Organisms this product works with:
Other products used in the isolation of Salmonellae:
MODIFIED SEMI-SOLID RAPPAPORT VASSILIADIS AGAR (ISO)
Code: CM1112
Modified Semi-solid Rappaport-Vassiliadis (MSRV) Agar (ISO) is used for the selective enrichment of Salmonella spp. from food, animal faeces and environmental samples from the primary stage of animal production. This medium meets the specifications for formulation and performance described in ISO 6579:2002 +A1:2007Annex D1.
Typical Formula* | gm/ litre |
Enzymatic digest of animal and plant tissue | 4.6 |
Acid hydrolysate of casein | 4.6 |
Sodium chloride | 7.3 |
Potassium dihydrogenphosphate (KH2PO4) | 1.5 |
Magnesium chloride anhydrous (MgCl2) | 10.9 |
Malachite green oxalate | 0.04 |
Agar | 2.7 |
pH 5.2† (5.1 to 5.4) @ 25°C |
NOVOBIOCIN SUPPLEMENT
Code: SR0181
Vial Contents (each vial sufficient for 1 litre of medium) | per vial | per litre |
Novobiocin | 10mg | 10mg |
Directions
Suspend 31.6g of MSRV (ISO) Agar base in 1 litre of distilled water. Bring to the boil with frequent agitation. DO NOT AUTOCLAVE. Cool to 50°C, and aseptically add the contents of 1 vial of Novobiocin Supplement (SR0181), reconstituted as directed. Mix well, and pour into sterile Petri dishes. This medium is semi-solid, therefore do not invert plates.
Description
Modified Semi-solid Rappaport Vassiliadis Agar (ISO) is based on the formulation described by De Smedt et al., which has been shown to detect more Salmonella-positive samples than traditional enrichment procedures2,3. Further collaborative studies have confirmed these findings4,5.
Motility enrichment on MSRV Agar has been designed as a simple and sensitive method for the isolation of salmonellae from food and environmental samples. It has been incorporated into ISO 6579:2002 +A1:2007 Annex D1, which applies to the isolation of Salmonella spp. from animal faeces (such as poultry, pigs and cattle) and environmental samples associated with the primary stage of animal production (such as dust). In Annex D, MSRV Agar replaces Rappaport-Vassiliadis Broth, which is still used in ISO 6579:2002 +A1:2007 for the selective enrichment of Salmonella spp. in food.
The efficiency of the medium is based on the ability of salmonellae to migrate through the selective medium ahead of competing Gram-negative, motile organisms, thus producing opaque halos of growth. Novobiocin, low pH, high magnesium chloride concentration and malachite green inhibit the growth of Gram-positive flora.
Subculture should be carried out from the migrated culture, with the inoculum being taken from the furthest edge of the growth. Presumptive identification is achieved by subculture onto XLD Agar and a second Salmonella agar of choice. Characteristic presumptive Salmonella colonies should be confirmed according to directions in ISO 6579:2002 +A1:2007 Annex D1. Alternatively, Oxoid Salmonella Latex Test FT0203 or DR1108 may be used for serological confirmation of Salmonella spp. MSRV (ISO) Agar is not suitable for the detection of non-motile strains of Salmonella (clinical incidence <0.1%)6.
Technique
Refer to relevant standard method for detailed instructions. The following method is a summary of ISO 6579:2002 +A1:2007 Annex D1.
Storage conditions and Shelf life
MSRV (ISO) should be stored in the tightly capped original container at 10-30°C. Novobiocin Supplement should be stored in the dark at 2-8°C. When stored as directed, the un-opened products will remain stable until the expiry date printed on the packaging.
Locally prepared MSRV (ISO) plates can be stored for up to 2 weeks when made from CM1112 and SR0181 according to the manufacturer’s instructions and stored at 2-8°C, out of direct sunlight. A longer shelf life may be attainable, but should be validated under the relevant, local manufacturing and storage instructions.
Appearance
Dehydrated culture medium: Blue/green, free-flowing powder
Selective Supplement: White, freeze-dried pellet
Prepared medium: Blue, semi-solid gel
Quality control
Positive controls: | Expected results |
Salmonella Typhimurium ATCC®14028* | Straw colonies at site of inoculation surrounded by white/grey halo of growth |
Salmonella Enteritidis ATCC®13076* | Straw colonies at site of inoculation surrounded by white/grey halo of growth |
Negative controls: | |
Escherichia coli ATCC®8739* | Restricted or no growth |
Enterococcus faecalis ATCC®19433* | Restricted or no growth |
Precautions
MSRV (ISO) Agar is for laboratory use only. Do not use the dehydrated medium beyond the stated expiry date or if the product shows any sign of deterioration.
Basal medium is very hygroscopic.
When handling powder a face mask and gloves must be worn. Refer to material safety data sheet for details.
Refs
1. ISO 6579:2002 +A1:2007 Annex D.
2. De Smedt J. M., Bolderdijk R., Rappold H. and Lautenschlaeger D. (1986) J. Food. Prot. 49. 510-514.
3. De Smedt J. M., Bolderdijk R. (1987) J. Food. Prot. 50. 658-661.
4. De Zutter L. et al. (1991) Int. J. Food Micro. 13. 11-20.
5. De Smedt J. M. et al. (1991) Int. J. Food Micro. 13. 301-308.
6. Holbrook R., Anderson J. M., Baird-Parker A. C., Dodds L. M., Sawhney D., Struchbury S. H. and Swaine D. (1989) Lett. Appl. Microbiol. 8. 139- 142.
ATCC® is a registered trademark of American Type Culture Collection