AS/NZS 1766.2.15:1998

AS/NZS 1766.2.15:1998 FOOD MICROBIOLOGY - EXAMINATION FOR SPECIFIC ORGANISMS-LISTERIA MONOCYTOGENES IN DAIRY PRODUCTS

PREFACE

CONTENTS

1 Scope

2 Normative references

3 Definitions

3.1 Listeria spp.:

3.2 detection of Listeria monocytogenes:

4 Principle

4.1 Enrichment in selective liquid medium

4.2 Isolation and presumptive identification

4.3 Confirmation

5 Culture media and reagent

5.1 General

5.2 Culture media

5.2.1 Selective medium: Enrichment medium

5.2.2 Isolation medium (Oxford agar)

5.2.3 Solid cul ture medium: Tryptone soya yeast extract agar (TSYEA)

5.2.4 Liquid culture medium: Tryptone soya yeast extract broth (TSYEB)

5.2.5 Blood agar

5.2.6 Carbohydrate utilization broth

5.2.7 Motility medium

5.2.8 CAMP (Christie, Atkins, Munch-Petersen) test

5.3 Reagent

6 Apparatus and glassware

6.1 Apparatus

6.1.1 Apparatus for dry sterilization (oven) or wet sterilization (autoclave) (see ISO 7218)

6.1.2 Incubator,

6.1.3 Incubator,

6.1.4 Incubator,

6.1.5 Waterbaths,

6.1.6 Blending equipment

6.1.7 Loops,

6.1.8 Inoculating needle,

6.1.9 Temperature-compensated pH-meter

6.1.10 Refrigerator

6.1.11 Source of beamed whi te light

6.1.12 Mirror,

6.1.13 Tripod,

6.1.14 Phase-contrast microscope,

6.2 Glassware

6.2.1 Culture flasks,

6.2.2 Culture tubes

6.2.3 Measuring cylinders,

6.2.4 Graduated pipettes,

6.2.5 Sterile Petri dishes

6.2.6 Microscopic slides

6.2.7 Glass beads

7 Sampling

8 Preparation of test sample

8.1 Milk

8.2 Dried milk, dried whey, dried buttermilk, lactose, case in and caseinate

8.3 Butter

8.4 Cheese

8.5 Edible ices

8.6 Fermented milks, yoghurts, custards and desserts

9 Procedure

9.1 Inoculation of enrichment medium

9.1.1 Milk

9.1.2 Dried milk, dried whey, dried buttermilk and caseinate

9.1.3 Casein

9.1.4 Butter

9.1.5 Cheese

9.1.6 Frozen milk products (including edible ices)

9.1.7 Fermented milks, yoghurts, custards and desserts

9.2 Incubation

9.3 Isolation and presumptive identification

9.4 Confirmation

9.4.1 Selection of colonies for confirmation

9.4.2 Incubation

9.4.3 Catalase reaction

9.4.4 Morphology and staining properties

9.4.5 Haemol ysis

9.4.6 Further biochemical confirmation

9.5 Interpretation of morphological and physiological properties and of biochemical reaction (see table 1)

9.6 Definitive confirmation

9.7 Control cultures

10 Expression of results

11 Test report

Annex A - SAFETY PRECAUTIONS

Annex B - BIBLIOGRAPHY

TECHNICAL CORRIGENDUM 1

ANNEX ZZ - VARIATIONS TO ISO 10560:1993 FOR AUSTRALIAN/NEW ZEALAND CONDITIONS

ZZ1 SCOPE

ZZ2 VARIATIONS