Abstract: Combined effect of temperature and incorporation of animal fats, vegetable oils or essential oil on microbial characteristics of beef patties were investigate. Animal fats (beef and pork fats), and vegetable oils (ground nut and maize oils) were added at 20% level and essential oils (ginger and basilica essential oils) at 0.2% level. A pure culture of E. coli was inoculated in all patties before heat treatment to a core temperature of 65 C . Samples were stored at 4 C for 30days and evaluated periodically for enterobacteriacea, E. coli, Lactic acid bacteria and mesophiles. Formulation containing vegetable oils and essential oils exibited the greatest microbial reduction during cooking and consequently the higher shelf-life periods. Enterobacteriacea and E. coli growth was decelerated for at least 12 days. However no bacterial decreases was observed during storage. For all treatment pH values increased with lactic acid bacteria growth.