RAPPAPORT Salmonella Enrichment Broth

EMD Cat. No. 1.10236.0500
500 g


Medium proposed by RAPPAPORT et al. (1956, 1959) for the selective enrichment of Salmonella (with the exception of S. typhosa) from fecal specimens, foodstuffs and other materials.

This broth is superior to other enrichments used for Salmonella - the yields obtained are several 10-fold higher (TRICHOPOULOS et al. 1972, IVESON et al. 1964). Yields are further increased by adding tetrathionate and substituting metachrome yellow with malachite green (HOFER 1969). GOOSENS et al. (1984) reported high isolation rates for salmonellae, when using a semi-soldid culture medium based on RAPPAPORT Broth.






Mode of Action Preparation
Experimental Procedure and Evaluation Quality Control
Typical Composition (g/liter)


Mode of Action
 Malachite green and magnesium chloride largely inhibit the growth of the microorganisms normally found in the intestine, but do not affect the proliferation of most salmonellae. Only S. typhosa and Shigellae are usually inhibited by malachite green. This culture medium is thus not suitable for the enrichment of these pathogenic organisms.
Preparation
Suspend 54 g/liter, dispense into test tubes, autoclave gently
(20 min at 115 °C).
pH: 6.0 ± 0.2 at 25 °C.
The prepared broth is clear and dark-blue.
  If the reconstituted medium is stored for a long period (about 2-3 weeks) a precipitate may occur, but this does not affect any of its properties.
Experimental Procedure and Evaluation
 Suspend the stool specimens in sterile physiological saline, ratio of up to 1:1000, add 3-4 drops of the suspension to a tube containing 5 ml enrichment broth. If only small quantities of salmonellae are suspected to be present, larger aliquots of the sample (1-2 g) should be added to 100 ml portions of the broth.
 Incubation: 18-24 hours  at 35 °C.
Streak samples from the resulting cultures onto selective culture media.
Quality control


Incolum
 		Growth after


24 hours
Escherichia coli ATCC 25922
 		approx. 99 %
 		10 %
Salmonella typhimurium ATCC 14028
 		approx.   1 %
 		90 %

Typical Composition (g/liter)
 Peptone from casein 5.0; sodium chloride 8.0; di-potassium hydrogen phosphate 0.8; magnesium chloride hexahydrate 40.0; malachite green 0.12.



© 2002 Merck KGaA, Darmstadt, Germany