to pet stores and when they are pet stores commonly will tape these bags shut.
The only issue with this is the fact that you don’t know how long these bags have been torn. Did employees catch the tears immediately, or were they preexisting from packaging?
Personally, when it comes to kibble this isn’t a huge issue for me, however, I do understand the mentality of never buying a damaged back (even if it’s reduced price.)

Always Wash Your Bowls and Containers
This is such an important issue. A lot of people simply rinse containers or bowls that old food was in. This is not good enough.
Make sure you are properly cleaning any toys, bowls or containers that dry food is in. You may not realize the amount of grime that dry food leaves behind, but if left over for too long it may actually cause health problems to your cat. Make sure that whenever you’re done a bag of food you fully clean out containers, and make sure to wash your cat’s bowl daily.
Feeding your pet from grimy containers or containers that have rancid food may lead to long-term health problems. Some of these long-term health problems include hair loss, diarrhea, kidney failure, malnutrition, liver disease, reproductive problems or cancer.
Conclusion
Although kibble doesn’t necessarily go bad in the way that we would assume it does, it is known to have a 14-day shelf life while open (before it starts losing nutritional value).
There are many ways to help extend the shelf life of it, however at the end of the day, it was developed to last for a long amount of time. So, what are the time frames you want to remember if you want the freshest kibble?
Change your kibble out of the feeding bowl daily and throw out bags of kibble after 14-days of being opened.
While I don’t agree with these optimal time-frames, as that can get very expensive, there are alternatives you can take, such as freezing kibble, or simply changing the type of food you feed your cats.