Quantification and Antibiotic Susceptibility Profiles of Staphylococcus Aureus and Bacillus Cereus Strains Isolated From Biltong

Abstract

Biltong, an intermediate moisture meat product from South Africa, has been regarded as microbially safe because of its low water activity, low pH as well as the presence of curing salts. However, in this study, Staphylococcus aureus and Bacillus cereus counts from the biltong samples, in most cases, were above the infective dose limit and the South African national guidelines. Antimicrobial resistance of S. aureus and B. cereus on selected antibiotics was determined. Both species (S. aureus and B. cereus) were susceptible to oxytetracycline (74%; 80%), limcomycin (40%; 57%), bacitracin (65%; 58%), penicillin (53%; 63%), oxacilin (50%; 63%), methicillin (93%; 97%) and tetracycline (83%; 97%), respectively. S. aureus and B. cereus were resistant to nalidixic acid, and in general 47% and 33%, respectively, of the total tested strains of S. aureus and B. cereus were partially susceptible. It was encouraging to observe bacterial strains susceptible to antimicrobials used therapeutically in humans. However, the presence of nalidixic acid‐resistant strains of S. aureus and B. cereus on biltong is of concern as resistance might spread to other bacteria and ultimately consumers. PRACTICAL APPLICATIONS Biltong is a traditional South African spiced intermediate moisture meat (IMM) product with increasing popularity as a commodity worldwide. However, biltong production in different regions of South Africa (S.A.) is often a home industry, and the safety of this commodity is of concern. Therefore, biltong safety has to be ensured before it can be exported anywhere in the world. Currently, studies conducted in S.A. investigating the safety of biltong were mainly in the northern region. Thus, more studies are required to update the current knowledge on the prevalence of bacterial foodborne pathogens associated with this product as well as its potential in spreading antibiotic resistance. This is the first report on the presence of nalidixic acid‐resistant strains of S. aureus and B. cereus on biltong (produced in the central region of S.A.). This study contributes new knowledge to food processors in the central region of S.A. relating to the production of safe dried meat products.

Processing of South African biltong – A review

“…S. aureus was detected only in the study of Naidoo & Lindsay (2010a) with three strains of the 159 Staphylococcus isolates being confirmed as S. aureus. Another study showed that S. aureus in most biltong sampled exceeded 100 cfu.g -1 (Shale & Malebo, 2011). In South Africa, the commercial biltong industry uses the microbiological requirements as stated in the South African National Standards (SANS) 885.…”

Specificity of the production of traditional meat products and their safety using polish traditional cured meat products as example

“…The information concerning the microbiological quality of traditional cured meat products available in scientific literature is not always satisfactory. The results of studies on the presence of various pathogens in traditional cured meat products obtained by authors from different countries confirm that products of that type may sometimes be the cause of serious diseases in humans (Abrahim et al, 1998;Moore, 2004;Chevallier et al, 2006;Ferreira et al, 2006;Ferreira et al, 2007;Gounadaki et al, 2008;Mhlambi et al, 2010;Naidoo and Lindsay, 2010;Shale and Malebo, 2011;Rajkovic, 2012).…”

“…Products manufactured by applying traditional methods are frequently ready to eat (RTE) products that may represent a significant source of pathogens dangerous for health (Abrahim et al, 1998;Moore, 2004;Chevallier et al, 2006;Ferreira et al, 2006;Ferreira et al, 2007;Gounadaki et al, 2008;Mhlambi et al, 2010;Naidoo and Lindsay, 2010;Shale and Malebo, 2011;Rajkovic, 2012). Differences in the processing methods applied during production of traditional cured meat products may determine the differences in the final product quality.…”

“…The methods of making them, depending on the country and region of origin, are poles apart from the methods applied in production of their industrially produced equivalents. That specificity applies to the recipe, choice of raw material, spices and production conditions applicable in case of traditional cured meat products that, depending on the hygienic regimes applied may influence the microbiological quality, and conesquently their health safety, significantly (Abrahim et al, 1998;Moore, 2004;Chevallier et al, 2006;Ferreira et al, 2006;Ferreira et al, 2007;Gounadaki et al, 2008;Mhlambi et al, 2010;Naidoo and Lindsay, 2010;Martin et al, 2011;Shale and Malebo, 2011;Rajkovic, 2012).…”

Bioremediation of heavy metals from aquatic environment through microbial processes: A potential role for probiotics?

“…The six isolates were resistant to 30 µg of nalidixic acid. Previous studies have shown that 105 strains of Enterococcus and certain specific strains of Bacillus are resistant to this antibiotic [23].…”