How to tell if food has gone bad

Nobody likes to throw food away. But while we try to avoid this, sometimes food goes bad. Some foods have "best before" dates, which can help us make a decision on whether or not we should eat it. But this is not the case for every food, so here's an easy guide on how you can tell if food has gone bad.
Smell

Any bad smell is a clear indicator that the food should not be consumed. Trust your nose when you smell foods such as milk or ham.
Chicken

Chicken should be pink, not grey. Sometimes it can even smell fine, but the discoloration is a clear sign it should not be eaten.
Rice

Usually, cooked rice can last up to five to six days in the fridge. More time and it can start growing a bacteria called Bacillus cereus.

This bacteria won't die even if you reheat the rice. It can cause food poisoning, so it’s better not to risk it.
Eggs

The basic test is to put them in a recipient with water. If they float, it’s a sign the eggs are not fresh and might be spoiled.
Green vegetables

When vegetables turn any other color than the one they should be (e.g. yellowish), then that’s a sign they’re going bad.
Moldy fruit

If your fruit has mold (e.g. strawberries), then it's not good to consume.
Bread

Cutting the mold off a piece of bread doesn’t make it fine to eat. As with fruit, mold spores might have infected the whole bread–you just can’t see it.
Slimy film

If there’s a slimy film on top of a food, then it’s time to throw it in the garbage. You might find this particularly on cold cuts.
Seafood

Seafood is supposed to smell fresh, like the ocean. If it smells of fish, then it’s usually a sign that it’s not fresh.
Olive oil

If it smells rancid, like glue or motor oil, don’t consume it.
Shellfish

Cooked closed clams, for instance, are usually a sign that they were dead before they got cooked. Do not try to open and eat them.
Canned goods

If they have lots of dents, cracks or any significant damage, then the food inside might be compromised.
Mushy fruit

If your fruit is mushy then it’s gone past its shelf life. Watch out for signs of mold too!
Frozen food

If your frozen food is burned, the taste and texture will also not be the same.