EE Broth, Mossel

Intended Use

Recommended for selective enrichment of Enterobacteriaceae in the bacteriological examination of food.

Composition**

Final pH (at 25°C): 7.2±0.2

**Formula adjusted, standardized to suit performance parameters # Equivalent to Oxgall

Directions

Suspend 45.01 grams in 1000 ml purified /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 (100°C) 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 and is recommended as an enrichment medium for Enterobacteriaceae in bacteriological examination of foods (3) and animal feed stuffs (8). EE Broth, Mossel differs from EE Broth, Mosssel in the source of carbon. This medium is provided with additional buffering action due to increased concentration of disodium phosphate and Bile is replaced with oxgall. Tryptose and dextrose allow the growth of the most of the members of Enterobacteriaceae. Brilliant green and oxgal or ox-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 lactose is replaced by glucose in the media.

Cells damaged while drying or by low pH are resuscitated in well-aerated Tryptone Soya Broth (M011) for 2 hours at 25°C prior to enrichment in EE Broth, Mossel. The resuscitation procedure is recommended for dried foods (4), animal feeds (5) and semi-preserved foods (6). EE Broth, Mossel is an enrichment broth and should be used in conjunction with Violet Red Bile Glucose Agar (M581). Subcultures must be made onto lactose differential media as MacConkey Agar (M081), Deoxycholate Citrate Agar (M065) or Brilliant Green Agar (M016) for the detection of lactose negative or delayed lactose fermenters.

Type of specimen

Food samples

Specimen Collection and Handling

For food samples, follow appropriate techniques for sample collection and processing as per guidelines (7). 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. Avoid overheating of the medium as media is heat sensitive.

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 coloured homogeneous free flowing powder

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

Reaction: Reaction of 4.5% w/v aqueous solution at 25°C. pH : 7.2±0.2

pH: 7.00-7.40

Cultural Response

Cultural characteristics observed after an incubation at 35-37°C for 18-24 hours.

Key : (*) Corresponding WDCM numbers. (#) Formerly known as Enterobacter aerogenes

Storage and Shelf Life

Store between 10-30°C in a tightly closed container and the prepared medium at 15-25°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 (1,2).

Reference

1. Isenberg, H.D. Clinical Microbiology Procedures Handbook 2nd Edition.
2. 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. 1.
3. Mossel D.A.A., Visser M. and Cornellisen A.M.R., 1963,J.Appl.Bact.,26(3):444.
4. Mossel D.A.A. and Ratto M.A., 1970, Appl. Microbiol., 20:273.
5. Mossel D.A.A. and Shennan J.L. and Clare V., 1973, J. Sci. Fd Agric.,24:499.
6. Mossel D.A.A., Ratto M.A., 1973, J. Fd. Technol., 8:97.
7. Salfinger Y., and Tortorello M.L., 2015, Compendium of Methods for the Microbiological Examination of Foods, 5th Ed., American Public Health Association, Washington, D.C.
8. Van Schothurst M., et al, 1966, Vet Med., 13(3):273.