Use of medium chain fatty acids to mitigate salmonella typhimurium (ATCC 14028) on dry pet food kibbles

Abstract

This study evaluated the antimicrobial effects of medium chain fatty acids (MCFAs) against Salmonella Typhimurium (ATCC 14028) when used on dry dog food kibbles. The MIC of three MCFAs, caproic (C6), caprylic (C8), and capric (C10), was determined using the broth micro- and macrodilution assay technique. Using canola oil as a fat coating, the efficacy of each MCFA was then tested on dry dog food kibbles at 37°C for up to 5 h. The MIC was found to be 0.3125, 0.3125, and 0.625% for C6, C8, and C10, respectively. When the MCFAs were tested on fat-coated dry kibbles, all three MCFAs reduced (P ≤ 0.05) Salmonella levels by >4.5 log after 5 h when the Salmonella recovery from a no-treatment control was ~6.4 log. At each evaluation time point, the three treatments were effective in reducing (P ≤ 0.05) Salmonella loads. No countable colonies of Salmonella were detected at 4 h when the combination of C6+C8 was used on the kibbles (P ≤ 0.05), whereas with the C6+C10 combination, the Salmonella colonies were not detectable between 2 and 4 h after treatments (P ≤ 0.05). Different combinations of C8 and C10 caused Salmonella to drop to a nondetectable limit (1 CFU/g) between 1 and 5 h after treatment (P ≤ 0.05). This study suggests that the use of MCFAs during kibble coating may mitigate postprocessing Salmonella recontamination on dry dog food kibbles.