Description
Quantity: 500 g
Unit Size: Each
Use MRVP Broth for differentiation of coli-aerogenes group by the Methyl-red and Voges-Proskauer test.Smith^2 noted the low acid production of Enterobacter aerogenes cultures as compared with those of Escherichia coli. Clark & Lubs^3 employed methyl-red as a hydrogen-ion concentration indicator in order to differentiate glucose phosphate peptone water cultures of members of the coli-typhoid group. This test, now known as the Methyl-red test, distinguishes those organisms able to form large amounts of acid from glucose so that the pH falls below 4.4 and those organisms which cannot produce a low pH level.The difference in pH value is visualised by adding methyl-red to the culture, (pH 6.0 yellow).Voges & Proskauer^4 described a red fluorescent coloration that appeared after the addition of potassium hydroxide to cultures of certain organisms in glucose medium. The coloration was shown to be due to the oxidation of the acetylmethyl-carbinol producing diacetyl which reacts with the peptone of the medium to give a red colour^5,6. Durham^7 noted that Enterobacter aerogenes gave a positive reaction but that Escherichia coli produced no coloration, and it later became clear that there was a negative correlation between the Methyl-red and Voges-Proskauer tests^8,9 for lactose-fermenting coliform organisms.Not all products are available for sale in all territories. Please inquire.Remel™ and Oxoid™ products are now part of the Thermo Scientific brand.
