Mesophiles

Mesophiles are microorganisms whose growth is optimal at moderate temperatures, generally between about 20 and 45 °C, with many thriving near 37 °C. This category includes most foodborne pathogens, such as Salmonella, Staphylococcus aureus, and E. coli, as well as common spoilage bacteria and the lactic acid bacteria used in fermentation. Because room temperature and body temperature fall squarely in this range, keeping foods chilled below or heated above the mesophilic zone is the basis of food safety temperature control.