Most pet parents are under the impression that dry food is the most sustainable, because it doesn’t “go bad” but unfortunately that’s not true. While it makes sense to think that, just like a McDonald’s burger, this highly processed food won’t spoil… it will. So how long does kibble last after the bag is opened? Hint: the expiration date is not an indicator.

Most cat parents don’t know that the expiration date on a bag of kibble is only good for an unopened bag. Once we open that bag the expiration date becomes null and void because a chemical reaction begins.

So how long does kibble last once the bag is open?

While the appearance of most kibble will remain the same whether or not the bag has been opened, the ingredients do not. According to author and world-renowned pet food formulator, Steve Brown, dry kibble will begin to oxidize and go rancid after only 14 days. The oils and fat in dry food become tainted by oxygen once we open the bag and this can become a problem for our kitties.

Animal studies using dogs and other animals show vitamin, protein, and fat deficiencies because of rancid fat. (Quackenbush F. J Am Oil Chem Soc,1945)”

According to Science Direct, “Studies show that frequent consumption of oxidized fats may cause cancer and contribute to many chronic health problems.

So you can see why it’s important to not feed our cats rancid cat food. While we don’t recommend feeding kibble to your cats, there are ways to help prevent oxidation if you do.

  1. Purchase smaller bags of food and be sure your cat consumes it within 7-14 days.
  2. Store your cat’s kibble in the freezer. 

Freezing dry food helps slow the oxidation process, so you can buy more time by storing the bag in the freezer. 🙂


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