ORIGINAL RESEARCH Occurrence of coagulase-positive Staphylococci, microbial indicators and physical–chemical characteristics of traditional semihard cheese produced in Brazil FABIANA R. VIANA, 1 AFONSO DE L. OLIVEIRA, 2 LUIZ S. CARMO 3 and CARLOS A. ROSA 3 * 1 Departamento de Cie ˆncia de Alimentos, Faculdade de Farma ´cia, C. P. 486, Universidade Federal de Minas Gerais, Belo-Horizonte, MG, Brasil, 2 Departamento de Tecnologia e Inspec ¸a ˜o de Produtos de Origem Animal, Escola de Veterina ´- ria, C. P. 567, Universidade Federal de Minas Gerais, Belo-Horizonte, MG, Brasil, 3 Departamento de Microbiologia, Instituto de Cie ˆncias Biolo ´gicas, C. P. 486, Universidade Federal de Minas Gerais, Belo-Horizonte, MG, Brasil *Author for correspondence. E-mail: carlrosa@icb.ufmg.br Ó 2009 Society of Dairy Technology Coagulase-positive Staphylococci and microbial indicators of the ‘Requeija ˜o do Norte’, a traditional semihard cheese, were surveyed in Brazil. Coagulase-positive Staphylococci were found in quantities of up to 9.4 log cfu ⁄ g. The coagulase gene was detected in isolates physiologically classified as coagulase- negative. The SEB and TSST-1 toxins were detected. Salmonella spp. were not detected. High levels of total and fecal coliforms (‡ 210 MPN ⁄ g) and moulds (‡ 6.48 log cfu ⁄ g) were found in most samples. The values of physical–chemical parameters and water activity showed the greatest variations. These results suggest a possible risk that this cheese may pose to consumers. Keywords Butter cheese, Coagulase-positive Staphylococci, Microbial analysis, Physical–chemical analysis, Requeija ˜o do Norte. INTRODUCTION ‘Requeija ˜o do Norte,’ also called butter cheese (Requeija ˜o de manteiga), is a traditional Brazilian cheese (FAO 1990; Brasil 1997) that is widely produced in the Southeastern and Northeastern regions of Brazil. The label ‘Requeija ˜o do Norte’ was based on technical standards of quality and identity (Brasil 1997, 2001b) by the Brazilian Ministry of Agriculture, Livestock and Supply. ‘Requeija ˜o do Norte’ is usually consumed in dif- ferent regions of the country and has a great social and cultural value, as well as economic signifi- cance. This cheese is produced on a traditional scale, in small farms by the producers (Nassu et al. 2003; Silva et al. 2006). In the North region of the State of Minas Gerais, the manufacturing process of this cheese involves the utilization of whole unpasteur- ized cows’ milk from different milking periods. After natural acidification, the cream is separated, the curd is heated at 45°C and the whey is removed. This curd is again heated at 90°C, and washed several times with water and fresh milk to reduce acidity levels. At the end of the process, salt is added to the curd along with a special butter, called ‘manteiga de garrafa’ (Brasil 2001b), which is mixed with the melted curd, poured into wooden moulds and air cooled. ‘Manteiga de garrafa’ is similar to butter oil, and it is obtained from cow milk cream following standard technique (Brasil 2001b). These cheeses are commonly commercialized without packaging, which often leads to microbial contamination (Guerra and Guerra 2003; Erkan et al. 2007). Pathogens such as Staphylococcus aureus, Escherichia coli and Salmonella spp. can contaminate this food and represent a potential risk to the health of the consumers (Leloir et al. 2003; Rodriguez et al. 2005; Erkan et al. 2007). The presence of coagulase-positive Staphylococcus and the occurrence of enterotoxins in food are impor- tant parameters for the evaluation of sanitary risk for the consumers (Aarestrup et al. 1995; Leloir et al. 2003). In view of the situation described above, this work on ‘Requeija ˜o do Norte’ was carried out to study the Staphylococcus coagulase-positive popu- lations, total and fecal coliforms, Salmonella spp., moulds and the physical–chemical characteristics of this cheese. In addition, the presence of Staphy- lococcal enterotoxins (SE) A, B, C, D and TSST-1 toxin was evaluated. MATERIAL AND METHODS Sample collection A total of 25 samples of ‘Requeija ˜o do Norte’ were collected during the period of September 2005 to April 2006. The samples were obtained at local 372 Vol 62, No 3 August 2009 International Journal of Dairy Technology doi: 10.1111/j.1471-0307.2009.00510.x