Products

Principle:

M-Endo Agar, LES is a modification of the original medium and is formulated as per McCarthy et al of Lawrence Experimental Station (LES). M-Endo agar is composed of tryptone, peptone, tryptose, yeast extract, lactose, Dipotassium phosphate monobasic and dibasic, sodium chloride, sodium deoxycholate, sodium lauryl sulphate, sodium sulphite, basic fuchsin and agar. tryptone, peptone, tryptose, yeast extract, is source of nitrogenous substances and other essential growth nutrients for the organisms. Lactose is carbon source and phosphate are act as buffering agent. Sodium chloride maintains osmatic equilibrium of medium. Sodium deoxycholate, Sodium sulphite and basic fuchsin is selective agent inhibit the growth of gram positive bacteria. Coliforms give pink color colonies due to lactose fermentation while lactose nonfermenters produce colorless colonies. In the first step of enrichment, cotton absorbent pad is impregnated with Lauryl Sulphate Broth. Aseptically transfer water sample through the membrane filter, placed on it and incubated without inverting for 2.0 hours at 35°C in a humid atmosphere. After incubation, the membrane

filter is aseptically transferred to the M-Endo Agar plate and incubated at35°C for 24 hours. Otherwise, membrane filter pad can be placed inside the lid of Petri plate of M-Endo Agar and then soaked with 2.00 ml Lauryl Sulphate Broth and incubated for 1 - 1½ hours at 35°C. In the second step, the prepared membrane filter is kept directly on the agar surface and incubated as described above. Presumptive coliforms produce golden green colonies with metallic sheen within 24 hours of incubation. Coliform density calculation: Note the coliform density in terms of total coliforms/100 ml. Extrapolate the count using membrane filters with 20-80 coliform colonies but not more than 200 of all types per membrane.

The formula for calculating the count is as follows:

Total coliform colonies/100 ml = coliform colonies /ml of sample filtered x 100

Use: Recommended for enumeration of coliforms in water using a two-step membrane filtration technique.

Ingredients:

Directions: Dissolve 25.00 grams in 1000 ml distilled water. Boil to dissolve the medium completely and sterilize by autoclaving at 15 lbs pressure (121°C) for 15 min, cool it to 42-45 °C and inoculate test sample aseptically.

Storage and Shelf Life: The product is highly hygroscopic; keep the container tightly closed at all times and store it properly as per the conditions mentioned on the label. The declared expiry is valid only when stored as per the conditions mentioned on the label.

Note: Sterilize media immediately after reconstitution.

Disposal: To avoid the contamination or propagation of any hazardous microbes the used, unusable or modified preparation of this product must be disposed after autoclaving after completion of task.