BS ISO 6730:2005,Milk — Enumeration of colony-forming units of psychrotrophic microorganisms — Colony-count technique at 6,5 degrees C.
ISO 6730|IDF 101:2005 specifies a method for the enumeration of colony-forming units of psychrotrophic microorganisms in raw and heat-treated milk by means of the colony-count technique at 6,5 degrees Celsius.
2 Normative references
ISO 7218: 1996, Mcroboogy of food and anima feeding stuffs-General rules for microbiological examinations;
4 Principle
4.1 Poured plates are prepared using a specified culture medium and a specified quantity of the test sample. Other plates are prepared under the same conditions, using decimal dilutions of the test sample.
4.2 The plates are aerobically incubated at 6,5 C for 10 days.
4.3 The number of colony-forming units(CFU)of microorganisms per millilitre of sample is calculated from the number of colonies obtained on plates chosen at dilution levels so as to give a significant result.