Assessment of Bacillus spore antimicrobial activity against Listeria monocytogenes

The study investigated the efficacy of Bacillus subtilis spore probiotics as a novel biological control agent against Listeria monocytogenes in hummus, while comparing its performance to conventional probiotic approaches. B. subtilis spores exhibit remarkable environmental resilience and targeted antimicrobial activity. In controlled broth systems, the probiotic cocktail achieved complete suppression of L. monocytogenes (<1.48 log CFU/mL) under nutrient-limited conditions, while showing minimal effect against Gram-negative pathogens (Escherichia coli O157:H7 and Salmonella Typhimurium), highlighting its selective inhibition mechanism. The spores maintained rapid germination kinetics (<6 hours) across all tested conditions, ensuring timely activation when needed. This performance substantially exceeds results typically obtained with conventional probiotics like Lactobacillus spp., which often demonstrate poor viability and inconsistent antimicrobial effects in processed foods. The findings provide compelling evidence that B. subtilis spores represent a technologically advanced solution for clean-label food preservation, offering key advantages: (1) exceptional thermal and environmental stability, maintaining viability through processing and storage; (2) targeted suppression of high-risk pathogens while preserving beneficial microbiota. The results suggest that B. subtilis spores could significantly enhance the safety of refrigerated, ready-to-eat foods without compromising product quality or consumer acceptance.