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Bolong et al.: Journal of AOAC International Vol. 99, N o. 1, 2016 203
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.
Analytical Range
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
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.
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
(2) GB 5413.24-2010, National Food Safety Standard
Determination of Chlorine in Foods for Infants and Young
Children, Milk and Milk Products,
(3) GB/T 6682-2008, Water for Analytical Laboratory Use—
Specification and Test Methods
(4) GB/T 601-2002, Chemical Reagent—Preparations of
Standard Volumetric Solutions,
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
Table 7. Skim milk powder data
Sample No. Average result, mg/100 g Reproducibility (RSD), %
1 1070
2 1080 3.0
3 1020
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