Lethality of Home-Style Dehydrator Processes against Escherichia coli O157:H7 and Salmonella Serovars in the Manufacture of Ground-and-Formed Beef Jerky and the Potential for Using a Pathogen Surrogate in Process Validation

Abstract

Ground-and-formed beef jerky can be made easily at home with ground beef and kits that include spice, cure, and jerky-forming equipment. Ground beef poses inherent risks of illness due to Escherichia coli O157:H7 and Salmonella contamination, making adequate pathogen lethality important in jerky manufacturing. We evaluated the effectiveness of drying regimes at eliminating E. coli O157:H7 and Salmonella in seasoned ground-and-formed beef jerky manufactured with three home-style dehydrators and one small commercial unit. Inoculated jerky strips were dried for up to 12 or 24 h in a home-style or the commercial unit, respectively, with target drying temperatures ranging from 51.7°C (125°F) to 71.1°C (160°F). Pathogen lethality varied with seasoning, temperature, and drying time (n = 288 samples). Lethality against E. coli O157:H7 ranged from 1.5 log CFU (Jerky Xpress, 57.2°C [135°F], 4 h) to 6.4 log CFU (Gardenmaster, 68.3°C [155°F], 12 h), and varied with seasoning. Lethality against Salmonella ranged from 1.7 log CFU (Jerky Xpress, 57.2°C [135°F], 4 h) to 6.0 log CFU (Gardenmaster, 68.3°C [155°F], 12 h), and also varied with seasoning. There was a ≥5-log CFU reduction in both pathogens in 0, 10, and 27% of samples at 4, 8, and 12 h, respectively. Heating jerky for 10 min at 135°C (275°F) 4 or 6 h postdrying increased lethality, on average, 2.99 log CFU for Salmonella and 3.02 log CFU for E. coli O157:H7. The use of a lactic acid bacterium culture (Pediococcus spp.) as a pathogen surrogate accurately predicted safety in 28% of samples containing E. coli O157:H7 and 78% of Salmonella-inoculated samples.