Thermophilic Bacilli in Commercially Heat Treated Milks

S.N.M.khalid1, E.M.A.Ibrahim2 H.A.mohammed2, N.A.shawky1."


Thermophilic bacilli are an important group of contaminants in the dairy industry, as their presence in dairy products is an indicator of poor hygiene and high numbers are unacceptable to customers. A total of Fifty samples of pasteurized milk and UHT milk (25 of each) representing different brands available on the market were randomly collected in their retail containers from groceries, dairy shops and supermarkets in different localities at Menoufia governorate. These samples were examined bacteriologically for the presence of thermophilic aerobic spore forming bacilli. The highest incidence of thermophilic aerobic spore formers was in pasteurized milk followed by UHT milk with an incidence of 44% and 40% and with mean value of 1.3 x104 ± 8.6x103 and 9.4xl02± 3.9x102 C.F.U/ml, respectively. The most frequently isolated thermophilic (55°C) strains in examined samples were Bacillus licheniformis followed by Bacillus stearothermophilus.

Key words

Pasteurized milk, UHT milk, Thermophilic bacilli, Aerobic spore formers.