Determination of contamination sources during the manufacturing of yoghurt

Abstract

This study aimed to investigate the critical control points for the contamination in a factory experiencing a problem with coliform bacteria and Escherichia coli, and to prevent economic losses and also to protect public health by facilitating production under hygienic conditions. Samples were taken from a total of 20 control points, which involved every stage of production from the beginning to the end, including milk, all equipment, surfaces, air, hands of staff and water; yoghurt samples were taken on the same day. Microbiological analysis of all samples was performed to determine total mesophilic viable count, micrococci-staphylococci, coagulase positive staphylococci, enterobacter, coliform bacteria, E. coli, enterococci, yeast and moulds. The evaporators, milk pump, and hands of staff were determined to be critical control points for enterobacter and coliform bacteria, particularly E. coli, in the factory, but there was no risk after the training and checking of the personnel for hygiene. It was shown that factories having various contamination sources were inevitable because of the unstandardized design of milk factories in Turkey. It is necessary to determine critical control points in all factories and organized auto-control systems in order to eliminate or at least minimize the risks.