EE Broth, Mossel

Intended Use

E E Broth, Mossel is used for selective enrichment of Enterobacteriaceae in bacteriological examination of foods. The composition and performance criteria of this medium are as per the specifications laid down in ISO 21528-1:2017 and ISO 11133:2014 /Amd. 2 : 2020 (E).

Composition**

Final pH (at 25°C): 7.2±0.2

**Formula adjusted, standardized to suit performance parameters

$ -Equivalent to Enzymatic digest of animal tissues

# -Equivalent to Ox Bile, purified

Directions

Suspend 43.46 gram in 1000 ml distilled water. Dispense 120 ml amounts in 250 ml flasks or 9 ml amounts in tubes. Stopper with cotton plugs or loose fitting caps. Heat in free flowing steam or boiling water for 30 minutes. Avoid overheating of the medium. DO NOT AUTOCLAVE.

Principle And Interpretation

EE Broth, Mossel was formulated by Mossel et al (1) and is recommended as an selective enrichment medium for Enterobacteriaceae by ISO (2) in bacteriological examination of foods and animal feed stuffs. EE Broth, Mossel (M287I) differs from EE Broth Mossel (M287) in the concentration of brilliant green used.

Peptone and dextrose allow the growth of most of the members of Enterobacteriaceae. Brilliant green and bile, purified are the selective agents for gram-positive bacteria. Lactose negative, anaerogenic lactose-positive or late lactose fermenting Enterobacteriaceae are often missed by the standard Coli-aerogenes test. To overcome this problem, lactose is replaced by dextrose in the media. Phosphates form the buffering system of the medium.

Type of specimen

Food samples

Specimen Collection and Handling

For food and dairy samples, follow appropriate techniques for sample collection and processing as per guidelines (2,3). After use, contaminated materials must be sterilized by autoclaving before discarding.

Warning and Precautions

Read the label before opening the container. Wear protective gloves/protective clothing/eye protection/ face protection. Follow good microbiological lab practices while handling specimens and culture. Standard precautions as per established guidelines should be followed while handling specimens. Safety guidelines may be referred in individual safety data sheets.

Limitations

1. Individual organisms differ in their growth requirement and may show variable growth patterns on the medium.
2. Each lot of the medium has been tested for the organisms specified on the COA. It is recommended to users to validate the medium for any specific microorganism other than mentioned in the COA based on the user’s unique requirement.

Performance and Evaluation

Performance of the medium is expected when used as per the direction on the label within the expiry period when stored at recommended temperature.

Quality Control

Appearance: Light yellow to greenish yellow homogeneous free flowing powder

Colour and Clarity of prepared medium: Emerald green coloured, clear solution without any precipitate

Reaction: Reaction of 4.35% w/v aqueous solution at 25°C. pH : 7.2±0.2

pH: 7.00-7.40

Cultural Response

Productivity: Cultural characteristics observed after an incubation at 35 ±1°C for 24±2 hours. Recovery is carried out on Violet Red Bile Agar

Selectivity: Cultural characteristics observed after an incubation at 35 ±1°C for 24±2 hours. Recovery is carried out on Tryptone Soya Agar

Key : * - Corresponding WDCM numbers

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 15-30°C. Use before expiry date on the label. On opening, product should be properly stored dry, after tightly capping the bottle in order to prevent lump formation due to the hygroscopic nature of the product. Improper storage of the product may lead to lump formation. Store in dry ventilated area protected from extremes of temperature and sources of ignition. Seal the container tightly after use. Product performance is best if used within stated expiry period.

Disposal

User must ensure safe disposal by autoclaving and/or incineration of used or unusable preparations of this product. Follow established laboratory procedures in disposing of infectious materials and material that comes into contact with sample must be decontaminated and disposed of in accordance with current laboratory techniques (4,5).

Reference

1. Mossel D.A.A., Vissar M. and Cornellisen A.M.R., 1963, J. Appl. Bact., 26(3):444
2. Microbiology of the food chain Horizontal method for the detection and enumeration of Enterobacteriaceae Part 1: Detection of Enterobacteriaceae. ISO 21528-1:2017
3. Microbiology of food,animal feeding stuffs and water- Preparation, production,storage and performance culture media, EN ISO 11133:2014 /Amd.2 : 2020 (E) .
4. Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
5. Jorgensen, J.H., Pfaller, M.A., Carroll, K.C., Funke, G., Landry, M.L., Richter, S.S and Warnock., D.W.(2015) Manual of Clinical Microbiology, 11th Edition. Vol.