The effects of brine concentration and scalding on survival of some pathogens in urfa cheese: a traditional white-brined turkish cheese Hamdi Barbaros Ozer, 1 * Gu ¨ ven Uraz, 2 Ebru Beyzi-Yilmaz 2 & Ahmet Ferit Atasoy 1 1 Department of Food Engineering, Faculty of Agriculture, Harran University, Sanliurfa, Turkey 2 Department of Biology, Faculty of Art and Sciences, Gazi University, Ankara, Turkey (Received 9 October 2003; Accepted in revised form 22 February 2004) Summary The survival of Staphylococcus aureus (St. aureus), Bacillus cereus, Yersinia enterocolitica, Eschericia coli O157:H7, Shigella flexneri (Sh. flexneri) and Salmonella enteritidis (Sa. enteritidis) in urfa cheese (a traditional white-brined Turkish cheese) which was stored in brine concentrations varying from 12.5 to 17.5% (wt/v) was tested. Two sets of cheeses were made, namely scalded and unscalded cheeses (scalding was done by heating at 95 °C for 3 min). The variations in the counts of pathogenic colonies were monitored throughout a 90-day storage period at <10 °C. Results indicated that scalding caused statistically significant reductions in the colony counts of Y. enterocolitica, E. coli O157:H7, Sh. flexneri and Sa. enteritidis during the early periods of storage. In contrast, St. aureus and B. cereus were not generally affected by scalding and brine concentrations, although B. cereus in 17.5% (wt/v) brine was affected. In the unscalded cheeses, 12.5 and 15.0% (wt/v) brine concentrations seemed to be insufficient to eradicate the pathogenic organisms examined. Keywords Brining, cow’s milk, microbiological safety, pathogens, salt concentration, salt penetration, scalding, storage, white cheese. Introduction The popularity of traditional cheese varieties is increasing progressively all over the world and, except for those varieties which enjoy interna- tional recognition, some are still being produced traditionally on a small scale (Ozer et al., 2002a). Urfa cheese is a traditional white-brined cheese produced mainly in the southeast of Turkey. Apart from being a well-known cheese variety in Turkey, it is also exported to some Middle Eastern and Central Asian countries (Ozer et al., 2003). Urfa cheese is produced from either raw ovine or bovine milks or mixtures of both. However, since the production period of ovine milk in Turkey is rather short (c. 6–7 months), it is not always possible to extend urfa cheese production over the full year (Ozer et al., 2003). Therefore, the use of bovine milk in the manufacture of urfa cheese is a common practice. Additionally, the average daytime temperature in southeastern Turkey, where urfa cheese pro- duction is prevalent, is high. In the climatic and hygiene conditions that generally prevail, urfa cheese is often prone to microbial contamination. Cheese-borne salmonellosis, listeriosis and bru- cellosis are very common in this part of Turkey (Ozer et al., 2003). Previous studies showed that a significant percentage of urfa cheese samples collected from the local market were contamin- ated with Eschericia coli and Staphylococcus aureus and the counts of moulds/yeasts and coliforms were much higher than the upper limits of the international standards (Caglar et al., 1996; Sahan et al., 1998a,b; Ozer et al., 2000, 2002a; Yetismeyen & Yildiz, 2001). In order to minimize the risk of microbial contamination, *Correspondent: Fax: +90 414 247 4480; e-mail: bozer@e-kolay.net International Journal of Food Science and Technology 2004, 39, 727–735 727 doi:10.1111/j.1365-2621.2004.00837.x Ó 2004 Blackwell Publishing Ltd