AOAC-RI ERP Book Micro Jan 19 2017

presented here were statistically analyzed according to the POD methods of the 2012 version of the AOAC International Methods Committee Guidelines for Validation of Microbiological Methods for Food and Environmental Surfaces document (1). The POD CP , POD CC , dPOD CP , POD C , POD R , and dPOD C values calculated at each level of inoculation for the candidate method and the reference method testing of sprouts, and their corresponding 95% confidence intervals, are provided below in Table 9.

Table 1. Concentration of E. coli O157:H7 Inoculum Level per Gram of Matrix, Determined through Most Probable Number Analysis

Sample Size Sample Number Number of Positives MPN/g 1

95% CI 1

Food Matrix/Inoculation Level

100

5 5 5 5 5 5

4 1 2 3 5 3

1.107 X 10 -2 , 6.028 X 10 -2 2.494 X 10 -2 , 9.008 X 10 -2

2.584 X 10 -2

Spinach/High

10

1

50 25 10

4.740 X 10 -2

Sprouts/High

1. MPN/g and 95% Confidence Interval Values were generated from the LCF MPN Calculator Version 1.6

Table 2. Candidate Method Testing Results for Spinach Matrix ‘Screening Stage’ and ‘Confirmation Stage’ (200 g Spinach Analyzed via the 3M TM MDA)

3M MDS 18 h

Sample Number

Inoculum Level

CT-SMAC #1 CT-SMAC #2

Rainbow

O Serology H Serology

VITEK Confirmation

+ = = = = = = + = = = = + + = = = + + + + + + + + = = = = =

+ = = = = = = + = = = = + + = = = + + + + + + + + = = = = =

+ = = = = = = + = = = = + + = = = + + + + + + + + = = = = =

+ = = = = = = + = = = = + + = = = + + + + + + + + = = = = =

+ = = = = = = + = = = = + + = = = + + + + + + + + = = = = =

+

E. coli O157

+ = = = = = = + = = = = + + = = = + + + + + + + + = = = = =

1 2 3 4 5 6 7 8 9

LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW LOW HIGH HIGH HIGH HIGH HIGH

+

E. coli O157

10 11 12 13 14 15 16 17 18 19 20

+ +

E. coli O157 E. coli O157

+ + + + + + + +

E. coli O157 E. coli O157 E. coli O157 E. coli O157 E. coli O157 E. coli O157 E. coli O157 E. coli O157

1 2 3 4 5 1 2 3 4 5

UNINOC UNINOC UNINOC UNINOC UNINOC

CONFIDENTIAL INFORMATION Page 7 of 17