Bacteriophage-assisted lysis and eluted genomic DNA-based detection of pathogenic bacterial contamination in food

Foodborne diseases represent a significant global health concern, with a substantial number of illnesses and fatalities reported annually owing to the consumption of contaminated food. Current methods for identifying foodborne pathogens cannot effectively distinguish live from dead bacteria or efficiently detect multiple targets. Therefore, we developed a selective detection method for three pathogenic bacteria in food samples that leverages bacteriophage-assisted live-cell lysis and exposed genomic DNA amplification. The antimicrobial activity and host specificity of these three bacteriophages were employed to confirm the target bacteria selectivity. Bacterial DNA purification using bacteriophage-assisted lysis demonstrated the superior activity of the selected phages in extracting DNA from Escherichia coli O157:H7 and Salmonella Typhimurium. The results from reactions involving the three strains, including Bacillus cereus, highlighted that a 1 h incubation period yielded the most efficient DNA extraction and purification. The polymerase chain reaction (PCR) products obtained were comparable in terms of concentration and purity with those generated using bacterial DNA prepared using a commercial kit. In the practical food sample application experiment, bacterial strains were successfully recovered and concentrated using a polyethersulfone filter, resulting in a concentration factor >3 for all samples. Furthermore, the concentration of purified bacterial DNA from contaminated kimchi cabbage exceeded 10 ng/μL. Notably, we could detect E. coli O157:H7, S. Typhimurium, and B. cereus spiked at 103 colony-forming units/mL using multiplex PCR. This innovative bacteriophage-based approach holds substantial promise for the selective and practical detection of live foodborne pathogens, thereby significantly advancing food safety standards.