Strong garlic smell = normal.

Foul or rotten smell + visible deterioration = a reason to discard it.

4. Garlic That Has Been Stored or Prepared Improperly

The fourth issue isn't necessarily about the garlic itself.

It is about how the garlic has been stored or prepared.

Whole garlic generally keeps best in a cool, dry, well-ventilated location.

A common mistake is putting whole garlic bulbs in a sealed plastic bag or another container where moisture can accumulate.

That trapped moisture can encourage deterioration.

Instead, whole bulbs are generally better kept somewhere dry and well ventilated.

Once garlic is peeled or chopped, however, the situation changes.

Cut or peeled garlic is more perishable than a whole bulb and should be handled and stored appropriately.

One particularly important food-safety issue involves garlic stored in oil.

Homemade garlic-in-oil mixtures can create conditions favorable to the growth of Clostridium botulinum when they are prepared and stored improperly.

Botulism is rare, but it is a serious illness.

This is why homemade garlic oil should not simply be left sitting at room temperature for long periods.

If you're preparing garlic in oil at home, use a tested food-preservation method and follow appropriate refrigeration and storage guidance.

This is an important distinction because people sometimes assume that adding garlic to oil automatically creates a healthy “infused” food that can safely sit on the kitchen counter.

Food safety does not work that way.

Preparation and storage matter.