Description
The described method is a method for the enumeration of thermotolerant coliform bacteria in foods and feeds. After closer identification of thermotolerant coliform bacteria, the method is also applicable to the detection of Escherichia coli in foods and feeds. The method is applicable to all types of foods and feed. The method is especially suitable for the detection of stressed or sublethally injured bacteria. The number of thermotolerant coliform bacteria is determined by plating known quantities of a sample onto a non-selective agar medium. After preincubation at 20-25 °C (room temperature) for 1-2 hours, a selective medium containing lactose is poured on top of the agar. The plates are incubated at 44 °C for 24 hours, after which colonies with a typical or suspicious morphology are counted. Selected colonies are confirmed on suitable diagnostic media.