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Material Safety Data Sheet


Organisms this product works with:

Dehydrated Culture Media


Code: CM1115

an enrichment medium for bile-tolerant Gram-negative bacteria in the microbiological examination of pharmaceutical products

Typical Formula


Pancreatic digest of gelatine


Glucose anhydrous


Bile Salts (Sodium desoxycholate, Sodium lauryl sulphate, Sodium citrate)


Potassium dihydrogen phosphate


Disodium hydrogen phosphate anhydrous


Brilliant green


 pH 7.2 ± 0.2 @ 25°C 
†      4.5g of Glucose anhydrous are equivalent to 5.0g of Glucose monohydrate
††    3.055g of bile salts are equivalent to 20.0g of dehydrated ox bile
†††  6.4g of Disodium hydrogen phosphate anhydrous are equivalent to 8.0g of Disodium hydrogen phosphate dihydrate.

Dissolve 25.97g in 1 litre of purified water. Mix well and distribute 100ml into 250ml flasks. Heat the medium at 100°C using free flowing steam for 30 minutes only.  Cool rapidly in cold running water.  DO NOT AUTOCLAVE.

Enterobacteria Enrichment Broth-Mossel (EP/USP/JP/BP) is recommended as an enrichment medium for bile-tolerant Gram-negative bacteria in the microbiological examination of pharmaceutical products. It can be used as test for absence or quantitative test1.

Oxoid Enterobacteria Enrichment Broth-Mossel (EP/USP/JP/BP) was formulated to overcome the unsatisfactory effects of inhibition on small numbers of bile-tolerant gram negative cells due to bile salt variations. The inclusion of purified ox bile eliminated these problems and a preliminary assay can be used to check growth by inoculating approximately one viable cell per medium unit2,3.

Enterobacteria Enrichment Broth-Mossel (EP/USP/JP/BP) should be used as an enrichment broth in conjunction with Violet Red Bile Glucose Agar (R455302).

Additional information about this and other products in our harmonised range can be obtained by downloading our Harmonised Culture Media Portfolio.


  1. Sample preparation and pre-incubation
    Prepare a sample using a 1 in 10 dilution of not less than 1g of the product to be examined as described in general chapter EP 2.6.12 (Harmonised method), but using casein soya bean digest broth (CM0129) as the chosen diluent, mix and incubate 20-25°C for a time sufficient to resuscitate the bacteria but not sufficient to encourage multiplication of the organisms (usually 2 hours but not more than 5 hours).
  2. Test for absence
    Unless otherwise prescribed, use the volume corresponding to 1g of the product, as prepared in 1, to inoculate Enterobacteria Enrichment Broth-Mossel (CM1115). Incubate at 30-35°C for 24-48 hours. Subculture on plates of Violet Red Bile Glucose Agar (R455302). Incubate at 30-35°C for 18-24hours. The product complies with the test if there is no growth of colonies.
  3. Quantitative test
    1. Selection and subculture: inoculate suitable quantities of Enterobacteria Enrichment Broth Mossel (CM1115) with the preparation as described under 1 and/or dilution of it containing respectively 0.1g, 0.01g and 0.001g (or 0.1ml, 0.01ml and 0.001ml) of the product to be examined. Incubate at 30-35°C for 24-48 hours. Subculture each of the cultures on a plate of Violet Red Bile Glucose Agar (R455302). Incubate at 30-35°C for 18-24 hours.
    2. Interpretation: growth of colonies constitutes a positive result. Note the smallest quantity of the product that gives a positive result and the largest quantity that gives a negative result. Determine from the table below the probable number of bacteria.

      Results for each quantity of product 

      Probable number of bacteria per gram or millilitre of product

      0.1g or 0.1ml

      0.01g or 0.01ml

      0.001g or 0.001ml








      <103 and >10




      <102 and >101





Storage conditions and Shelf life

Store the dehydrated medium at 10-30°C and use before the expiry date on the label.
Store the prepared medium at 2-25°C.

Dehydrated medium: Pale green, free-flowing powder
Prepared medium: Green solution
Quality control
Inoculate the test strains individually. Use a number of micro-organisms equivalent to not more than 100 CFU in the inoculated test preparation.

Positive controls:Expected results
Escherichia coli ATCC® 8739Good growth
Pseudomonas aeruginosa ATCC® 9027 Good growth
Negative control: 
Staphylococcus aureus ATCC® 6538Inhibited

* This organism is available in Quanti-Cult™ format
As indicated by testing recovery levels on Violet Red Bile Glucose Agar (R455302)

1. European Pharmacopoeia 6.1.  2.6.13 Microbiological Examination of Non-Sterile Products: Test for Specified Micro-organisms. B. Harmonised Method.
2. Mossel D. A. A., Harrewijn G. A. and Nesselrooy-van Zadelhoff C. F. M. (1974) Health Lab. Sci. 11. 260-267.
3. Richard N. (1982) in Quality Assurance and quality control of microbiological culture media. Ed. J.E.L. Corry. G.I.T. - Verlag Darmstadt. pp 51-57.

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