Unless food is preserved in some manner, it begins to spoil soon after it is harvested or slaughtered. The microorganisms that can cause food spoilage include molds, yeasts and bacteria. These microorganisms are everywhere, in the air and soil, on people and animals and on the surfaces of items. They grow well in moist conditions and can easily contaminate foods.
Molds appear as fuzz on foods.
Molds can be destroyed by temperatures between 140 F and 190 F. Yeasts also grow in high or low acid environments. Yeasts may cause foods to ferment. However, they are destroyed at temperatures between 140 F and 180 F. Bacteria grow and multiply rapidly on food. Each type of bacteria varies as to the temperatures at which it can grow. They may grow at cold, warm or hot temperatures.