MODIFICATIONS TO 

EXISTING AOAC OFFICIAL 

METHODSSM

2011 UDM/OECD Technical Workshop

U.S. Environmental Protection Agency

Fort Meade, MD

November 15 & 16, 2011 

Jafrul Hasan

OPP Microbiology Laboratory, EPA
Editorial Changes

• An editorial change is a correction or clarification of 

language or expression, and no study data are needed

• No method validation is required, but written record of 

action will be filed

• If a method is modified editorially, it retains its First or 

Final Action Status

• The AOAC Methods Committee on Antimicrobial Efficacy 

Testing (Committee M) must approve editorial changes

AOAC INTERNATIONAL Official MethodsSM of Analysis Program Manual, Part 5, 2004

AOAC INTERNATIONAL 2
Editorial Changes – Examples 

• Addition of non-technical information for consistency

• Updating of non-technical footnote or reference information

• Changes to titles of sections, tables, and figures

• Rearrangement or renumbering of sections, tables, and figures

• Minor changes in sentence structure that does not change the 

original intent

• Corrections of spelling or punctuation

• Addition of AOAC general safety caveat for materials and apparatus

• Correction of typographical errors that would not have otherwise 

affected the technical interpretation of the method

AOAC INTERNATIONAL Official MethodsSM of Analysis Program Manual, Part 5, 2004

AOAC INTERNATIONAL 3
Minor Change

• A minor change in procedural parameters is one that 

does not affect the methods performance and does not 

require new in-house data

• By scientific judgment of the Methods Committee, 

literature or historical data are sufficient validation

• A method with a minor change retains its First or Final 

action status

• The Methods Committee must approve minor changes

AOAC INTERNATIONAL Official MethodsSM of Analysis Program Manual, Part 5, 2004

AOAC INTERNATIONAL 4
Procedure Modification

• A procedure modification that does not change the principle of 

the method but may affect the performance parameters 

requires an in-house comparative study of the old and new 

procedure that demonstrates equivalent or improved method 

performance

• A comparative study can be in-house or multi-laboratory, but 

must be of sufficient scope to establish equivalency of 

performance as determined by the Methods Committee

• The comparison may take place against original collaborative 

study data

• The Methods Committee must approve a procedure 

modification

AOAC INTERNATIONAL Official MethodsSM of Analysis Program Manual, Part 5, 2004

AOAC INTERNATIONAL 5
Procedure Modification

• Procedure modifications include changes in the 

procedure, instrument, reagent, or parameter that does 

not change the principle of the method but may affect the 

performance parameters

• A modified First Action method receives a new date of 

First Action; a modified Final Action method reverts to 

First Action

• Procedure modifications will be listed in Changes in 

Official Methods SM and the method will be modified

• Method status will also be revised

AOAC INTERNATIONAL Official MethodsSM of Analysis Program Manual, Part 5, 2004

AOAC INTERNATIONAL 6
Modifications to Existing Official MethodsSM

• All procedures for method approval must be followed, 

including submission of study protocol

• The approved revised (new) method will be included in the 

Inside Laboratory Management (Changes in Official Methods

SM), along with notice of Repeal or Surplus status of replaced 

(old) method

• Statistical performance parameters listed with a method 

remain unchanged with a method modification unless the 

study of the modification allows the generation of new 

performance parameters

AOAC INTERNATIONAL Official MethodsSM of Analysis Program Manual, Part 5, 2004

AOAC INTERNATIONAL 7