Inhibitory effect of Nigella sativa oil against Listeria monocytogenes and Salmonella Enteritidis inoculated in minced beef meat

Abstract

The control of pathogenic bacteria and oxidative factors is important to keep microbiological and physicochemical traits of meat products. In this study, cold-pressed black cumin seed oil (BCSO) was incorporated (at levels of 1, 2, and 4%, w/w) into ground beef meat (GBM) to test the antimicrobial activity of BCSO on the growth inhibition of food-borne pathogens (Listeria monocytogenes Scott A and Salmonella Enteritidis PT4) artificially inoculated (~4.5 log CFU/g) in air-packed GBM during storage at 4 °C for 15 days. BCSO was analyzed for fatty acids, sterols, tocopherols, and thymoquinone using gas chromatography and high-performance liquid chromatography. BCSO induced higher inhibition zone (15–17 mm) against both pathogenic bacteria as compared with the control. The BCSO supplementation retarded the total bacterial count, while the food-borne pathogens were unable to grow in BCSO-supplemented GBM during cold storage for 15 days. After 15 days, S. Enteritidis PT4 was more resistant than L. monocytogenes Scott A in GBM supplemented with 4% BCSO. In general, the shelf life of BCSO-supplemented GBM was extended under refrigerated conditions with low microbial loads. BCSO-supplemented GBM also improved oxidative stability and sodium dodecyl sulfate polyacrylamide gel electrophoresis profile.