Double Lactose Bile Salt Broth (With Neutralizer) for Fecal Coliform Detection in Cosmetics
This selective broth medium is specially developed for the detection of fecal coliforms in cosmetic products. It contains lecithin and Tween 80 as neutralizers to eliminate the bacteriostatic effect of cosmetic preservatives, enabling accurate recovery of target bacteria.
Formula Composition (per Liter)
| Ingredient |
Content |
| Peptone |
40.0 g |
| Pig bile salt |
10.0 g |
| Lactose |
10.0 g |
| Bromocresol purple |
0.02 g |
| Lecithin |
2.0 g |
| Tween 80 |
14.0 g |
| Final pH |
7.4 ± 0.1 at 25 ℃ |
Verification Principle
Peptone provides carbon and nitrogen sources to support bacterial growth. Pig bile salt suppresses the growth of Gram-positive bacteria. Lactose is the fermentable carbohydrate for coliform group. Lecithin and Tween 80 neutralize preservatives in cosmetics and act as dispersants for emulsion samples. Bromocresol purple is a pH indicator, turning yellow under acidic conditions and purple under alkaline conditions.
Directions for Use
Weigh 76.0 g of the medium powder, heat and dissolve in 1000 mL distilled water, dispense into test tubes with small inverted Durham tubes. Autoclave at 115 ℃ for 20 minutes and reserve for later use.
Microbial Performance Test for Double Lactose Bile Salt Broth (With Neutralizer)
Prepare the medium following the instructions. Inoculate specified quality control strains and incubate aerobically at 44 ± 0.5 ℃ for 24–48 hours.
