Bacteria can live in hotter and colder temperatures than humans, but they do best in a warm, moist, protein-rich environment that is pH neutral or low acid.
Microorganisms are everywhere. You may not see, taste, or smell them, but they hide on your body, in the air, on kitchen counters and utensils, and in food. The main microorganisms are viruses, parasites, fungi and bacteria.
This alphabetical listing of some pathogens describes their characteristics.