Food spoilage is the process in which food deteriorates to the point that it is not edible to humans or its quality of edibility becomes reduced. Various external forces are responsible for the spoilage of food. Food that is capable of spoiling is referred to as perishable food.
When bacteria break down the food, acids and other waste products are created in the process. While the bacteria itself may or may not be harmful, the waste products may be unpleasant to taste or may even be harmful to one’s health.
Yeasts can be responsible for the decomposition of food with high sugar content. The same effect is useful in the production of various types of food and beverages, such as bread, yoghurt, cider, and alcoholic beverages.
Signs of food spoilage may include an appearance different from the food in its fresh forms, such as a change in colour, a change in texture, an unpleasant odour, or an undesirable taste. The item may become softer than normal. If mould occurs, it is often visible externally on the item.
Some spoiled foods are harmless to eat, and may simply be diminished in quality. But foods exhibiting certain types of spoilage may be harmful to consume. Uncooked or under-cooked animal flesh that spoils is typically quite toxic, and consumption can result in serious illness or death. The toxic effects of consuming spoiled food are known colloquially as “food poisoning”, and more properly as “foodborne illness.
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