AOAC Methods Review (Codex STAN 234)

9. Is the method information accurate?

Yes

10. Is the method fit for purpose to measure the provision as listed in the commodity standard?

No

10a. Please provide information

This is a qualified "no". The figures of merit are not commensurate with assignment of Type II status for Cu, Mn, and Zn. A better alternative is AOAC 2015.06. In contrast to AOAC 984.27, however, this method is still being used (judging from my numerous contacts with TPLs) in a way that is close to the written method and still provides useful results, so should be retained as Type III for all 8 analytes (it is not currently in the CODEX standard for Na and K but could be).

11. Is the method fit for purpose according to technical evaluation? 11a. Please provide information on technical evaluation

No

This is a qualified "no". There is no validation data for pet food (which would not be in the CODEX standard), and it's never mentioned in the discussion so I'm not sure why it's in the title. CODEX has this method listed as Type III for Ca, Fe, Mg, and Type II for Cu, Mn, and Zn in infant formula as well as Type II for Cu in edible caseins and whey powders. The AAS method cannot determine P and cannot use an internal standard which is vital to have for a robust Type II method. There is no mention of required linearity, check standards, required control sample or any other system suitability. Dry ashing may lead to under-recovery of elements that form stable oxides and are difficult to re-dissolve in acid, and we have seen low recoveries for copper, iron and manganese before with such methods. Microwave closed- vessel digestion is the modern technique of choice.

For extended study, every element had at least one of eight labs rejected, and Ca and Fe had two - this indicates the method is relatively non-robust.

12.Is the method listed alongside any other methods in CXS 234?

No

13. Is further review of this method needed?

No

13b. 1. If no, please provide final recommendation for CXS 234, considering only the method under review 13b. 2. If no, please provide final recommendation for CXS 234, considering all methods listed for this commodity and provision

No change

Have AOAC change the name to delete Pet Foods and add Whey Powder. In CODEX STAN 234-1999, assign this method Type III status for all eight elements in Infant Formula, replace the Type II vacancies with 2015.06 (a separate initiative).