This part of ISO 11866|IDF 170 specifies a method for the enumeration of presumptive Escherichia coli by means of a colony-count technique at 44 °C. The method is applicable to -- milk, liquid milk products, -- dried milk, dried sweet whey, dried buttermilk, lactose, -- acid casein, lactic casein and rennet casein, -- caseinate and dried acid whey, -- cheese and processed cheese, -- butter, -- frozen milk products (including edible ices), and -- custard, desserts and cream. The method specified in this part of ISO 11866|IDF 170 is the preferred method for samples in which comparatively large numbers of presumptive Escherichia coli (more than 100 per gram or 10 per millilitre) are suspected.