Destruction of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Staphylococcus aureus achieved during manufacture of whole-muscle beef jerky in home-style dehydrators
Posted: October 31st, 2010 - 8:49pm
Source: Journal of Food Protection®, Volume 73, Number 11, pp. 2034-2042(9)
Adequate lethality in jerky manufacture destroys appropriate levels of Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, and Staphylococcus aureus. Our goal was to evaluate the lethality of four home-style dehydrator processes against these pathogens. Whole-muscle beef strips were inoculated with L. monocytogenes (five strains), S. aureus (five strains), or a mixed inoculum of E. coli O157:H7 (five strains) and Salmonella (eight strains). After allowing for attachment, strips were marinated in Colorado-, Original-, or Teriyaki-seasoned marinade for 22 to 24 h and dried in three home-style dehydrators (Garden Master, Excalibur, and Jerky Xpress) at 57.2 to 68.3°C. Samples were taken postmarination; after 4, 6, and 8 h of drying; and after drying, followed by heating for 10 min in a 135°C oven. Surviving inocula were enumerated. With a criterion of ≥5.0-log CFU/cm2 reduction as the standard for adequate process lethality, none of the samples achieved the target lethality for any pathogen after 4 h of drying, even though all samples appeared "done" (water activity of less than 0.85). A postdehydration oven-heating step increased the proportion of samples meeting the target lethality after 4 h of drying to 71.9, 88.9, 55.6, and 77.8% for L. monocytogenes-, S. aureus-, E. coli O157:H7-, and Salmonella-inoculated samples, respectively, and after an 8-h drying to 90.6, 94.4, 83.3, and 91.7% of samples, respectively. Significantly greater lethality was seen with higher dehydrator temperature and significantly lower with Teriyaki-marinated samples. Heating jerky dried in a home-style dehydrator for 10 min in a 135°C oven would be an effective way to help ensure safety of this product.