The Importance of Geobacillus Spp. As Group of Bacterial Contaminates in the Dairy Industry

Abstract

Infant formulae are modern artificial substitutes for human breast milk. Formulas are designed for infant consumption, and are usually based on either cow milk or soy milk. Geobacillus represents aerobic or facultative anaerobic, neutrophilic, obligatory thermophilic, endosporeforming bacteria. A total of ninety random samples of milk powder, Infant milk powder and milk-cereal based weaning food (30 samples each) were purchased from different shops and pharmacies in Assiut city. Samples were examined for total thermophillic count, total spore count at 37°C and 55°C. The incidences of Geobacillus spp. and other bacillus spp. were also determined. The mean value of total thermophillic colony count/g was 10×10 3 ; 13×10 3 and 12×10 3 / g of examined dried milk powder, infant milk formulae and milk-cereal based weaning food samples, respectively at 37°C. While at 55°C, it was 1×10 2 and 7.6×10 2 /g in the same samples, respectively. Infant milk formulae were free. In addition, the mean of total spore count at 37 and 55°C were 22×10 2 and 10×10 3 /g in milk powder samples, respectively and 11×10 3 and 59×10 2 in milkcereal based weaning food samples and 13×10 3 in infant milk formulae at 37 °C. Geobacillus stearothermophilus could be isolated only from milk-cereal based weaning food in percentage of 16.7%. Some other Bacillus spp. could be detected at different temperatures with different percentages. Lipolytic and proteolytic activities of G. stearothermophilus were also evaluated.