Impact of Storage and Cooking Temperature on Listeria Innocua Growth in Plant-Based and Beef Proteins

Summary with Implications Listeriosis, caused by Listeria monocytogenes and other Listeria spp., is a food-borne illness, that accounts for 260 deaths annually. The objective of this study was to identify how storage method and cooking temperature impacts Listeria innocua growth in ground beef and plant-based protein patties. Patties (162 ground beef; 162 plant-based) were used in 3 replications. For each replication, patties were either inoculated (1×108 CFU) or not inoculated and stored for 26 hr at refrigeration, freezer, or room temperature. Three patties per storage method were cooked to either 145°F or 165°F and were plated before/after cooking. Nine patties without inoculation were plated before/after cooking; and 9 patties were held at room temperature for 4 h after inoculation and plated before/after cooking. The results from this study showed cooking to an internal temperature of 165°F is more effective in eliminating L. innouca in ground beef. However, for plant-based patties, no difference in L. innocua abundance was observed based on cooking temperature or storage method.