Effects of alternative sweeteners on lactic acid bacteria growth and the antibacterial mechanisms of their cell-free supernatants: Transcriptomic insights into Escherichia coli O157:H7 inhibition

Transcriptome analysis revealed that SAC and L. casei exposure upregulated genes related to sulfur metabolism, cationic antimicrobial peptide resistance, and two-component systems, while downregulating genes associated with flagellar assembly, chemotaxis, and biofilm formation. These findings indicate that SAC and L. casei trigger stress responses in pathogens while suppressing motility and virulence. Phenotypic assays of motility and biofilm formation supported the transcriptome data, confirming that SAC-induced gene expression changes translated into observable phenotypes.

Importantly, SAC did not affect the growth or antimicrobial activity of L. casei but selectively inhibited E. coli O157:H7 under co-culture conditions. Overall, SAC shows promise as an antimicrobial agent for controlling foodborne pathogens in the food industry.