# 2011 UDM/OECD Technical Workshop

Procedural Revisions to the AOAC Use

- dilution Method Recommended Action Items and Timeline

Activity Type of Method Revision Format MLB Draft Completion EPA Internal Review Completion Anticipated Decision by AOAC

Maximum carrier
counts Procedural JAOAC Manuscript Complete Complete 01/31/2012

Collaborative data and

use of frozen stocks Procedural JAOAC Manuscript Draft underway 12/30/2011 01/31/2012 03/31/2012

Reassessment of the performance standard

–

the statistical model and outcome Procedural JAOAC Manuscript Draft underway 01/31/2011 02/29/2012 04/30/2012

Frozen stocks plus reducing daily subcultures from 3 to 1 Procedural Written request to AOAC 01/31/2011 02/29/2012 04/30/2012

Change 20 mL to 10 mL final test cultures Procedural Written request to AOAC 01/31/2011 02/29/2012 04/30/2012

# 2011 UDM/OECD Technical Workshop

Editorial Revisions to the AOAC Use

- dilution Method Recommended Action Items and Timeline

Activity Type of Method Revision Format MLB Draft Completion EPA Internal Review Completion Anticipated Decision by AOAC
Establish maximum time carriers remain in primary and hold at room temp Editorial Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Clarify step for swirling of carrier in the

disinfectant Editorial/video Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Clarify step for draining

of carrier/avoid upper part of tube while tapping Editorial/video Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Broth culture media

– use of SB for Sa and Pa (for new registrations) Editorial Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Timeframe for performing control counts (3 + 3) Editorial Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

# 2011 UDM/OECD Technical Workshop

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### Editorial Revisions to the AOAC Use

- dilution Method Recommended Action Items and Timeline

Activity Type of Method Revision Format MLB Draft Completion EPA Internal Review Completion Anticipated Decision by AOAC

Eliminate use of negative

tubes for neutralization Editorial Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Add note for recording results for subculture media not showing turbidity (DE) and streak isolation for confirmation Editorial Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Inspection of P.a . broth cultures and add vacuum removal; avoid collection of bottom layer Editorial/pictures Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Under additional guidance,

use of larger volumes of neutralizer if primary/secondary combination is not effective Editorial Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

Include step for draining inoculum from tube with carriers prior to removal Editorial Written request to AOAC 12/30/2011 1/31/2012 03/13/2012

# 2011 UDM/OECD Technical Workshop

Revisions to MLB SOP MB

- 05 (Use

- dilution Method) Recommended Action Items and Timeline

Activity Type of Method Revision Format MLB Draft Completion EPA Internal Review Completion Anticipated Decision by AOAC Use secondary subculture tubes

on an “as

- need basis” Revision to MLB SOP MB

- 05 SOP Revision 12/01/2011 12/31/2012 N/A

Evaluation of primary only and primary/secondary combinations Revision to MLB SOP MB

- 17 SOP Revision 12/01/2011 12/31/2012 N/A

# 2011 UDM/OECD Technical Workshop 

# OECD Method Issues

• Source(s) and specs for carriers

• Filter or plating...

– All treated and controls to be filtered

– Options for one versus the other



# • When to vortex...

– Protocol does not state!

– Briefly after neutralization...

– Then 30 sec



# • Performance Standards • Vortex for neutralization assay should be the same as the test

– 30 sec

• Inoculation of additional carriers

– runoff can be an issue

• Use of a positive displacement pipet for the disinfectant too

• Use of OD for monitoring titer of cultures

• What about bubbles?

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