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Evaluation of the 3M
™
Petrifilm
™
Rapid Yeast and Mold Count
1
Plate
for the Enumeration of Yeast and Mold in Food:
2
Collaborative Study
3
4
Patrick Bird, Jonathan Flannery, Erin Crowley, James Agin, David Goins
5
Q Laboratories, Inc., 1400 Harrison Ave, Cincinnati, OH 45214
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Robert Jechorek
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3M Food Safety Department,
3MCenter – Bldg. 260-6B-01, St. Paul, MN 55144
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Collaborators: D. Metzger, W. Lee, T. Hirsch, P. Fatemi, S. Spencer, J. Blumfield, B. Dieckleman,
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K. Gonzales, C. Fagundes, J. Reed, J. Medellin, A. Hankins, R. Dermer, N. Shipley, J. Williams, A.
12
Morris, R. Brooks, K. Powers, B. Brown, K. Beers, A. Calle, J. Pickett, J. Reynolds, A. Gaydos, A.
13
Mastalerz
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The 3M
™
Petrifilm
™
Rapid Yeast and Mold (RYM) Count Plate
is a simple, ready to use
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chromogenic culture method for the rapid detection and enumeration of yeast and mold in
17
food products. The 3M Petrifilm RYM Count Plate was compared to the FDA BAM
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Chapter 18
Yeasts, Molds and Mycotoxins
and the ISO 21527:2008
Microbiology of food and
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animal feeding stuffs – Horizontal method for the enumeration for yeast and molds
– Part 1:
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Colony count technique in products with water activity greater than 0,95
and Part 2:
Colony
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count technique in products with water activity less than or equal to 0,95
reference methods
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for raw almonds and raw frozen ground beef patties (77% lean). The 3M Petrifilm RYM
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Count Plate was evaluated using a paired study design in a multi-laboratory collaborative
24
study following the current AOAC Validation Guidelines. Three (3) target contamination
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levels (low, 10-100 colony forming unit (CFU)/g; medium, 100-1,000 CFU/g; high 1,000-
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10,000 CFU/g) as well as an uninoculated control level (0 CFU/g) were evaluated for each
27
matrix. Samples evaluated by the 3M Petrifilm RYM Count Plate were prepared in
28
duplicate and incubated at both 25
o
C and 28
o
C. Plates at both temperatures were
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enumerated after 48 and 60 hours of incubation. No significant difference was observed
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between the 3M Petrifilm RYM Plate Count and the FDA BAM or ISO 21527 reference
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methods for each contamination level. No statistical differences were observed between
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samples analyzed by the 3M Petrifilm RYM Count Plate (at either 25
o
C or 28
o
C) and the
33
reference methods. No statistical significant differences were observed between
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enumeration of colonies at 48 and 60 hours on the 3M Petrifilm RYM Count Plate and the
35
reference methods.
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Foodborne yeasts and mold constitute a large and diverse group of microorganisms. Due to their
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heterotrophic nature, these microorganisms are able to adapt and survive in a wide range of
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environmental conditions including acidic and alkaline conditions, temperatures ranging from
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5
o
C to 35
o
C and in low moisture products (<0.85
Aw
) [1, 2]. Many of these species cause varying
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degrees of food decomposition leading to substantial economic loses [2]. Several foodborne
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molds, and possibly some yeasts, may also be hazardous to human health due to their ability to
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produce toxic metabolites [1]. The presence of these microorganisms in food commodities can
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indicate contamination of the product, inadequately cleaned food processing equipment or
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inadequate food storage facilities [2]. Cultural enumeration of yeasts and molds can take 5 to
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Candidates for 2016 Method of the Year
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