Brilliant Green (Lactose) Bile Broth 2% (BGBB)

Test

Test

• If using a liquid sample, add 1 ml or less of the sample to 10 ml of the culture medium. If using 10 ml of the sample, add it to 10 ml of double concentrated culture medium. Be sure not to dilute the medium too much.
• If using solid food samples, soak a piece of the sample in water, and after preparing 1:10 dilutions of it, inoculate the sample into the culture medium at a ratio of 1:10. If adding larger volumes of the sample, use double concentrated culture medium.
• To identify E. coli bacteria, incubate the sample in the medium at 44 ± 1 degrees Celsius for 48 hours.
• To identify other coliforms, incubate the sample at 35 ± 2 degrees Celsius for 48 hours.

Results and Interpretation

Creating turbidity and changing the color of the environment to green-yellow are indicative of bacterial growth inside the culture tube. Gas formation in the Durham tube after 48 hours of incubation at 35±2 degrees Celsius indicates the presence of Klebsiella bacteria in the sample. If the result of the test is positive, confirmatory tests should also be performed.

Gas formation after incubation at 44±1 degrees Celsius is indicative of the presence of E. coli bacteria. To confirm, the sample can be cultured in Peptone Water and then tested for the production of indole.