How Do Microorganisms Spoil Food?

Microorganisms in food have been big news over the past few years, with recalls on everything from pet food to spinach. Food recalls draw attention to a real problem: microorganisms spoil food and can make people gravely ill. If you understand how the spoilage process works, you can take steps to prevent it, and the illness that results from food-borne pathogens.

What are Microorganisms?

• The term "microorganisms" covers all sorts of bugs and wee beasties -- essentially any living thing that is too small to see without help from a microscope. This includes molds, yeasts and bacteria. These microorganisms grow in colonies, or groups, and it is the colonies that you identify as fuzzy mold, slimy decay or a funky smell.

Microorganisms in Food

• The truth is that there are microorganisms everywhere, and there are some in and on your food at any given time. Like humans, microorganisms need food to grow, along with water and air. Left alone, microorganisms multiply, feeding on your food and the air and water naturally present in the environment. This is spoilage -- you can't eat what the microorganisms consume.

Harmful vs. Beneficial Organisms

• Most microorganisms won't make you sick, especially in small quantities. Even in larger quantities, some microorganisms are beneficial. Yeasts ferment juice into wine and grain into beer. Bacteria give tang to yogurt and cheese, and careful mold growths make blue cheese and tempeh. Other microorganisms are particularly nasty. Salmonella and E. coli are the best recognized and can make people terribly ill, even to the point of death.

Keeping Food Fresh

• The best way to avoid illness is to keep your food fresh and protected. Wash produce, and cover food tightly to keep out microorganisms. Keep food in the freezer or refrigerator, keep it dry and wrap it tightly, as warm air and moisture can encourage spoilage. If your food smells odd or shows signs of decay, throw it out to avoid getting sick.