Quality assurance of yoghurt during processing

Abstract

The present study was carried out to determine the critical points during processing of yoghurt, through examination of Acidity % and Storch's test to detect the efficiency of heat treated milk samples and Microbiological examination of samples collected weekly over a period of 7 months for TCC, Thermoduric, Total coliform, Faecal coliform, E. coli, Enterococci, S. aureus, Yersinia enterocolitica and Total yeast and mould counts. A total of 100 samples of raw milk, heat treated milk, inoculated milk and yoghurt (25 of each) in addition to 75 samples from worker’s hands, plastic packages and mixing vat (25 of each) were collected under strict hygienic conditions, also twenty five samples of yoghurt at the end of the expire date were collected and examined microbiologically. The obtained results concluded that the major sources of yoghurt contamination were raw milk, improperly cleaned and sanitized worker’s hands as well as the added starter culture. Finally, the public health and economic importance of the isolated organisms were mentioned.