The Combination of Benzoic Acid and Essential Oils Inhibit Various Growth Parameters of 18 Common <i>Salmonella</i> Isolates

(Background) <i>Salmonella</i>, a widespread pathogen, causes millions of infections in humans and farm animals, leading to various health issues from gastroenteritis to invasive typhoid fever. Traditional methods of controlling <i>Salmonella</i>, such as the use of antibiotics, have led to antimicrobial resistance, posing significant challenges to food safety and public health. Developing effective non-antibiotic strategies to reduce <i>Salmonella</i> infections is crucial. (Objective) This study aimed to evaluate the antimicrobial efficiency of a combination of benzoic acid and essential oils (VW) against 18 common <i>Salmonella</i> isolates using a three-way approach: minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and growth kinetic analysis. (Main Ideas) The antimicrobial effects of VW were assessed using a 96-well micro-broth dilution assay, growth curve experiments, and single-cell imaging. The results showed that VW inhibited the growth of all tested <i>Salmonella</i> strains. The MIC of VW was found to be 1.50 g/L, and the MBC ranged from 1.50 to 3.00 g/L. Growth kinetic analysis revealed that VW extended the lag time, decreased the maximum growth rate, increased the time to achieve maximum growth, and limited the maximum biomass accumulated. Single-cell imaging demonstrated that VW prolonged the interval to the first cellular division during the exponential phase of growth. (Conclusion) The study concluded that VW, at the recommended inclusion level, effectively inhibited the growth of 18 tested <i>Salmonella</i> strains. These findings highlight the potential use of VW as a dietary intervention to reduce <i>Salmonella</i> infections in farm animals, offering a viable alternative to antibiotics and contributing to the reduction of drug-resistant <i>Salmonella</i> strains. Further research is warranted to explore the application of VW in farm animal production and its impact on reducing <i>Salmonella</i> contamination in the food supply chain.