Death of Salmonella serovars, Escherichia coli O157 : H7, Staphylococcus aureus and Listeria monocytogenes during the drying of meat: A case study using Biltong and Droewors

Biltong and droëwors are ready-to-eat dried seasoned beef strips and sausages, respectively. Procedures to meet process lethality requirements for these products have not been validated. The fate of Salmonella serovars, Escherichia coli O157 : H7, Staphylococcus aureus, and Listeria monocytogenes was evaluated during the manufacture and vacuum-packaged storage (7 days at 20-22C) of three lots each of biltong and droëwors. Acid-adapted pathogens were used as inocula (ca. 7 log CFU per sample for each pathogen). The biltong manufacturing process reduced pathogen levels from 1.2 to 3.8 log CFU (S. aureus and L. monocytogenes, respectively). Less lethality was achieved in making droëwors, probably because of the higher fat content. The manufacturing processes for biltong and droëwors achieved significant lethality. Combined with additional intervention steps and/or raw material testing, the processes would achieve mandated levels of pathogen destruction. The results of our experimental trials can be applied to commercial dried meat products with water activity, MPR, pH and % water-phase salt at least as restrictive as our trial products. It was clear from our results that drying of seasoned beef strips or sausage would result in significant reduction in numbers for all four pathogens tested.