Evaluation of Escherichia Coli and Salmonella spp. in Yoghurt Processing in Khartoum State – Sudan

Abstract

The aim of this study was to investigate the total viable bacterial load in the different stages of yoghurt processing, and to isolate and identify Salmonella spp. and Escherichia coli during the period from November 2015 to October 2017 in yoghurt production unit in Khartoum- Sudan. Sixty samples were collected at different six stages of the processing (Whole milk, pasteurized milk, cold pasteurized milk, milk +starter, after incubation and Cold Yoghurt)where the isolation and identification of the two types of bacteria (Salmonella spp. and Escherichia Coli ) were investigated. The results revealed that the Total Viable Count (T. V. C.) indicated the highest level of contamination in Whole Milk stage ( Mean (Log.CFU/ml) = 6.93±0.20 in which the positive samples for Salmonella spp. 2(3.84)% and Escherichia coli . 10(19.16)% while the lower contamination level was at hot pasteurized milk stage ( Mean (Log-CFU/ml)=6.34±0.07 in which the positive samples for Salmonella spp. 2(3.6) %, and Escherichia coli . 3(5.4)%.The statistical analysis of the result revealed there was a significant difference at (P ≤0.05) of total viable bacterial count in different processing stages of yoghurt production The study concluded that, contamination was reported in all stages of yoghurt production processes with Escherichia Coli and Salmonella spp.