Micro December 2018

AOAC Official Method 2018.XX 1 Enumeration of Escherichia coli and Coliform in a Broad Range of Foods and Select 2 Environmental Surfaces 3 3M Petrifilm Rapid E. coli/ Coliform Count Plate 4 First Action 2018 5 6 (Applicable to the enumeration of E. coli and coliform from pasteurized whole milk, butter, non- 7 fat dry milk, raw ground pork, lamb chop, raw ground chicken, chicken carcass rinsate, shell 8 eggs, liquid egg whites, powdered egg whites, sprouts, cranberries, infant formula with 9 probiotics, infant formula without probiotics, infant rice cereal without probiotics, dry dog 10 kibble, dry cat food, flour, chocolate chip cookie dough, raw ground beef (73% lean), raw frozen 11 chicken wings, raw milk, whole liquid egg, tuna sushi, smoked salmon, bunched spinach, 12 pasteurized carrot juice, ready-made sandwiches, raw vegetable salad with dressing, chicken 13 feed, soybean meal, stainless steel environmental sponges and sealed concrete environmental 14 sponges) 15 16 See Table 2018.1A-B for a summary of results of the collaborative study. 17 See Tables 1-4 for detailed results of the collaborative study 20 21 The 3M Petrifilm Rapid E. coli /Coliform Count Plate is a self-contained, sample-ready-culture- 22 medium system which contains a cold-water-soluble gelling agent and two different indicators; 23 5-bromo-4-chloro-3-indolyl-D-glucuronide that indicates glucuronidase activity and tetrazolium 24 that facilitates colony enumeration. The 3M Petrifilm Rapid E. coli /Coliform Count Plate is 25 intended for the use for the enumeration of both Escherichia coli and coliforms in various food 26 and beverage products and from environmental surfaces. The 3M Petrifilm Rapid E. 27 coli /Coliform Count Plates can be incubated for 18 - 24 hours at 30 o C, 32 o C, 35 o C, 37 o C, and 28 42 o C.The typical colony morphology for E. coli is blue to blue-green colonies with or without 29 gas production, regardless of size or color intensity. Other coliform isolates will appear as red 30 colonies with entrapped gas (within approximately one colony diameter) for enumeration 31 according to FDA BAM, and red colonies with and without gas production according to ISO 32 4832:2006. The accurate quantitative range is less than or equal to 100 CFU per plate for the 33 total coliform count, and less than or equal to 100 blue to blue-green CFU per plate for the E. 34 coli count. 18 19 A. Principle

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B. Apparatus and Reagents

a. 3M Petrifilm Rapid E. coli/Coliform Count Plates –. Available from 3M Food Safety

- CAT# 6436/6437.

b. 3M Petrifilm Spreader – CAT# 1223767436

c. Sterile Diluent- Peptone Salt Solution & Butterfield’s Phosphate Buffered Diluent d. Pipettes- capable of pipetting 1,000 µL or a serological pipette

e. Sterile pipette tips- capable of 1,000 µL f. Laboratory paddle-blender- Seward 400 or equivalent g. Filter Stomacher bags - Seward or equivalent

h. Incubators – Capable of maintaining 30 ± 1 o C, 32 ± 1 o C, 35 ± 1 o C, 37 ± 1 o C or 42 ±

1 o C

i. Refrigerator - capable of maintaining 0-8 o C, for storing plates

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