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AOAC Official Method 2014.xxx
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Enumeration of Yeast and Mold
in Food
2
3M
™
Petrifilm
™
Rapid Yeast and Mold Count Plate
3
First Action 2014
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(Applicable to the enumeration of yeast and mold in the following high water activity matrices:
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yogurt, frozen bread dough, fermented salami, sour cream, ready-made pie, raw frozen ground
7
beef patties (77% lean), ready-to-eat deli sandwiches, sliced apples, and the following low water
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activity matrices: raw almonds and dehydrated soup)
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See Tables
2014.1
and
2014.2
for a summary of results of the collaborative study.
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See Tables 2-9 for detailed of results of the collaborative study
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A. Principle
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The 3M Petrifilm Rapid Yeast and Mold Count (RYM) Plate is a sample-ready culture medium
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system which contains nutrients supplemented with antibiotics, a cold-water-soluble gelling
18
agent, and an indicator system that facilitates yeast and mold enumeration. 3M Petrifilm RYM
19
Count Plates are used for the enumeration of yeast and mold in as little as
20
48 hours in the food and beverage industries 3M
™
Food Safety is certified to ISO (International
21
Organization for Standardization) 9001 for design and manufacturing.
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B. Apparatus and Reagents
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B. (a)
3M
™
Petrifilm
™
Rapid Yeast and Mold Count Plate
– 25 plates/pouch
25
2 pouches /box. Available from 3M Food Safety (St. Paul, MN 55144-1000, USA).
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B. (b)
Sterile Diluent-
0.1% peptone water
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B. (c)
Pipettes-
capable of pipetting 1,000 µL or a serological pipette
28
B. (d)
Sterile pipette tips-
capable of 1,000 µL
29
B. (e)
Stomacher-
Seward or equivalent
30
B. (f)
Filter Stomacher bags
- Seward or equivalent
31
B. (g)
3M
™
Petrifilm
™
Flat Spreader
32
B. (h)
Incubators –
Capable of maintaining 25 ± 1̊C and 28 ± 1̊C and having a solid
33
front to maintain a dark interior
34
B. (i)
Refrigerator -
capable of maintaining 2-8̊ C, for storing the 3M Petrifilm RYM
35
plates
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B. (j)
L shaped spreaders
37
B. (k)
Standard Colony Counter or Illuminated Magnifier
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C. General Instructions
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C.
(a)
Store the 3M Petrifilm RYM Plates at 2-8°C. After opening the 3M Petrifilm RYM Plate
41
pouches, seal the pouch and store at ambient temperature, less than 60% relative humidity. Post
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incubation 3M Petrifilm RYM Plates can be stored at -10
o
C to -20
o
C for up to 3 days. Place the
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3M Petrifilm Flat Spreader on the center of the plate. Prior to use, place the plates on a flat
44
surface for 1 hour at room temperature (20-25
o
C/< 60%RH) and protected from light to allow the
45
gel to form. Hydrated plates can be stored at room temperature for up to 8 hours before use.
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C. (b)
Follow all instructions carefully. Failure to do so may lead to inaccurate results
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C.
(c) Safety Precautions
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Candidates for 2016 Method of the Year
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