AOACSPIFANMethods-2017Awards

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B olong et al .: J ournal of AOAC I nternational V ol . 99, N o . 1, 2016  203

chloride content is skim milk powder. Data from routine testing of skimmilk powder, with sample identity blinded, are presented in Table 7. The practical analytical range based on real-world samples is 28.5 to 1080 mg/100 g on an “as is” basis (although the practical upper analytical range is likely much higher) and meets the requirement of SMPR 2014.015 of 5 mg/100 g to 500 mg/100 g in ready-to-feed or reconstituted basis.

In routine testing, desalted whey powder D90 has been found to have the lowest chloride content. Data from routine testing of this product type, with sample identity blinded, are shown in Table 6. Precision across the three samples meets the reproducibility requirement, validating the LOQ in the range 27.8 to 29.5 mg/100 g. The validated LOQ does not meet the SMPR requirement of ≤5 mg/100 g, but this cannot be tested without appropriately low samples. Commercial table salt can be used to test the upper limit of the analytical range of the potentiometric titration method, demonstrating an upper limit of 99.0 to 99.5% (data not shown). In routine testing, however, the matrix with the highest observed Table 6. LOQ determination using desalted whey powder Sample No. Average result, mg/100 g Reproducibility (RSD), % 1 27.8 2 28.2 3.1 3 29.5 Analytical Range

Conclusions

The data presented from this single-laboratory validation study demonstrate that the method meets the criteria outlined in SMPR 2014.015 and supports First Action status of the method.

References

(1) Official Methods of Analysis (2012) 19th Ed., AOAC INTERNATIONAL, Gaithersburg, Rockville MD, AOAC SMPR 2014.015, www.eoma.aoac.org (2) GB 5413.24-2010, National Food Safety Standard Determination of Chlorine in Foods for Infants and Young Children, Milk and Milk Products, http://www.moh.gov.cn/ zwgkzt/psp/201005/47460.shtml (3) GB/T 6682-2008, Water for Analytical Laboratory Use— Specification and Test Methods, http://www.sac.gov.cn/ SACSearch/search?channelid=97779&templet=gjcxjg_detail. jsp&searchword=STANDARD_CODE=%27GB/T%206682- 2008%27&XZ=T (4) GB/T 601-2002, Chemical Reagent—Preparations of Standard Volumetric Solutions, http://www.sac.gov.cn/ SACSearch/search?channelid=97779&templet=gjcxjg_detail. jsp&searchword=STANDARD_CODE=%27GB/T% 20601-2002%27&XZ=T.

Table 7. Skim milk powder data Sample No.

Average result, mg/100 g Reproducibility (RSD), %

1 2 3

1070 1080 1020

3.0