Fate of Salmonella enteritidis and Salmonella typhimurium during the fermentation of ergo, a traditional Ethiopian sour milk.

The growth potential of Salmonella enteritidis and Salmonella typhimurium in milk in smoked and non-smoked containers and their inhibition by lactic acid bacteria was determined. In the absence of lactic acid bacteria, both Salmonella strains could grow to the level of 10(8) cfu/ml within 12 h. Smoking of containers significantly retarded Salmonella growth only until 12 h. Growth of lactic acid bacteria in souring milk retarded growth of Salmonella strains and complete inhibition was observed between 48 and 60 h at pH and titratable acidity values of 3.7 and 0.70%, respectively. The synergistic effect of lower pH, acids and smoking was important in the complete inhibition of the test organisms. Although ergo was preferably consumed after 24 h of fermentation, the Salmonella strains were not completely inhibited at this time. Thus, traditional making of ergo by the natural fermentation of raw milk could be hazardous to health. The use of a three-day old ergo as a starter for boiled milk is recommended to ensure the wholesomeness of ergo.