AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (October 2019) – FOS-03 MANUSCRIPT

FOR ERP USE ONLY DO NOT DISTRIBUTE

Blank measurements 1 According to the experience gained through the Single Lab Validation (SLV) [5] and as 2 described in the method, “a blank measurement is only necessary for some matrices and may be 3 skipped if it has already been established that the blank measurement has a negligible impact on 4 the result of a given matrix”. As all samples in this study were unknown, participating laboratories 5 made blank measurements for every sample. The variations of the blank measurements between 6 the participants were high and it was questionable if the signals in the blanks were of sufficient size 7 to be above the limit of quantitation (LoQ). The mean results with blank measurements subtracted 8 were compared with the mean results obtained without subtracting blank measurements using an 9 unpaired t-test. As can be seen from the p-values depicted in Table 7 , the mean results of the 10 samples are not statistically different, whether the blank measurement is subtracted or not. This 11 demonstrates that for these matrices a blank subtraction was probably not necessary. 12 13 Table 7. Comparison of results with and without blank subtraction 14

Mean with blank subtraction, g/100 g b

Mean without blank subtraction, g/100 g b

P- value c

Significantly different ?

Sample name

n a

SRM 1869 d

12 12 12 12 12 12 12 12

0.209

0.217

0.27

No No No No No No No

Adult nutritional RTF e (1) Adult nutritional RTF e (2) Infant formula RTF Child formula powder f

1.28 2.67

1.33 2.78

1.3 2.7

0.300 0.275 0.209 0.032 0.264

0.315 0.286 0.219 0.032 0.278

0.41 0.20 0.18 0.78 0.30

Toddler formula powder milk-based f Infant formula powder FOS/GOS based f Infant formula powder milk based f

No a Number of laboratories considered in the evaluation. All data have been used for the calculation, no outliers removed. 15 b Results are reported in g/100 g of product as consumed (reconstituted or RTF). 16 c T-test 2 sided (hyp=unpaired, equal variance) 17 d Reconstitution rate: 10 g product + 90 g water. 18 e RTF = Ready-to-feed 19 f Reconstitution rate: 25 g product + 200 g water.

20 21 22

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