Food science applies chemistry, microbiology, and engineering to the science and technology of making foods.?Chemistry--because foods undergo chemical reactions when they are heated, frozen, mixed with each other, and stored.?Microbiology--because many foods are made by microorganisms (e.g., bread, cheese, yogurt, sauerkraut, tempeh), and because microorganisms cause extensive, rapid, and often dangerous spoilage.?Physics and engineering--because foods must be constructed, moved through the factory, made safe, and distributed intact to the consumer.