ENTEROTOXIN‐PRODUCING STAPHYLOCOCCUS STRAINS ASSOCIATED WITH SOUTH AFRICAN BILTONG AT POINT OF SALE

Abstract

ABSTRACT This study assessed the presence of Staphylococcus strains associated with the ready‐to‐eat meat product, biltong, (n = 26), at point of sale. Traditional beef, spiced/flavored beef, chicken and venison biltong varieties were purchased from local retailers, butcheries and street vendors. Samples were prepared for aerobic counts, yeast counts and presumptive Staphylococcus counts using standard spread plating techniques. Presumptive Staphylococcus aureus strains were selected using Pake's disk and characterized using a dichotomous key. Eleven of these strains were selected and further identified using 16S rDNA sequence analysis. Five of these, representing different species of Staphylococcus, were tested for enterotoxin production using the Set‐RPLA toxin detection kit. Of the three biltong varieties, the chicken and venison consistently showed the highest counts across all types of media used (ca. 7 log colony forming units (cfu)/g), while the spiced biltong varieties generally showed lowest counts (ca. 5.5 log cfu/g). All 11 strains were identified by 16S rDNA sequence analysis as members of the Staphylococcus genus. Of these, five clustered with other Staphylococcus equorum strains, two with the Staphylococcus saprophyticus/Staphylococcus xylosus group, two with Staphylococcus succinus isolates and one each with Staphylococcus piscifermentans or S. aureus clusters. Enterotoxins staphylococcal enterotoxin B (SEB) and staphylococcal enterotoxin D (SED) were produced by two of the isolates indicating foodborne illness implications.PRACTICAL APPLICATIONS Biltong is a South African dried meat commodity which is a national favorite. However, very few studies have been conducted on the microbiological safety of biltong, as it has traditionally been seen as “safe” due to a low water activity (0.77) and pH (5.5). This preliminary study identified the presence of various strains of Staphylococcus associated with biltong product at point of sale in South Africa, and showed that some of these isolates, including Staphylococcus aureus and Staphylococcus equorum strains, held foodborne illness implications as they produced staphylococcal enterotoxins. This is the first such report on the presence of enterotoxin‐producing Staphylococcus in biltong and contributes new knowledge to food processors in South Africa relating to production of safe dried meat products.