ABSTRACT
The members of the Enterobacteriaceae family are Gram-negative bacteria in the shape of straight rods, non-spore forming, facultative anaerobic and oxidase negative. Enterobacteriaceae are chemoorganotrophs with both a respiratory and fermentative metabolism. Enterobacteriaceae are widely distributed throughout nature and are found in the soil, water, plants, fruits, vegetables, meats, eggs, grains, animals, insects and in man. Several Enterobacteriaceae are also pathogenic for man, posing a serious hazard to public health. The quantification of Enterobacteriaceae can be achieved by the standard plate count method using violet red bile glucose (VRBG) agar as the culture medium. VRBG is a differential selective medium containing crystal violet and bile salts, which inhibit Gram-positive bacteria. The enumeration of Enterobacteriaceae by the most probably number or presence/absence method is indicated when the microorganisms are expected to need resuscitation by enrichment or when low counts are expected.
