Natural antimicrobials for control of Salmonella Enteritidis in feed and in vitro model of the chicken digestive process.

This study evaluated the antimicrobial effect of essential oils (EO) and organic acids (OA) against Salmonella Enteritidis in chicken feed and during an in vitro model that mimics the chicken digestive process. The minimal inhibitory concentration (MIC) of allyl isothiocyanate (AITC), carvacrol (CV), propionic acid (PROP) and caproic acid (CAP) were individually determined. Then, based on the MICs of each compound, combinations of EOs and/or OAs were tested to evaluate their synergic antimicrobial effect. The synergic effect of AITC and CAP was the most efficient against the bacterial strain tested. Commercial feed was inoculated with a 5-strain cocktail of S. Enteritidis and treated with different doses of AITC + CAP to evaluate their effect on the growth/survival of the pathogen. In addition, the simulated digestion model was used to access the antimicrobial effect of AITC + CAP added to the feed towards S. Enteritidis and Lactobacillus plantarum. Synergistic effect was found between AITC (0.065 mM) and CAP (17.5 mM) against S. Enteritidis in chicken feed, where S. Enteritidis was reduced to undetectable levels (<1.00 log CFU/g). AITC (1.95 mM) + CAP (45 mM) also decreased (p < 0.05) the population of S. Enteritidis in the simulated digestion, while the growth of L. plantarum was not affected. Therefore, the addition of AITC + CAP in feed might be a potential natural antimicrobial able to prevent economic losses caused for Salmonella in chicken.