Microorganisms survive by adapting to various environments. Food is a nutrient-rich environment for microorganisms, but humans try to inhibit the growth of microorganisms in food by stressing them by controlling temperature, pH, and water activity or adding antimicrobial substances. Such stress is known to inhibit normal cell division and filament formation in some bacteria. In our laboratory, we are studying the conditions for filament formation in foodborne bacteria and the risk of filament formation on food safety.