Soyabean Casein Digest Agar Plate with 0.5% Lecithin and 2% Polysorbate 80 and 1% Glycerol (g-irradiated) (Tryptone Soya Agar Plate w/Lecithin and Polysorbate 80) is supplied by HiMedia. It contains sterile ready prepared media in 55mm scored plates. This light to medium amber coloured product has a pH in the range of 7.1 to 7.5. Soyabean Casein Digest Agar is widely used for determining efficiency of sanitization of containers, equipments, surfaces, water miscible cosmetics etc. It is advisable to store this product between 15-25C. Composition (in gm/L) is as follows:

Casein enzymic hydrolysate (15.00)

Papaic digest of soyabean meal (5.00)

Sodium chloride (5.00)

Lecithin (0.70)

Polysorbate 80 (Tween 80) (5.00)

Agar (15.00)

Tryptone Soya Agar with Lecithin and Polysorbate 80 is commonly used in RODAC (Replicate Organism Detection and Counting) plates for the detection and enumeration of microorganisms present on surfaces of sanitary importance. Casein enzymic hydrolysate and papaic digest of soyabean meal supply nitrogenous compounds and other nutrients which are essential for microbial replication. Lecithin, polysorbate 80 (Tween 80) and thiosulphate neutralize the activity of antimicrobial agents. They neutralize quaternary ammonium compounds and parahydroxy benzoates too. Sodium thiosulphate can neutralize mercurial compounds, halogens, aldehydes etc. Histidine acts as a reducing agent. Testing samples from areas before and after the treatment with disinfectant can be used to evaluate cleaning procedures in environmental sanitation. The presence and number of microorganisms is determined by the appearance of colonies on the agar surface.