Effect of using probiotic starters on the viability of some pathogenic bacteria in kareish cheese [electronic resource].

Includes reference.

The antagonistic effect of yoghurt starter (L.bulgaricus and S. thermophilus), yoghurt plus probiotic bacteria namely L.acidophilus, B. bifidum and L. casei against the pathogenic bacteria Bacillus cereus, Staphylococcus aureus and Escherichia coli 0157: H7 was studied on Kareish cheese. In the control treatments, milk was manufactured to Kareish cheese without starter and coagulated with rennet, one of them without pathogenic bacteria and in the other three controls, milk was contaminated with the three pathogenic bacteria. In the experimental treatments milk was also contaminated with the three pathogens and manufactured to Kareish cheese by using four kinds of starter, for each microbe as follows, yoghurt 3%, 1% yoghurt plus 2% of each of the three probiotic starters. The count of pathogenic bacteria was estimated in the controls and treatments during 15 days as well as titratable acidity and inhibition ratio. In the controls the number of pathogenic bacteria increased throughout 15 days of storage period while their growth was effectively inhibited in all treatments. Also when yoghurt starter mixed with probiotic starters the inhibition ratio was increased especially B. bifidum against Staph. aureus (not detected after 9 days), B. bifidum and L. acidophilus towards B. cereus (12 days) and all the three probiotic towards E.coli(15 days).it is recommended to use probiotic bacteria in fermented dairy products with the traditional cultures to produce healthy and safe products.

Summary in Arabic.

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