Determination of microbiological contamination sources during Turkish white cheese production

This study has been conducted to determine the microbiological contamination sources during production of white cheese in a local dairy plant, Bursa, Turkey. Twenty nine different control points or sample types (raw milk, pasteurized milk, milk in cheese vat, curd, moulded cheese before salting, moulded cheese after salting, cheese at cold holding and vacuum packaged cheese; samples from starter culture, rennet, calcium chloride solution, brine, cheese vat, cheese cloth, polyethylene separator sheet, milk stirrer, curd cutting knife, side pressure plate, upper pressure plate, moulded cheese cutting knife, cheese tray, packaging material used during production; workers’ hands, cold room and production room air, floor, wall, and potable water) have been examined for the enumeration of total aerobic mesophilic bacteria, staphylococci, coagulase positive staphylococci, Enterobacteriaceae, enterococci, coliforms, Escherichia coli, psychrophilic bacteria, and yeast and molds. We determined: starter culture as the possible contamination source of coagulase positive staphylococci, enterococci and psychrophilic bacteria; brine and upper pressure plate as the contamination source for staphylococci; floor and packaging material as the contamination source of psychrophilic bacteria; cheese vat, cheese cloth and curd cutting knife as the contamination source of total aerobic mesophilic bacteria; cold room and production room air as the contamination sources for yeast and molds.