Determination of microbial contamination sources for use in quality management of cheese industry: “Dil” cheese as an example

Abstract

The microbiological quality, safety and shelf-life of cheeses depend on manufacture and handling in an environment that meets basic standards for hygiene and the management of hygiene in the process. In this research contamination sources of “Dil” cheese during production in a local dairy plant in Bursa, Turkey were determined. Eighteen different control points (raw milk, pasteurized milk, heated curd, molded cheese before kneading, kneaded cheese, brine solution for kneading, thermophilic culture, rennet, calcium chloride solution, brine solution for cheese, cheese vat, workers hands, production room air, production room floor, production room wall, packaging material and packaged cheese) have been examined for the enumeration of total aerobic mesophilic bacteria, Staphylococci, Enterobacteriaceae, Salmonella spp., Escherichia coli, lactic acid bacteria, Pseudomonas spp. and yeast-moulds. It was determined that viability of lactic acid bacteria in thermophilic culture was not in high numbers and some contaminations to “Dil” cheese were detected from the starter culture. Brine solutions and rennet were contaminated with Staphylococci. Yeast and moulds in production room air were the major sources of contamination. Pasteurization and kneading in hot brine solution can eliminate some of the microorganisms but that was not sufficient in the production of Dil cheese. Finish cheese should meet specific hygienic standards, with respect to regulations post-contaminations to the cheese must be inhibited and a HACCP plan should be established during production.