Comparative analysis between organic acids and acid-producing bacteria to inhibit Salmonella serovars

Acid-producing bacteria (APB) are promising alternatives for pathogen control due to their known ability to produce bacteriocins, organic acids, and other conditions that create inhospitable environments for certain pathogenic bacteria. The antimicrobial potential of 15 different species representing APB strains against seven Salmonella serovars was investigated. Each APB was characterized by its acid production (lactic, acetic, propionic, butyric, and valeric) using High-Performance Liquid Chromatography. Lactic acid was the most abundantly produced (278 mM), followed by propionic (216.9 mM) and valeric acids (83.6 mM). Next, the antimicrobial effect of the APB against seven Salmonella serovars was assessed via agar-well diffusion assay. Inhibition zones ranged from 2.51 mm to 15.57 mm, with Propionibacterium being the most effective against Salmonella, particularly P. freudenreichii, which also was characterized for producing the largest amount of organic acids. Statistically significant differences (P < 0.05) were observed among serovars, except for Newport and Typhimurium, which did not differ significantly (P > 0.05) compared to the negative control. On the other hand, Enteritidis was the most inhibited by both APB and organic acids, while Heidelberg was the least inhibited. When the inhibitory effect of APB strains and organic acids against Salmonella was compared, APB strains were significantly more effective across most serovars tested, except for S. Heidelberg.