Application of Lactobacillus-Derived Bacteriocins to Control Escherichia coli O157:H7 in Food Systems

Escherichia coli O157:H7 is an important foodborne pathogen that can cause serious gastrointestinal illness, and represents a significant public health threat because it has the potential to contaminate many different foods. There is rising interest in the use of bacteriocins produced by lactic acid bacteria as natural bio-preservatives for food, due to a growing demand for safe and natural food preservation methods. The present study was designed to assess and characterize the antimicrobial activity of bacteriocins originating from Lactobacillus acidophilus towards E. coli O157:H7 in different food systems. A controlled, randomized design laboratory-based experimental study was performed between winter 2024 and the beginning of summer 2025. Food matrices included meat (minced beef) and dairy products (pasteurized milk). Samples were inoculated with E. coli O157:H7, which were divided into four groups: negative control; positive control; treatment with crude bacteriocin and treatment with partially purified bacteriocin. The antimicrobial efficacy was determined by quantifying the count of bacteria (log CFU/g or mL) at various time intervals. Bacteriocin treatment resulted in a statistically significant reduction of E. coli O157:H7 counts in both food matrices (p < 0.001). In minced meat, the bacterial count decreased from 6.25 log CFU/g in the positive control group to 3.42 log CFU/g following treatment with crude bacteriocin, and further to 2.15 log CFU/g with purified bacteriocin treatment. Dairy products showed a more pronounced reduction, reaching counts of 5.80 log CFU/mL to 2.95 and 1.72 log CFU/mL, respectively. In both food systems, the partially purified form of bacteriocin was more antimicrobial than its crude counterpart. Finally, Lactobacillus acidophilus bacteriocins showed strong inhibition against E. coli O157:H7 in meat and dairy products and purification increased its effect. This discovery emphasizes the potential of bacteriocins as a natural and efficient bio-preservative in food systems which could support better food quality and safety.