IS 16067 : Part 1 : 2020/ISO 16649-1 : 2018 Microbiology of the Food Chain-Horizontal Method for the Enumeration of Beta-Glucuronidase-Positive Escherichia coli - Part 1 Colony-Count Technique at 44°C Using Membranes and 5-Bromo-4-Chloro-3-Indolyl Beta-D-Glucuronide

Revised Standard from Last Update.

NATIONAL FOREWORD

This Indian Standard (Part 1) (First Revision) which is identical with ISO 16649-1 : 2018 ‘Microbiology of the food chain — Horizontal method for the enumeration of beta-glucuronidase- positive Escherichia coli — Part 1: Colony-count technique at 44 °C using membranes and 5-bromo-4-chloro-3-indolyl beta-D-glucuronide’ issued by the International Organization for Standardization (ISO) was adopted by the Bureau of Indian Standards on recommendation of the Food Hygiene, Safety Management and Other Systems Sectional Committee and approval of the Food and Agriculture Division Council.

This standard was originally published in 2013 which was identical with ISO 16649-1 : 2001 under dual numbering The first revision of this standard has been undertaken to align it with the latest version of ISO 16649-1 : 2018.

The major changes in this revision are as follows:

a) samples from the environment and the primary production stage have been added to the scope;

b) the minimum length of incubation (20 h) for tryptone-bile X-glucuronide agar (TBX) during culture on selective medium has been adopted;

c) performance testing for the quality assurance of the culture media and the membrane for transfer has been added;

d) to improve safety for the user, the solvent dimethyl sulphoxide (DMSO) is no longer recommended to dissolve the chromogenic substrate (BCIG); and

e) the composition of the minerals-modified glutamate agar (MMGA) has been corrected (aspartic acid 0.024 g and arginine 0.02 g) to the values in the original formulation.

This Indian Standard is published in three parts. The other parts in this series are;

Part 2 Colony-count technique at 44°C using 5-bromo-4-chloro-3-indolyl β-D-glucuronide

Part 3 Detection and most probable number technique using 5-bromo-4-chloro-3-indolyl β-D-glucuronide

Only Part 1 of this standard has been adopted as an Indian Standard whereas other parts are under consideration.

The text of ISO Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain terminologies and conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following:

a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’.

b) Comma (,) has been used as a decimal marker, while in Indian Standards, the current practice is to use a point (.) as the decimal marker.