after opening a can of cat food, then covering it tightly, does it have to be refrigerated? if so, why?

Never leave cat food in the can. Put it in a pyrex dish to save. You can refrigerate it or not. If it used up that day I usually don't - cold food can make some cats throw up.

Canned food is very well cooked and it takes a while for a serious bacteria to get going in it.

Actually moistening dry food with water or milk will make it spoil much faster than the canned.

There are enough bacteria and mold spores in the air to contaminate any food left out. If conditions are right, they will multiply and the cat food will become unsafe.

Bacteria grow most rapidly in the Danger Zone—the unsafe temperatures between 40 °F and 140 °F—so it’s key to keep foods out of this temperature range.

The Danger Zone is this temperature range in which bacteria and spoilage bacteria grow quickest. Lower temperatures prevent the bacteria from growing to dangerous levels.

When chilled, the bacteria becomes dormant only to start growing again when the temperature rises. After four hours of growth, foods may be dangerously contaminated.

Proper refrigeration will not only keep foods safer but protect the quality and nutritional value as well.

Do the words: "Refrigerate after opening" appear on the tin? Seal and refrigerate anything that is in a tin, (decant it into a sealable plastic or glass container) regardless of whether it is for human or animal consumption the contents are still perishable and can became 'tainted' or spoil, causing the cat(s) to become unwell. "Open it, close it, cool it, store it". That is the best rule of thumb to follow.

It must be refrigerated to keep bacteria from growing on it. Bacteria growth can happen quite quickly on any unrefrigerated meat product. And as a bonus it keeps the flys off.

Yes, it needs to be refrigerated. It is just as perishable as human food.

bacteria will start to grow immediately. Refrigerate.

Yes. It's like a corned beef that you want to eat again when not finished.

Yes.But look at it this way the more stuff you carry in your fridge the less power it take to cool it

yeah sadly you have to put it into the fridge soo it dosnt go off and it keeps the moisture otherwise ur cat could get sick (=

Once you've opened the can, all kinds of germs and bacteria defistate it...

Do you not have a frig ?

Please keep the can cold if you don't want it to spoil..