Influence of Yoghurt Starter Culture on Viability of Some Pathogenic Microorganisms in Yoghurt

摘要

This study was conducted to investigate the survival of Escherichia coli and Listeria monocytogenes during the storage period of laboratory manufactured yoghurt. Yoghurt was manufactured from laboratory pasteurized milk experimentally inoculated withE. coli ATCC 25922 and L. monocytogenes at an approximate population level of 6.5xl07 and 3xl07 CFU/mL. milk, respectively. The influence of starter culture on survival of the pathogenic microorganisms during the storage of laboratory manufactured yoghurt at 4°C for 15 days was studied. The obtained results revealed that the inoculated E. coli and L. monocytogenes couldn't be detected in yoghurt samples at 9th and 12th day of the storage period when the titratable acidity percentage was 0.9 and 1.36%,respectively. This inhibitory effect may be attributed to the higher acidity of yoghurt.