Growth and survival of E.coli and S. Typhlmurlum in cultured buttermilk [electronic resource].

Includes references.

This study was carried out to Investigate growth and survival patterns of E.coli or S.typhlmurlum before and after fermentation process of cultured buttermilk product. Emphasis was given to evaluate the effect of level of inoculation, stage of inoculation (pre- or post- fermentation) and the storage temperature on the survival of both bacteria. When E.coIl at two levels (6 or 2 IogCFU/ml) was Inoculated separately Into the milk before fermentatlon, an Increase In the bacterial count of 1.5-3 folds was obtained for the two Inoculum's sizes and after 6, 12 hr of fermentation period respectively. The count then declined gradually for each when the fermented milks were stored at 25 or 5°C although the reduction was faster in all cases at 25°C than that at 5°C reaching undetectable levels within 18 and 30 days at two forementloned temperatures respectively for the high Inoculum's size. In contrast, samples with low E.coIi Inoculum showed a relatively fast disappearance of bacterium as It became undetectable after just 16 and 25 days of storage at 25 and 5 ̊c respectively.

Summary in Arabic.

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