Description
Amyl L-S Differentiation Medium, AM 92, is compounded according to the formula developed by Eloy1, for enumerating and differentiating between Lactobacillus bulgaricus and Streptococcus thermophilus, organisms responsible for the controlled fermentation of milk (at 43°C) to produce yoghurt.
The medium incorporates beef extract, peptones, yeast extract and glucose to provide nutrients, vitamins and growth factors for bacterial metabolism. Skim milk is present to indicate the casein digestive capabilities of the organisms while sodium chloride maintains osmotic equilibrium. Reducing conditions are enhanced by the sulphur containing amino acid, cysteine and triphenyl tetrazolium chloride (TTC), provides visual confirmation of the presence of redox conditions and bacterial metabolism.
