Comparative genomics and chemical inactivation analysis of three Limosilactobacillus fermentum phages.

Phage infections threaten the food fermentation industry by degrading product quality and causing fermentation failure. This study compared the genomes and tolerance to chemical disinfectants (ethanol, isopropanol, sodium hypochlorite, and peracetic acid) of Limosilactobacillus (L.) fermentum phages LFP01, LFP02, and LFP03. Intact prophage regions were identified in the genomes of all three phage host strains. Furthermore, the phages were able to infect lysogenic host strains. LFP01 and LFP03 were closely related, whereas LFP02 represented a distinct lineage, suggesting genomic diversity among three analyzed phages. The core functional regions of the three phages were conserved, whereas other regions exhibited variability. Phage LFP02 exhibited the highest ethanol and isopropanol tolerance. Phage LFP03 exhibited the lowest tolerance to sodium hypochlorite. Transmission electron microscopy (TEM) and SDS-PAGE analysis revealed phage structural damage following peracetic acid inactivation. These findings improve our understanding of L. fermentum phage resistance mechanisms and provide some practical strategies for controlling phage contamination in food fermentation.