Methyl Red Indicator is supplied by Micromaster. It is available in the form of a greenish yellow coloured solution. It is red at pH 4.4 and yellow at pH 6.2 at 25 C. This product should be stored between 10-30C in a tightly closed container.

Quantity provided: 100 ml/bottle

Methyl red is a pH indicator with a range between 6.0(yellow) and 4.4(red). It is used in IMViC test for detection of acid production from glucose fermentation. Methyl red test is a quantitative test for acid production, requiring positive organisms to produce strong acid (lactic, formic) from glucose through the mixed acid fermentation pathway. Since many species of Enterobacteriaceae may produce sufficient quantities of strong acid that can be detected by methyl red indicator during the initial phases of incubation. Only organisms that can maintain this low pH after prolonged incubation (48-72 hours) and overcoming the pH buffering system of the medium can be called as methyl red positive. The development of stable red colour in surface of the medium indicates sufficient acid production to lower pH to 4.4 and constitutes positive test. While other organisms may produce lesser quantities of acid from test substrate, an intermediate orange colour between yellow and red may developed,this indicate negative test.