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

Fortified micro- organisms ATCC No.

95% CI e

Matrix

Cont. level

Mean diff. d

r 2h

Candidate Method

Reference Method

Mean a

s r b

RSD r c

Mean a

s r b

RSD r c

LCL f

UCL g

<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 13

Serratia marcescens ATCC 13880 (48% heat stress injury)

1.573 2.873 5.535 1.547 4.931 5.486 1.316 3.044 3.991 1.827 2.451 3.459 1.419 3.528 4.479 <0.1 <0.1 <0.1

0.207 0.120 0.096 0.303 0.048 0.134 0.331 0.018 0.035 0.361 0.083 0.294 0.377 0.051 0.054 na na na

1.664 3.075 5.458 1.551 5.042 5.560 0.979 3.059 3.936 1.942 2.430 3.524 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 0.519 0.271 0.139 0.058 na na na

0 3 4

-0.091 -0.202 0.077 -0.004 -0.111 -0.074 na

-0.348 -0.354 -0.262 -0.242 0.190 -0.314 -0.229 -0.047 -0.006 -0.286 -0.257 -0.380 -0.368 -0.167 -0.197 na na na

0.166 -0.050 0.108 0.233 0.033 0.166 -0.444 0.019 0.116 0.056 0.299 0.251 -0.047 0.104 0.027 na na na

Unsalted butter

0.998

4 2

na 10

na 20

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

Vanilla ice cream

0.998

1 2

1 4

na 43

na

na 25

Soy infant formula

0.34 -0.01 0.06

0.996

1 1

1 1

20

23 12 15 na 17

-0.115 0.021 -0.065 -0.208 -0.031 -0.085 na

Chicken Rinse in BPW

Natural Contamination

3 8

0.993

na 27

Citrobacter freundii ATCC 8090 (Lyophilized)

Rice Infant cereal

0.999

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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