Methyl red test

The methyl red test is based on the fact that all Enterobacteriaceae can ferment glucose and produce pyruvate during the decomposition of glucose. In the further decomposition, due to different pathways of sugar metabolism, a large amount of acid such as lactic acid, succinic acid, acetic acid and formic acid can be produced. The product can test the principle that the pH value of the culture medium can be lowered to below pH 4.5 and the methyl red indicator becomes red.