Abstract
The presumptive test for the thiamine decomposing bacteria on nutrient agar plate is difficult. If there is a differential medium, it would be very advisable to identify the thiamine decomposing bacteria on presumptive test. In this point, the studies on colonies of the thiamine decomposing bacteria and other enteric bacteria on the media which contain soluble starch and pH indicator were made. In the soluble starch plate, Bacillus thiaminolyticus yields yellow colonies, while the other bacteria, such as Shigella flexneri, Escherichia coli 119,Salmonella paratyphiA, Aerobacter aerogenes, Bacillus subtilis, Proteus OX 19,etc. have not.
