Soyabean Casein Digest Medium w/ 0.5% Soya Lecithin

Intended Use

Soyabean Casein Digest Medium with 0.5% Soya Lecithin is used for sanitary examination of surfaces.

Composition**

Final pH ( at 25°C): 7.3±0.2

**Formula adjusted, standardized to suit performance parameters

Directions

Suspend 35.0 grams in 1000 ml distilled water. Heat if necessary to dissolve the medium completely. Sterilize by autoclaving at 15 lbs pressure (121°C) for 15 minutes. Cool to 25°C and store in a cool dark place preferably below 25°C.

Principle And Interpretation

Soyabean Casein Digest Medium with 0.5% Soya Lecithin is used for the detection of microorganisms on surfaces of sanitary importance.

Casein enzymic hydrolysate and papaic digest of soyabean meal provide essential nutrients. Dextrose serves as source of fermentable carbohydrate for the energy production. Sodium chloride maintains osmotic balance while dipotassium phosphate provides buffering capacity. Lecithin is incorporated to neutralize any residual disinfectant activity (1, 2, 3).

Quality Control

Appearance: Cream to yellow homogeneous free flowing powder

Colour and clarity of prepared medium: Light yellow coloured clear to slightly opalescent solution.

Reaction: Reaction of 3.5% w/v aqueous solution at 25°C. pH : 7.3±0.2

pH: 7.10-7.50

Cultural Response

M1529: Cultural characteristics observed after an incubation at 30-35ºC for 24-48 hours (fungal cultures incubated at 20-25ºC for 2-7 days).

Storage and Shelf Life

Store below 30°C in tightly closed container and the prepared medium at 2 - 8°C. Use before expiry date on the label.

Reference

1. McGowan. In Lennette et al (Eds.), 1985, Manual of clinical microbiology, 4th ed. American Society for Microbiology, Washington, D.C.
2. Speck M. (Ed.), 1984, Compendium of Methods For The Microbiological Examination of Foods, 2nd ed. APHA, Washington D.C.
3. Quisno, Gibby and Foter. 1946. Am. J. Pharm. 118: 320.