Behavior of Bacillus Bacteria in Coffee, Black Tea, and Green Tea Drinks

The behavior of heat-resistant spore-forming bacteria (Bacillus cereths, B. subtilis, and B. coagulans) during storage in various coffee, black tea, and green tea drinks was investigated. Spores of each Bacillus species were inoculated into each drink. After heat pasteurization at the lowest condition under the Food Sanitation Act for soft drinks with >= pH 4.6 (85 degrees C, 30 min), viable bacterial counts under each optimum growth temperature were measured for two weeks. Viable counts of the three species of Bacillus inoculated into coffee. black tea, and green tea without milk decreased, whereas B. cereus and B. subtilis increased in coffee and black tea drink with milk. These results suggest that the commercial sterility of coffee, black tea, and green tea drinks without milk can be guaranteed with pasteurization of 85 degrees C for 30 min, even if the Bacillus species is present. (Received Mar. 30, 2012 : Accepted Jul. 23. 2012)