How to Consider Safety When Useful Microorganisms with Functions are Used as Foods

Abstract

Bacteria used as probiotics are taken orally by humans or animals as viable bacteria and are expected to have a beneficial effect on the host. A large number of microorganisms live in the intestinal tracts of humans and animals, and the balance of these microorganisms affects the intestinal environment and the host. There is a wide variety of bacteria used as probiotics. Those used commercially as foods include lactic acid bacteria and bifidobacteria, which are bacteria that mainly live in the intestinal tracts of humans and animals and have long been safely consumed by humans as fermented foods. Such probiotics are considered safe enough for healthy humans. On the other hand, when scientific papers have been published in which bacteria classified as probiotics have been isolated from diseased cells as single bacteria, there has been debate regarding their safety. Here, I will summarize how the safety of probiotics should be considered.