CRITERION™ RAPPAPORT-VASSILIADIS (MSRV)
MEDIUM BASE

Cat. no. C6740 CRITERION™ Rappaport-Vassiliadis (MSRV) Medium Base 63.2gm
Cat. no. C6741 CRITERION™ Rappaport-Vassiliadis (MSRV) Medium Base 500gm
Cat. no. C6742 CRITERION™ Rappaport-Vassiliadis (MSRV) Medium Base 2kg
Cat. no. C6743 CRITERION™ Rappaport-Vassiliadis (MSRV) Medium Base 10kg
Cat. no. C6744 CRITERION™ Rappaport-Vassiliadis (MSRV) Medium Base 50kg

INTENDED USE

Hardy Diagnostics CRITERION™ Rappaport-Vassiliadis (MSRV) Medium Base, with added novobiocin, is used in the detection and isolation of motile Salmonella spp. in feces and food products.

This dehydrated culture medium is a raw material intended to be used in the making of prepared media products, which will require further processing, additional ingredients, or supplements.

SUMMARY

Rappaport-Vassiliadis (MSRV) Medium, a modification of Rappaport-Vassiliadis Enrichment Broth, is used for detecting motile Salmonella in feces and food products following pre-enrichment or selective enrichment.(1) This semi-solid medium allows motility to be detected as halos of growth around the original inoculation point. MSRV Medium may be used as a plating medium for isolating Salmonella spp. (other than S. typhi and S. paratyphi type A) from stool specimens with high sensitivity and specificity.(17,18)

This medium is recommended by the European Chocolate Manufacturer's Association. A collaborative study conducted with the support of the American Cocoa Research Institute (ACRI) and the Canadian Chocolate Manufacturer's Association (CCMA) resulted in first action adoption of the MSRV method by AOAC International.(16)

Tryptose and casein hydrolysate are used as carbon and nitrogen sources. A high concentration of magnesium chloride was included to inhibit growth of Proteus and Escherichia coli. Novobiocin and malachite green inhibit organisms other than Salmonella. The combination of the low pH of the medium with novobiocin, malachite green, and magnesium chloride select for highly resistant Salmonella spp.

FORMULA

Gram weight per liter: 31.6gm/L
Magnesium Chloride 10.93gm
Sodium Chloride 7.34gm
Casein Acid Hydrolysate 4.59gm
Tryptose 4.59gm
Monopotassium Phosphate 1.47gm
Malachite Green 37.0mg
Agar 2.7gm

Final pH 5.2 +/- 0.2 at 25ºC.

* Adjusted and/or supplemented as required to meet performance criteria.

STORAGE AND SHELF LIFE

Store the sealed bottle(s) containing dehydrated culture medium at 2-30ºC. Dehydrated culture medium is very hygroscopic. Keep lid tightly sealed. Protect dehydrated culture media from moisture and light. The dehydrated culture media should be discarded if it is not free-flowing or if the color has changed from its original light blue.

Store the prepared culture media at 2-30ºC.

PRECAUTIONS

METHOD OF PREPARATION FOR DEHYDRATED CULTURE MEDIA

1. Suspend 31.6gm of the dehydrated culture media in 1 liter of distilled or deionized water.

2. Heat to boiling and mix to dissolve completely.

3. Do not autoclave.

4. Cool base medium to 45-50ºC.

5. Aseptically add 1ml of a 2% (20mg/L) filter sterilized solution of novobiocin.

6. Mix well and dispense as desired.

PROCEDURE AND INTERPRETATION OF RESULTS

For information on procedures and interpretation of results, consult listed references.

LIMITATIONS

The combination of malachite green, magnesium chloride and a low pH may inhibit certain Salmonella, such as S. typhi and S. cholerasuis.

Salmonella gallinarum is non-motile and does not produce a zone of turbidity.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as autoclaves, incinerators, incubators, and novobiocin solution, etc., are not provided.

QUALITY CONTROL

Test Organisms Inoculation Method* Incubation Results
Time Temperature Atmosphere
Salmonella enterica
ATCC ® 14028
** 18-24hr 35°C Aerobic Growth; positive motility indicated by a halo of >20mm
Citrobacter freundii
ATCC ® 8090
** 18-24hr 35°C Aerobic Partial to complete inhibition; negative motility
Pseudomonas aeruginosa
ATCC ® 27853
** 18-24hr 35°C Aerobic Inhibited

User Quality Control

** Refer to the Procedure section above.

PHYSICAL APPEARANCE

CRITERION™ Rappaport-Vassiliadis (MSRV) Medium Base powder should appear homogeneous, free-flowing, and light blue in color. The prepared media should appear slightly opalescent, and blue in color.

REFERENCES

1. Rappaport, F., et al. 1956. J. Clin. Path.; 9:261-266.

2. Vassiliadis, P., et al. 1978. J. Appl. Bact.; 44:233-239.

3. Jorgensen., et al. Manual of Clinical Microbiology, American Society for Microbiology, Washington, D.C.

4. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.

5. Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.

6. Koneman, E.W., et al. Color Atlas and Textbook of Diagnostic Microbiology, J.B. Lippincott Company, Philadelphia, PA.

7. MacFaddin, J.F. 1985. Media for Isolation, Cultivation, Identification, Maintenance of Bacteria, Vol. I. Williams & Wilkins, Baltimore, MD.

8. FDA. 1995. Bacteriological Analytical Manual, 8th ed. FDA.

9. Marshall, R.T., ed. 1992. Standard Methods for the Examination of Dairy Products, 16th ed. APHA, Washington, D.C.

10. Vanderzant, C. and D.F. Splittstoesser, (ed.). 1992. Compendium of Methods for the Microbiological Examination of Foods, 3rd ed. APHA, Washington, D.C.

11. Greenberg, A.E., et al. (ed.). 1992. Standard Methods for the Examination of Water and Wastewater, 18th ed. APHA, Washington, D.C.

12. U.S. Pharmacopeia, 22nd rev. 1990. U.S. Pharmacopeial Convention, Rockville, MD.

13. Quality Assurance for Commercially Prepared Microbiological Culture Media, M22. Clinical and Laboratory Standards Institute (CLSI - formerly NCCLS), Wayne, PA.

14. DeSmedt, J.M., et al. 1986. Rapid Salmonella detection in foods by motility enrichment on a modified semi-solid Rappaport-Vassiliadis Medium. J. Food. Prot.; 49:510-514.

15. DeSmedt, J.M., et al. 1987. Dynamics of Salmonella isolation with modified semi-solid Rappaport-Vassiliadis Medium. J. Food Prot.; 50:658-661.

16. DeSmedt, J.M., et al. 1994. Salmonella detection in cocoa and chocolate by motility enrichment on modified semi-solid Rappaport-Vassiliadis Medium: a collaborative study. J. AOAC Int.; 77:365-373.

17. Dusch, H., et al. 1995. Evaluation of five new plating media for isolation of Salmonella spp. J. Clin. Micro.; 33.802-804.

18. Aspinall, S.T., et al. 1992. Improved isolation of Salmonella from feces using a semi-solid Rappaport-Vassiliadis Medium. Eur. J. Clin. Microbiol. Infect. Dis.; 11:936-939.

19. Andrews, W.H., et al. 1995. Salmonella. p. 5.01-5.20. FDA Bacteriological Analytical Manual, 8th ed. AOAC International, Gaithersburg, MD.


ATCC is a registered trademark of the American Type Culture Collection.

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