To kill or not to kill Bacilli: opportunities for food biotechnology

Bacillus species are a spoilage and safety challenge to the food industry due to their extremely resistant endospores. To interfere with (out)growth of spores and vegetative cells, weak organic acids are suitable preservatives. To ensure their continued use while optimally preserving product quality, knowledge of resistance development is important. In Bacilli stress responses induced by weak organic acids include intracellular membrane and pH homeostasis and detoxification of reactive oxygen species. Targeted identification of inhibitors and formulation of milder antimicrobial combinations, as desired by consumers, is thereby facilitated. In addition to being food spoilers, probiotic Bacilli are known and utilized. Knowledge of weak organic acid stress resistance may be used to develop enhanced strain robustness facilitating their permanence in the gastrointestinal tract.