Validation of Ground-and-Formed Beef Jerky Processes Using Commercial Lactic Acid Bacteria Starter Cultures as Pathogen Surrogates

Abstract

Beef jerky has been linked to multiple outbreaks of salmonellosis and Escherichia coli O157:H7 infection over the past 40 years. With increasing government scrutiny of jerky-making process lethality, a simple method by which processors can easily validate the lethality of their ground-and-formed beef jerky process against Salmonella and E. coli O157:H7 is greatly needed. Previous research with whole-muscle beef jerky indicated that commercial lactic acid bacteria (LAB) may be more heat resistant than Salmonella and E. coli O157:H7, suggesting the potential use of LAB as pathogen surrogates. Of six commercial LAB-containing cultures evaluated for heat resistance in ground-and-formed beef jerky, Saga 200 (Pediococcus spp.) and Biosource (Pediococcus acidilactici) were identified as consistently more heat resistant than Salmonella and E. coli O157:H7. Six representative ground-and-formed beef jerky commercial processes, differing widely in lethality, were used to identify an appropriate level of LAB reduction that would consistently indicate a process sufficiently lethal (≥5.0-log reduction) for Salmonella and E. coli O157:H7. Both Saga 200 and Biosource consistently predicted adequate process lethality with a criterion of ≥5.0-log reduction of LAB. When either LAB decreased by ≥5.0 log CFU, processes were sufficiently lethal against Salmonella and E. coli O157:H7 in 100% of samples (n = 39 and 40, respectively). Use of LAB as pathogen surrogates for ground-and-formed beef jerky process validation was field tested by three small meat processors, who found this technique easy to use for process validation.