Antimicrobial activity of olive leaf extract on selected foodborne pathogens and its effect on thermal resistance of Listeria monocytogenes in sous vide ground beef

Antimicrobial activity of a commercial olive leaf extract (OLE) against Bacillus cereus, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli O157:H7, Biotype I, Salmonella Enteritidis and Typhimurium was tested by disc diffusion assay. The Gram negative bacteria in this study were more sensitive to OLE than negatives. highest antimicrobial on L. monocytogenes which yielded the largest inhibitions zone. Effect thermal resistance both Tryptic Soy Broth supplemented with 0.6% yeast (TSBYE) sous vide packed ground beef. added TSBYE (0, 0.5, 1%) tubes beef samples inoculated (7-8 log cfu/ml-g) heated at 55, 60 65°C up 30, 20 7.5 minutes, respectively. Total reductions 0.5 1% slightly higher control (0% OLE) for all temperatures. Counts then cooked 55°C (30 min), 60°C (20 min) (7.5 0.31, 1.04 0.73 cfu/g lower those samples, results indicate that included formulation may be an additional hurdle heat processed