Benefits can be divided into direct benefits and indirect benefits, and can be further divided into benefits for human health and benefits for production; Microorganisms harmful to food, some of which are pathogenic bacteria themselves, will cause food pollution, some of which are harmless, but their metabolites are toxic and harmful to human health; There are also some microorganisms that do not cause diseases themselves and do not produce harmful metabolites. But its growth and reproduction will have some influence on production. Some microorganisms have little effect on production and health, and some microorganisms are beneficial to production and health in some cases, but harmful to production and health in some cases.