Good nutrition is import to cats. Most pet foods come with a “best when used by” or “expiration” date on the package. Some pet owners wonder how carefully these recommendations need to be followed. Does the food actually go bad? Does it lose its nutrients?
Today I'd like to answer these questions.
Ideally, to be safest, neither you nor your pet should eat anything that has expired. For those of you that tend to eat the cottage cheese or drink the milk that expired a few days ago, you may want to know more about expiration dates for pet foods.
I believe there IS a safety margin of time with pet foods - but there is a difference, depending on the type of food. There is more of a buffer with dry food than there is with canned, semi-moist or raw food. I would never feed an expired raw food diet to a pet. I'd be cautious with semi-moist. Smell it. If it smells “bad” at all, throw it away. For most dry foods you have a buffer of about a month or so. Again - if it has any type of bad odor, immediately throw it away. Don't take chances.
Does expired food lose its nutrients? Great question. I researched this myself and also asked several experts in the field. To summarize some VERY long answers… it depends. (That was helpful, wasn't it?) From what I understand, with time some nutrients, vitamins and proteins can begin to break down. But how quickly that happens depends on the quality of the core ingredients. Some of premium brands may break down slower (and last longer) than some of the generic or lower end foods.
So, as far as expiration dates go, you often have a little “wiggle room” - but again, if you want to be safest, don't feed expired food. Throw it away.
I hope this gives you a little insight.