Pathogens Associated with Biltong Product and Their in vitro Survival of Hurdles Used during Production

Biltong is a traditional South African spiced and dried, ready-to-eat meat product, and is an increasingly popular commodity worldwide. As few studies have evaluated its safety, this study evaluated 150 samples of South African biltong for aerobic bacteria, Enterobacteriaceae, coliforms, Escherichia coli, coagulase-positive Staphylococcus, Salmonella and Listeria monocytogenes. Selected strains of potential pathogens were further identified by use of 16S rDNA gene sequencing methods. In addition, the in vitro antimicrobial properties of each primary ingredient component of the biltong-making process was tested against selected bacterial isolates. Plate counts were the highest for aerobic bacteria (ca. 7 log CFU/g), followed by Enterobacteriaceae (ca. 4 log CFU/g), coliforms (ca. 3 log CFU/g), presumptive Staphylococcus (ca. 3 log CFU/g) and E. coli (ca. 1 log CFU/g) counts. All samples tested negative for Salmonella, while 2 samples tested positive for L. monocytogenes and 3 samples for enterotoxin-producing Staphylococcus strains. Results also showed that 25% of the isolates grew in the presence of up to 20% NaCl. Apple cider vinegar and brown spirit vinegar inhibited the growth of 63 and 50% of the isolates, respectively, while all 8 isolates (2 L. monocytogenes, 3 S. aureus and 3 S. pasteuri) showed the same growth patterns in the presence and absence of spices traditionally used in manufacturing biltong. Overall, strains of L. monocytogenes, Staphylococcus aureus and Staphylococcus pasteuri showed the most growth in all assays conducted. Results from this study highlighted biltong as a potential reservoir for foodborne pathogens, which have implications for foodborne illness.