This Standard sets out procedures for the examination of foods for coliforms and Escherichia coli by the triplicate tube method. This is a qualitative test and is suitable for determining the presence or absence of coliforms and E. coli in a stated quantity of material under test.

NOTES:

1.A flow diagram of the procedures is shown in Appendix A.

2 The method describes a general method and modifications may be required according to the material under test. Such modifications, if required, are prescribed in the method dealing with particular products.

3 Where the test is to estimate the level of coliforms only as an index of potential spoilage of the product and of hygiene, an incubation temperature of 30°C is specified. However, where the test is to be extended to include the estimation or detection of E. coli, incubation at 37°C is specified. Cultures which have been incubated initially at 30°C cannot be used for further tests for E. coli.

4 Methods for the examination of rinse fluids and filterable liquid products for coliforms and E. coli by membrane filtration are given in AS 5013.

5 Quantitative coliform and E. coli methods are given in AS 5013.3 and AS 5013.15 respectively.