Description
Phenol Red Broth Medium is formulated as per Vera (8) and is recommended to determine the fermentation reaction of carbohydrates for the differentiation of microorganisms (1,2,6). Phenol Red Broth Medium with various carbohydrates serves as a differential medium by aiding in differentiation of various species and genera by their ability to ferment the specific carbohydrate, with the production of acid or acid and gas (7). Phenol Red Dextrose Broth is used to study dextrose fermentation in various bacteria.
Proteose peptone and HM peptone B serve as sources for carbon and nitrogen. Sodium chloride is the osmotic stabilizer. Phenol red is the pH indicator, which turns yellow at acidic pH i.e. on fermentation of dextrose. Gas formation is seen in Durhams tubes. All of the Enterobacteriaceae grow well in this medium. In addition to producing a pH colour shift, the production of mixed acids, notably butyric acids, often results in a pungent, foul odour from the culture medium (5).