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 4. Continued - Peel Plate-EB Method (Singlet count) for Enterobacteriaceae at 24 hours vs ISO Methods 21528-1 and 2.

Fortified micro- organisms ATCC No.

Candidate Method

Reference Method

95% CI e

Matrix

Cont. level

r 2 h

Mean a

s r b

RSD r c

Mean a

s r b

RSD r c

LCL f

UCL g

Mean diff. d

<0.1

na

na

na

na

na

None low mid high low mid high low mid high low mid high low mid high None None None

<0.1

na

na

Serratia marcescens ATCC 13880 (48% heat stress injury)

Unsalted butter

1.574 2.862 5.472 1.460 4.914 5.503 1.281 3.055 4.000 1.750 2.399 3.450 1.385 3.528 4.476 <0.1 <0.1 <0.1

0.146 0.121 0.109 0.345 0.054 0.143 0.398 0.022 0.038 0.379 0.146 0.332 0.376 0.051 0.051 na na na

9 4 2

1.664 3.075 5.458 1.551 5.042 5.560 0.979 3.059 3.936 1.942 2.430 3.480 1.627 3.559 4.564 <0.1 <0.1 <0.1

0.000 0.085 0.196 0.154 0.037 0.197 0.417 0.026 0.041 0.440 0.286 0.484 0.271 0.139 0.058 na na na

0 3 4

-0.090 -0.213 0.013 -0.091 -0.128 -0.057 0.302 -0.004 0.064 -0.192 -0.031 -0.029 -0.241 -0.031 -0.088 na na na

-0.272 -0.374 -0.199 -0.405 -0.206 -0.303 0.131 -0.058 -0.007 -0.340 -0.381 -0.364 -0.414 -0.167 -0.196 na na na

0.092 -0.052 0.216 0.224 -0.051 0.189 0.472 0.050 0.135 -0.044 0.320 0.305 -0.068 0.104 0.021 na na na

0.998

na 10

na 24

Klebsiella oxytoca ATCC 700324 (42% heat stress injury) Enterobacter aerogenes ATCC 13048 (20% heat stress injury)

Vanilla ice cream

0.999

1 3

1 4

na 43

na 31

Soy infant formula

0.997

1 1

1 1

22

23 12 14 na 17

Chicken Rinse in BPW

Natural Contamination

6

0.995

10 na 27

Citrobacter freundii ATCC 8090 (Lyophilized)

Rice Infant cereal

0.998

1 1

4 1

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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