AOAC-RI ERP Book MICRO.pdf

3M MDA 2

Listeria

species and

L. monocytogenes

Collaborative Study

OMA-2016-MONTH-XXX

5/4/16

6.0

Reporting Raw Data

6.1

Report data using the data report form in Appendix 9.2.

6.2

Upon completion of each food type, the laboratory will fax or email the

completed data form to the Study Director.

6.3

Copies of all related test results (data sheets, printouts and confirmation results)

should be retained by the collaborating labs for a minimum of one year.

7.0

Analyzing Raw Data

The resulting data will be analyzed by probability of detection (POD).

7.1

Probability of Detection (POD) -

POD is the proportion of positive analytical

outcomes for a qualitative method for a given matrix at a given analyte level or

concentration. POD is concentration dependent. Please see the revised

microbiology guidelines

for complete analysis information on POD calculations.

7.1.1

Calculate:

7.1.1.1 Estimate of repeatability - standard deviation (s

)

7.1.1.2 Determine POD values for each matrix and concentration - the

number of positive outcomes divided by the total number of trials.

7.1.1.3 Estimate of reproducibility – standard deviation of the laboratory

POD values (s

POD

) and confidence intervals.

7.1.1.4 Cross laboratory probability of detection (LPOD) – LPODs by

matrix and concentration with 95% confidence intervals for

candidate method (presumptive and confirmed) results.

7.1.1.5 Difference of cross-laboratory probability of detection (dLPOD) –

difference probability of detection is the difference between any

two LPOD values.

7.1.1.5.1

Estimate dLPOD

as the difference between the

candidate and reference LPOD values, include CIs.

7.1.1.5.2

Estimate dLPOD

as the difference between the

presumptive and confirmed LPOD values, include CIs.

7.1.1.5.3

If the CI of a dLPOD does not contain zero then the

difference is statistically significant

7.1.1.6 For each matrix, graph POD

, LPOD

and dLPOD

by level with

95% confidence intervals.

AOAC INTERNATIONAL Methods Committee Guidelines for Validation of Microbiological Methods for Food

and Environmental Surfaces (pre-publication document, 2012) Sharon Brunelle, Robert LaBudde, Maria Nelson,

and Paul Wehling

AOAC Research Institute

Expert Review Panel Use Only

OMAMAN-29/OMAMAN-30 Combined Collaborative Study Protocol

OMA ERP - June 2016

ERP Use Only