BS ISO 21528-1:2004

Microbiology of food and animal feeding stuffs. Horizontal methods for the detection and enumeration of Enterobacteriaceae. Detection and enumeration by MPN technique with pre-enrichment | Status: Superseded, Withdrawn

1 Scope This part of ISO 21528 specifies a method, with pre-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 food production and food handling.

Enumeration is carried out by calculation of the most probable number (MPN) after incubation at 37 °C (or 30 °C)1) in liquid medium. This method is applicable

• — when the microorganisms sought are expected to need resuscitation before enrichment, and
• — when the number sought is expected to be in the range 1 to 100 per millilitre or per gram of test sample.

A limitation on the applicability of this part of ISO 21528 is imposed by the susceptibility of the method to a large degree of variability (see Clause 11).