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low aw and high salt concentrations (7, 8), and it would therefore be less likely to harbor and support its growth. However, strains of L. monocytogenes are often associated with raw poultry meat (7, 15). In this study, this pathogen was isolated from chicken biltong. The presence of these strains could be attributed to the contamination of biltong prior to and at production, and distribution and within the retail environments of this commodity, due to the ubiquitous prevalence of this foodborne pathogen (15).

Effect of in-process hurdles applied to biltong on selected foodborne pathogens
Overall, strains of L. monocytogenes (n = 2), S. aureus (n = 3) and S. pasteuri (n = 3) showed growth in most of the assays conducted. Seven of the 8 isolates grew in the presence of 15% NaCl. In addition, it was evident that isolates belonging to the Staphylococcus genus were the only isolates that showed growth at ≥ 15% NaCl. This was not unexpected, as several strains of Staphylococcus have been shown to survive in environments containing high salt concentrations (9). Both the plate and the broth method used in this study showed the same qualitative growth patterns. Only strains of L. monocytogenes grew at 4ºC, while all other isolates grew optimally in the temperature range of 25–37ºC. In addition, none of the 8 isolates tested showed growth at 45ºC. It is important to note that during the biltong manufacturing process, meat slices are often marinated at refrigeration temperatures of ca. 4ºC. Although this temperature does not favor the growth of 80% of the isolates evaluated in this study, it did support the growth of strains of L. monocytogenes. Such findings are not uncommon, as strains of L. monocytogenes are known to proliferate at refrigeration temperatures (15). Results from this study showed that all isolates were inhibited by undiluted glacial acetic acid (positive control), while the apple cider vinegar and brown spirit vinegar inhibited the growth of only some strains. It has previously been reported that acetic acids, such as vinegars and wines, possess bacteriostatic and bacteriocidal properties (13). For example, a study conducted by Entani and associates (13) showed that even at

the lowest concentrations, vinegar had bacteriocidal properties against Escherichia coli O157:H7. Although apple cider vinegar exhibited enhanced antimicrobial properties compared to brown spirit vinegar, both vinegars were inadequate to cause complete growth inhibition of foodborne pathogenic and enterotoxin producing strains. Vinegar marination is an important component of the biltong manufacturing process, and survival of potential foodborne pathogens during this process is cause for concern. Furthermore, results also showed that all 8 isolates exhibited the same growth patterns in the presence and absence of traditionally used biltong spice. Spices such as black pepper and coriander, which are the predominant spices in the traditional biltong spice mix, are known to possess weak to mild antimicrobial properties in general (6, 11).

CONCLUSION
This study highlighted biltong at point-of-sale as a potential vehicle for foodborne pathogens and showed that S. aureus, S. pasteuri and L. monocytogenes may also survive the hurdles used during biltong production. However, the findings in this study were based on in vitro results. Thus the question remains as to whether the same foodborne pathogens are able to survive the biltong manufacturing process in situ, a question which is currently being investigated.

ACKNOWLEDGMENTS
The authors thank the University of the Witwatersrand and the Friedel Sellschop Award, and Carnegie Corporation Transformation Programme for project funding, as well as the National Research Foundation, for student funding.

REFERENCES
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