Paragraph 5 Technique of tests

The sample shall be mixed thoroughly by shaking and the container opened with aseptic precautions. For the colony plate count the dilutions specified in sub-paragraphs (2) to (5) below shall be used. For each sample being tested not less than two plates shall be prepared. The Petri plates shall be incubated as specified in sub-paragraphs (2) to (5) below.

Any sample of raw milk, bulk milk heat treated for transportation or “Pasteurised” milk taken at the heat treatment establishment and intended for immediate testing. For raw milk and milk which has been heat treated elsewhere, 1 ml. of 1 in 1,000 dilution shall be plated. For milk pasteurised on the premises, 1 ml. of 1 in 100 dilution shall be plated. All plates shall be incubated at 30degC. +/-0.5degC. for 72 hours.

Any sample of “Pasteurised” milk taken at the heat treatment establishment and intended for incubation before testing. 1 ml. of 1 in 1,000 dilution shall be plated and the plates incubated at 21degC. +/-0.5degC. for 25 hours.

Any sample of “Sterilised” or “Ultra Heat Treated” milk taken at the heat treatment establishment. 1 ml., undiluted, shall be plated and the plates incubated at 30degC. +/-0.5degC. for 48 hours.

Any sample of “Ultra Heat Treated” milk taken after it leaves the heat treatment establishment and before delivery to the consumer. 1 ml. of 1 in 10 dilution shall be plated and the plates incubated at 30degC. +/-0.5degC. for 48 hours.