VLD 421: Veterinary Clinical Biochemistry and Laboratory Diagnosis-II (0+1)

SUGAR FERMENTATION TEST

Principle

• In the process of bacterial metabolism, the carbohydrates are attacked by the bacterial enzymes to produces acid and gas in the test media. This can be identified by using pH indicators (acid) and Durham’s tube (Gas)

Methodology

• Prepare 1% peptone water with Andrade’s or Phenol red indicator and 1% sugar
• Durham ’s tube is inverted in the sugar medium to observe the gas production.
• Inoculate the organism into 5 ml of the sugar medium and incubate at 37⁰C for 1 week.

Result

• Acid production by fermentation of sugars is indicated by Yellow (Phenol red) and Pink (Andrade’s) colour development in the test media.