AS 4276.21-2005

Water microbiology Examination for coliforms and Escherichia coli - Determination of most probable number (MPN) using enzyme hydrolysable substrates

Standards Australia

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1 - AS 4276.21-2005 WATER MICROBIOLOGY - EXAMINATION FOR COLIFORMS AND ESCHERICHIA COLI-DETERMINATION OF MOST PROBABLE...
1 - PREFACE
1 - FOREWORD
2 - METHOD
2 - 1 SCOPE
2 - 2 REFERENCED DOCUMENTS
2 - 3 DEFINITIONS AND ABBREVIATIONS
2 - 3.1 Definitions
2 - 3.1.1 Coliforms
2 - 3.1.2 Escherichia coli
2 - 3.2 Abbreviations
2 - 4 PRINCIPLE
3 - 5 CULTURE MEDIA AND REAGENTS (see Appendix B)
3 - 5.1 Culture media
3 - 5.1.1 EHS medium with ONPG and MUG
3 - 5.2 Reagents
3 - 5.2.1 Buffered peptone water
3 - 5.2.2 Peptone solution, 0.1 percent
3 - 5.2.3 Ringer™s solution, quarter strength
3 - 6 APPARATUS
3 - 6.1 Multiple tube dilution technique (MPN) (Refer to AS 4276.4)
3 - 6.1.1 Rimless bacteriological test tubes or equivalent of appropriate size.
3 - 6.1.2 Containers
3 - 6.1.3 Pipettes or equivalent measuring devices
3 - 6.2 Multiple well technique
3 - 6.2.1 Pre-sterilized 100 mL containers
3 - 6.2.2 Pre-sterilized multiple well trays
3 - 6.2.3 Multiple well tray sealer
3 - 6.3 Common apparatus
3 - 6.3.1 Incubators or water baths
3 - 6.3.2 Colour/fluorescence comparators
3 - 6.3.3 Ultra violet viewing cabinet
3 - 7 REFERENCE CULTURES
3 - 7.1 Positive cultures
3 - 7.1.1 Enterobacter aerogenes
4 - 7.1.2 Escherichia coli
4 - 7.2 Negative cultures
4 - 7.2.1 Aeromonas hydrophila
4 - 7.3 Use of reference cultures
4 - 8 SAMPLES
4 - 8.1 Laboratory samples
4 - 8.2 Dilutions
4 - 9 PROCEDURE
4 - 9.1 Multiple tube dilution technique (Refer to AS 4276.1)
5 - 9.2 Multiple well technique
5 - 10 INTERPRETATION OF THE TESTS
6 - 11 DETERMINATION OF MOST PROBABLE NUMBER (MPN) OF COLIFORMS AND E. coli
6 - 12 TEST REPORT
7 - APPENDIX A - FLOW CHART FOR COLIFORMS AND E. coli BY THE ENZYME HYDROLYSABLE SUBSTRATE (EHS) METHOD
8 - APPENDIX B - CULTURE MEDIA AND REAGENTS
8 - B1 SCOPE
8 - ¿B2 ENZYME HYDROLYSABLE SUBSTRATE WITH O-NITROPHENYL-(-D-GALACTOPYRANOSIDE ¿ONPG) AND 4ŒMETHYLUMBELLIFERYL-¿-D...
8 - B3 BUFFERED PEPTONE WATER
9 - B4 PEPTONE SOLUTION, 0.1 PERCENT
9 - B5 RINGER™S SOLUTION, FULL STRENGTH
10 - APPENDIX C - PREPARATION OF A COMPARATOR
10 - C1 INTRODUCTION
10 - C2 PROCEDURE

Abstract

Sets out the method for simultaneously detecting coliforms
and E. coli in water using enzyme hydrolysable substrates
using the multiple tube dilution or multiple well technique.

Scope

This Standard sets out the method for simultaneously detecting coliforms and E. coli in water using enzyme hydrolysable substrates using the multiple tube dilution or multiple well technique.

Water other than fresh water (estuarine or brackish water) may contain ONPG positive non-target microorganisms (e.g. Vibrio species) that may produce false positive results. Use of this method with these matrices would need to be validated.
A flow diagram of the procedure is shown in Appendix A.