Microsoft Word - 3M Petrifilm REC Plate OMA Manuscript 09121

ERP Methods Book

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A total of 30 closely related non‐ E. coli  species and 30 isolates of non‐coliform species were  1

cultured in Brain heart infusion broth at 37 ± 2°C for 20–24 h.    2

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Isolates from the following sources were used in the study: American Type Culture 

Collection (ATCC), Manassas, VA; Q Laboratories Culture Collection (QL), Cincinnati, OH; NITE  4

Biological Resource Center (NBRC), Tokyo, Japan; National Collection of Type Cultures,  5

Salisbury, UK; and 3M Food Safety Center, St. Paul, MN. Inclusivity and exclusivity cultures each  6

were serially diluted in BPBD, randomized, blind‐coded and then plated in triplicate onto 3M  7

Petrifilm Rapid E. coli /Coliform Count Plates. For each isolate, a plate was incubated at 32 ± 1°C,  8

35 ± 1°C, and 42 ± 1°C for 18–24 h. Isolates were also plated onto Violet Red Bile (VRB) with  9

VRB plus 4‐methyl‐umbelliferyl‐β‐D‐glucuronide (MUG) overlay for comparison to BAM Ch. 4  10

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and incubated at the same temperatures for 18–24 h. 

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In addition, inclusivity and exclusivity cultures each were serially diluted in PSS, randomized, 

blind‐coded and then plated in triplicate onto 3M Petrifilm Rapid E. coli /Coliform Count Plates.  13

For each isolate, a plate was incubated at 30 ± 1°C, 37 ± 1°C and 42 ± 1°C for 18–24 h. The  14

coliform inclusivity and exclusivity isolates were also plated onto VRBL agar for comparison to  15

ISO 4832:2006. Plates were incubated at the same temperatures for 24 ± 2 h. The E. coli 16

inclusivity and exclusivity isolates were also plated onto Tryptone Bile X‐glucuronide medium  17

(TBX) for comparison to ISO 16649‐2:2001. Plates were incubated at 30 ± 1°C, 37 ± 1°C and 44 ±  18

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1°C for 18–24 h. 

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Inclusivity/Exclusivity Testing Results 

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December 6, 2018