AOAC ERP MICRO AUGUST 2018

OMAMAN-44 A: Collaborative Study Manuscript Expert Review Panel Use Only August 2018

Pre-collaborative and Collaborative Report Peel Plate EB

Table 6. Continued - Peel Plate-EB Method (Singlet count) for Enterobacteriaceae at 48 hours vs ISO Methods 21528-1 and 2.

Fortified micro- organisms ATCC No. Serratia marcescens ATCC 13880 (48% heat stress injury) Klebsiella oxytoca ATCC 700324 (42% heat stress injury) Enterobacter aerogenes ATCC 13048 (20% heat stress injury)

Cont. level

Candidate Method

Reference Method

95% CI e

Matrix

r 2 h

Mean diff. d

Mean a

Mean a

s r

RSD r

s r

RSD r

LCL f

UCL g

b

c

b

c

None

<0.1 1.552 2.867 5.472 <0.1 1.557 4.935 5.515 <0.1 1.290 3.055 4.000 1.839 2.458 3.462 <0.1 1.839 2.458 3.462

na

na 19

<0.1 1.664 3.075 5.458 <0.1 1.551 5.042 5.560 <0.1 0.979 3.059 3.936 1.942 2.430 3.524 <0.1 1.942 2.430 3.524

na

na

na

na

na

unsalted butter

0 3 4

0.998

low mid high low mid high low mid high low mid high low mid high

0.294 0.124 0.109 0.376 0.043 0.155 0.417 0.022 0.038 0.351 0.081 0.315 0.351 0.081 0.315 na na na

0.000 0.085 0.196 0.154 0.037 0.197 0.417 0.026 0.041 0.440 0.286 0.519 0.440 0.286 0.519 na na na

-0.112 -0.208 0.013 0.006 -0.107 -0.045 0.311 -0.004 0.064 -0.103 0.028 -0.062 -0.103 0.028 -0.062 na na na

-0.477 -0.369 -0.199 -0.298 -0.174 -0.303 0.139 -0.058 -0.007 -0.274 -0.303 -0.410 -0.068 -0.360 -0.286 na na na

0.254 -0.047 0.226 0.309 -0.039 0.212 0.482 0.050 0.135 0.068 0.360 0.286 0.274 0.303 0.410 na na na

4 2

None

na 24

na 10

vanilla ice cream

0.999

1 3

1 4

None

na 32

na 43

Soy infant formula Chicken Rinse in BPW

0.997

1 1

1 1

19

23 12 15 na 23 12 15

Natural Contamination

3 9

0.995

None

na 19

Citrobacter freundii ATCC 8090 (Lyophilized)

rice Infant cereal

0.998

3 9

a Mean of 5 replicate portions, plated in duplicate, after logarithmic transformation: Log 10 [CFU/g + (0.1)f]. b Repeatability standard deviation. c Relative standard deviation for repeatability. d Mean difference between the candidate and reference methods. e Confidence interval. f 95% Lower confidence limit for difference of means.

g 95% Upper confidence limit for difference of means ERP Use Only i na- not applicable j Independent lab performed

h Square of correlation coefficient.

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