Technical Abstract: The objectives of this study were to investigate the influence of heat (70oC for 5 min) and cold-storage (4oC up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella Typhimurium DT104 in ground pork and to evaluate the activity of the most effective antimicrobials (cinnamon oil and olive extract) by comparing the surviving Salmonella populations in two groups. One group of pork samples was inoculated with the Salmonella culture without and the other after heat processing. Hig concentrations of the most effective compounds were then tested in heated ground pork. Samples were stored at 4oC and taken at day 0, 3, 5, and 7 for enumeration of survivors. The heating process did not affect the activity of the antimicrobials. Significant 1.3- and 3-log reductions were observed with 1.0% cinnamon oil and 5% olive extract on day 7 of storage, .respectively. The minimum concentration for a >1 log reduction was 0.8% cinnamon oil or 4% olive extract. The results demonstrate the stability of these plant antimicrobials during heating and cold storage and their effects against multi-drug resistant S. Typhimurium in ground meat. The most active formulations have the potential to enhance microbial safety of ground pork.