Explain about the IMViC Test?

IMViC test is a combination of four tests:

(1) Indole production

(2) Methyl Red test

(3) Voges Proskauer, and

(4) Citrate Utilization test

The name IMViC includes the first letter of each test and the lower case 'i' is included to facilitate pronunciation. The test is used to differentiate among different genera of the family Enterobacteriaceae particularly E. coli and Enterobacter. Enterobacteriaceae family include pathogens like Salmonella, Shigella; occasional pathogens like Proteus, Klebsiella and normal saprophytes, e.g., E. coli and Enterobacter. Identification of these organisms is essential to control the intestinal infections by preventing contamination of food and water by these organisms. Checking for each and every organism in food is, however, a tedious job.

So detection of indicator organisms in food and water may be used as indication of faecal contamination and possibility of the presence of pathogens in food and water. Coliforms are used as indicator organisms. Coli is a normal inhabitant of intestine while Enterobacter is present on plant surfaces. For better indication of faecal contamination, the two, i.e., E. coli and Enterobacter can be separated by performing IMViC test. The test can also be used to differentiate other members of Enterobacteriaceae and also other intestinal organisms on the basis of their enzymatic reactions in presence of specific substrates.