EFFECT OF YOGHURT STARTER LACTIC ACID BACTERIA ON

The growth of lactic acid bacteria of yoghurt culture Str.salivarius sub-sp thermophilus (Str. thermophilus) and Lacto bacillus delrueckeii sub-sp bulgaricus (Lacto. bulgaricus)in milk inhibited the growth of vegetative cells of B .cereus and spores that resisted the high heat treatment which was isolated from raw milk and prevented the B .cereus from producing the enterotoxins in yoghurt . The B .cereus did not affect the growth of yoghurt starter culture, also the rate of acid development in yoghurt was not affected in the presence of B. cereus. The poisoning by this bacteria did not happen in dairy product when number decreased to less than 106 c.f.u. /ml .