Generally, bacteria cannot be prevented from growing anywhere. They reproduce too quickly to be eliminated entirely. However, bacteria can be reduced, which can help reduce illnesses contracted by bacteria, but it depends on what you're talking about. Bacteria on food can be reduced by storing it properly (e.g. airtight bags, freezer, etc). Also, cooking generally eliminates bacteria on the surface of the food, but bacteria may remain on the inside of the food (especially if it is undercooked). You can also microwave food to eliminate bacteria.