ANTIBIOTIC ASSAY MEDIUM NO. 41 (VEG.)

Antibiotic Veg Assay medium No. 40 is prepared by incorporation of vegetable peptones in place of animal peptones, making the medium, BSE-TSE risks free. This medium can be used for the same purpose of Antibiotic Assay Medium No. 41. It is recommended for turbidimetric microbiological assay of thiostreptone, a polypeptide antibiotic. Grove and Randall have elucidated the antibiotic assays and media in their comprehensive treatise on antibiotic assays.
Turbidimetric antibiotic assay is based on the change or inhibition of growth of test microorganisms in a liquid medium containing a uniform concentration of an antibiotic. After incubation of the test organism in the working dilutions of the antibiotics, the amount of growth is determined by measuring the light transmittance using spectrophotometer. The concentration of antibiotic is determined by comparing amounts of growth obtained with that is given by the reference standard solutions. Use of this method is appropriate only when test samples are clear.

for the microbiological assay of Thiostrepton using Streptococcus faecium as the test organism