Fate of Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes During Curing and Drying of Beef Bresaola

Manufacturing dry-cured meat products without a thermal lethality step is a growing trend for charcuterie companies in the United States. The United States Department of Agriculture Food Safety and Inspection Service requires that hazards for ready-to-eat meat products be addressed with a scientifically valid Hazard Analysis Critical Control Point system. Because little validation literature exists for these products, an experiment was designed to investigate the safety of beef bresaola. The objective of this study was to determine the reduction of Escherichia coli O157:H7, Salmonella spp., and Listeria monocytogenes during curing and drying of bresaola.Prior to curing, whole beef semitendinosus muscle was inoculated with a mixed culture containing 3 strains each of E. coli O157:H7, Salmonella spp., and L. monocytogenes, allowed to air dry (30 min at 23°C), sprayed with a 2.5% Beefxide antimicrobial treatment (Birko Corp., Henderson, CO), and allowed to sit overnight in a walk-in cooler (2°C–4°C). Cure (NaNO3and NaNO2) and salt were applied to the beef surface 24 h after the antimicrobial treatment, and the beef was cured for 28 d (2°C–4°C). Following curing, a proprietary spice mixture was surface coated, and each piece was stuffed into beef casings (115–130 mm). The stuffed bresaola pieces were hung and allowed to dry for 35 d to a target water activity < 0.92 (13.63°C ± 2°C; relative humidity 68% ± 7%). Pathogen populations and water activity were analyzed on days 0, 1, and 2 and then weekly until day 65 of the study. Final reductions of 5.97, 5.98, and 5.44 log10 colony-forming units (CFU)/cm2 were achieved on day 65 for E. coli, Salmonella spp., and L. monocytogenes, respectively. During the entire curing and drying process, populations of each species never increased by more than 0.5 log10 CFU/cm2. The critical parameters used to cure and dry this product are sufficient to achieve the minimum 5 log10 CFU/cm2 reduction of each pathogen as required by the United States Department of Agriculture Food Safety and Inspection Service to validate process safety.