Antagonism
Japanese: 拮抗（きっこう）
A relationship where one microorganism inhibits the growth of another. Competitive exclusion through acid or antimicrobial production is typical, deeply relevant to the safety of fermented foods.
Antagonism is a relationship where one microorganism suppresses the growth of another. The opposite of symbiosis, yet in fermentation, this antagonistic relationship underpins food safety.
When lactic acid bacteria produce lactic acid and lower pH, most pathogens can no longer proliferate. Penicillium mold producing penicillin to kill surrounding bacteria is another example of antagonism.
The microbial world is built on complex relationships mixing cooperation and competition. It is precisely because of antagonism that no single microbe runs rampant, and microbial diversity is maintained. The balance between microorganisms determines fermentation quality. One of the important elements supporting fermentation's diversity.