Eijkman Test Principle and Procedure

 The IMViC test has two drawbacks. The first, It has many controversial procedures and second is test results do not give satisfactory differentiation between fecal and non-fecal coliforms. In 1904 Eijkman proposed another test to differentiate fecal and non-fecal coliform.

Principle of Eijkman Test

• Only fecal coliforms of warm blooded animals grow at 46°C and ferment lactose with Acid & Gas production
• Most strains of fecal E.coli can ferment lactose in a special buffered broth when incubated at 45°C, where as very few or less frequently the Enterobacter aerogenes do so.
• The test is called as Eijkman test or elevated temperature test.

Procedure of Eijkman Test

• A buffered tryptose lactose broth in tubes with inverted Durham's tube is inoculated with a culture of coliforms.
• It is then incubated in water jacketed incubator at 45°C for 48 hours.
• Gas production after incubation constitutes a positive test for fecal coliforms.
• Another method, instead of tryptone lactose broth, buffered boric acid lactose broth (BALB) medium is used.
• The advantage is that, the medium used is selective for fecal Escherichia.
• It selectively inhibits growth and gas production by Enterobacter and other intermediate members of coliforms.
• Sterile medium is first warmed to 37°C and then inoculated with culture & incubated at 45°C for 48 hrs.
• Gas production indicates positive test.
• Eijkman test gives better result than IMViC tests.
• Therefore, it is generally preferred in water examination.