To enumerate L. monocytogenes, 0.1 M phosphate buffer was added to each
stomacher bag (5-g beef slice in 45 ml of phosphate buffer), and the contents were mixed in a Stomacher 400 for 2 minutes.
Optimized phenolics from oregano and cranberry extracts were evaluated for antimicrobial activity against Listeria monocytogenes in laboratory media and in beef and fish. The antimicrobial activity increased when oregano and cranberry extracts were mixed at a ratio of 75% oregano and 25% cranberry (wt/wt) with 0.1 mg of phenolic per disk or ml, and the efficacy was further enhanced by lactic acid. The inhibition by phytochemical and lactic acid synergies was most effective when beef and fish slices were stored at 4°C.