BTGN (Bile-Tolerant Gram-Negative bacteria) refers to a group of Gram-negative bacteria that can grow in the presence of bile salts. It is mainly used as an indicator of hygiene and contamination, especially in pharmaceutical, food, and microbiological testing.
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Prepare a 1 in 10 dilution using a minimum of 1 g of the product to be tested.
Use SoybeanโCasein Digest Broth as the diluent.
Mix the sample well and incubate at 20ยฐC to 25ยฐC for 2 to 5 hours to resuscitate any bacteria present without allowing significant multiplication. - ๐๐๐ฌ๐ญ ๐๐จ๐ซ ๐๐๐ฌ๐๐ง๐๐ ๐จ๐ ๐๐ข๐ฅ๐-๐๐จ๐ฅ๐๐ซ๐๐ง๐ญ ๐๐ซ๐๐ฆ-๐๐๐ ๐๐ญ๐ข๐ฏ๐ ๐๐๐๐ญ๐๐ซ๐ข๐
Use the equivalent of 1 g of the product (prepared as described above) to inoculate Enterobacteria Enrichment Broth(EEB)
Incubate at 30ยฐC to 35ยฐC for 24 to 48 hours.
Subculture on plates of Violet Red Bile Glucose Agar.
Incubate again at 30ยฐC to 35ยฐC for 18 to 24 hours.
Interpretation: The product passes the test if no colonies are observed on the plates.
Quantitative Test for Bile-Tolerant Gram-Negative Bacteria
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*Inoculate suitable amounts of Enterobacteria Enrichment Broth with different dilutions of thesample to represent 0.1 g, 0.01 g, and 0.001 g (or 0.1 mL, 0.01 mL, and 0.001 mL) of the product.
*Incubate at 30ยฐC to 35ยฐC for 24 to 48 hours.
*Subculture each enriched sample onto Violet Red Bile Glucose Agar plates.
*Incubate again at 30ยฐC to 35ยฐC for 18 to 24 hours.
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*Growth of colonies indicates a positive result. - *Record the smallest quantity of product that shows a positive result and the largest quantity that shows a negative result.