Methyl red test
The methyl red test determines the ability of organism to acidify
a phosphate buffered glucose-peptone medium to pH 4.4 or below
and culture was inoculated and incubated at room temperature for
48 h. After incubation, two drops of methyl red solution, prepared
by dissolving 0.1 g of methyl red in 300 mL ethyl alcohol and
200 mL distilled water, was added to the inoculated medium. A red
color indicates positive reaction while yellow color signifies negative
reaction.