Methyl Red Indicator is recommended in IMViC test for detection of acid production from glucose fermentation.The Methyl red test is a biochemical test to detect acid producing organisms from glucose through the mixed acid fermentation pathway. 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 orange colour between yellow and red indicate negstive test. Escherichia coli ATCC 25922: Positive (Red colour observed) ; Enterobacter aerogenes ATCC 13048 Negative (Yellow colour observed)