Why Is the Killing of Microbes Not Within the Scope of the Commandments?

Microorganisms also fall within the animal realm. The animal realm encompasses an immense variety and complexity of beings, ranging from large entities like dragons, Garudas, and elephants, down to tiny creatures like ants, bacteria, and microorganisms. Microorganisms are ubiquitous, present in the air and on all objects. As long as a person breathes, they inhale microorganisms into their nasal passages and lungs, killing them. Microorganisms are everywhere in food and drink; modern diets are almost inseparable from them, relying on microbial fermentation. All fermented foods are produced using microorganisms – fluffy bread, various pastries, alcoholic beverages, and countless others – all are made with the help of microorganisms. Consuming them constitutes killing.

Because microorganisms are exceedingly minute, invisible to the naked eye, imperceptible, and unavoidable, and because they are intimately connected to daily life, coexisting with the physical body and living environment, sentient beings have no choice but to come into contact with them and unavoidably kill or destroy them. Otherwise, sentient beings cannot survive normally. Therefore, the Buddha did not establish precepts prohibiting the killing of microorganisms. If such killing were included, then no sentient being could avoid violating the precept against killing.

In the past, when monks went out and drank from small rivers or stagnant water in puddles, which contained not only bacteria but also small worms and the like, they would filter the water using a water-filtering bag before drinking. However, the filtered water still contained vast numbers of microorganisms. As long as they were invisible to the naked eye, drinking the water did not constitute a violation of the precepts. If they were visible to the naked eye, the water could not be drunk; drinking it would violate the precepts. The Buddha established precepts that overlook killing that is too subtle and unavoidable; this is also an inescapable karmic obstacle for sentient beings.

Although killing microorganisms does not constitute a violation of the precepts, it still involves karmic cause and effect, creating negative affinities between the parties involved. Furthermore, because microorganisms are too minuscule and insignificant, with extremely low functionality of the five aggregates, they are the most inferior, weak, and humble among all sentient beings, not being a vessel for the Dharma. If their survival conflicts with that of humans or practitioners, humans and practitioners must be preserved, sacrificing the microorganisms or utilizing them to serve humanity. Through the merit accumulated and the affinities formed by these microbial beings in this way, they will gradually be freed from the microbial realm, reborn into animals with stronger five aggregates, and ultimately attain human rebirth. For microorganisms, this is also a path of continuous evolution.