ISO 21528-1:2017

ISO 21528-1:2017 specifies a method, with enrichment, for the detection of Enterobacteriaceae. It is applicable to
-      products intended for human consumption and the feeding of animals, and
-      environmental samples in the area of primary production, food production and food handling.
This method is applicable
-      when the microorganisms sought are expected to need resuscitation by enrichment, and
-      when the number sought is expected to be below 100 per millilitre or per gram of test sample.
A limitation on the applicability of ISO 21528-1:2017 is imposed by the susceptibility of the method to a large degree of variability (see Clause 11).
NOTE       Enumeration can be carried out by calculation of the most probable number (MPN) after incubation in liquid medium. See Annex A.