ゼリー飲料および固形化成分を含有する粉末清涼飲料の細菌試験法の問題点とその改善法の検討

抄録

Examination methods for coliform bacteria in jelly beverage and powdered beverage with solidified ingredients, and standard plate counts in powdered beverage with solidified ingredients were investigated. In the examination of coliform bacteria in jelly beverage using Japanese official methods for beverage and powdered beverage, it was demonstrated that gas production by Escherichia coli in 10 ml of double strength lactose broth with bromothymol blue (LB) with 10 ml of jelly beverage was incorrectly judged on occasion. Gas, however, was successfully trapped in 100 ml of LB instead of 10 ml of double strength LB. In the examination of the powdered beverage with solidified ingredients, 100-fold diluted homogenate were prepared instead of 10-fold diluted homogenate to weaken solidification because 10-fold diluted homogenate had a high solidification. For coliform bacteria examination, gas was successfully trapped in 100 ml of double strength LB with 100 ml homogenate, and the detection limit was the same as that by Japanese official methods. For standard plate count examination, it, however, was difficult to count the colonies by pour plate culture method, and more investigation is needed in the future.