Chemical changes from microbial degradation occur primarily through enzymes, produced by microorganisms, which degrade proteins, lipids, carbohydrates, and other complex molecules into simpler compounds. Foodborne illness may result from microorganisms such as S. aureus, Samonella and Campylobacter species, C. perfringens, C. botulinum, L. monocytogenes, Y. enterocolitica, and mycotoxins.