Microsoft Word - 3M Petrifilm REC Plate OMA Manuscript 09121

ERP Methods Book

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1.1 mL sample volume, 16 h incubation time; and 4 ) 1.1 mL sample volume, 28 h incubation  1

time. The nominal test condition is 1.0 mL sample volume, 18–24 h incubation time. Inoculum  2

of Klebsiella oxytoca  (ATCC 51817) and E. coli  (ATCC 8739) were each prepared by transferring a  3

single bacterial colony from SBA into ISO‐BPW and incubating at 35 ± 1 o C overnight. Following  4

incubation, the cultures were homogenized and diluted to a targeted low‐level (10‐100  5

CFU/mL) and high‐level (1,000‐10,000 CFU/mL) using ISO‐BPW. Five individual test portions  6

were analyzed with each strain for each targeted inoculation level. In addition, five test  7

portions were inoculated with a non‐target isolate,  Staphylococcus aureus  (ATCC 6538). The  8

samples were plated onto 3M Petrifilm Rapid E. coli /Coliform Count Plate and incubated at 35 ±  9

1°C following each treatment combination plus the nominal test condition.  10 11 Robustness Testing Results   12

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For the robustness evaluation, there were no statistically significant differences using the 

difference of means between each test combination and the nominal combination for both  15

coliform and E. coli at both contamination levels. In addition, all test portions inoculated with  16

the non‐target strain for each treatment combination were not detected. Mean differences and  17

95% confidence intervals for each combination, target analyte and inoculation level are  18

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presented in Table 16.  

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Stability (Lot‐to‐Lot) Study 

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December 6, 2018