AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (October 2019) – FOS-03 MANUSCRIPT

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MLT Samples 2 The analytical results submitted by the 12 participants on the MLT samples were analysed and 3 the results of the statistical evaluation are shown in Table 4 . The full set of data per laboratory and 4 per sample are reported in Tables 5 and 6 . The main purpose of the study was to collect precision 5 data, however results on SRM 1869 (0.204 g/100 g) can be compared with the available reference 6 value (not certified) (0.212 ± 0.085 g/100 g) and shows good agreement, demonstrating 7 satisfactory accuracy of the method. The mean fructan concentrations in the infant formula and 8 adult nutritionals analysed in this study were in the range 0.0308 to 2.67 g/100 g of reconstituted 9 final products, which corresponds to the lowest level required in the SMPR 2014.002 and to the 10 highest level commercially available, respectively. Repeatability and reproducibility were not 11 always well within the limits stated in the SMPR 2014.002. Values of RSD r ranged from 2.27 % to 12 7.65 % and RSD R were between 5.90 % and 15.1 %. Only one product had both repeatability and 13 reproducibility values slightly higher than the requirement (7.65 % and 12.8 % respectively) and 2 14 other samples showed reproducibility values higher than SMPR (15.1 % and 14.6 %). Two out of 15 these three products were liquid samples, which presented a deposit on the bottom of the container. 16 It could be that if the samples were not well agitated these samples could present an inhomogeneity. 17 However considering the numerous deviations applied to the MLT protocol by the participants and 18 the wide range of chromatographic conditions used, these precision data demonstrate a rather robust 19 method. For most of the samples, all 12 participants’ results were included for statistical analysis. 20 Only 3 outliers were removed prior to statistical analysis based on Cochran’s and Grubbs’ tests. 21 Lab 2 was an outlier according to single Grubbs’ test for SRM 1869 as well as for infant formula 22 powder FOS/GOS, and Lab 8 was an outlier according to Cochran’s test for infant formula powder 23 FOS/GOS sample. Without removing these outliers, the RSD r and RSD R would have been 4.41 % 24 and 10.2 % respectively for SRM 1869, and 8.19 % and 20.8 % respectively for infant formula 25 powder FOS/GOS. Horwitz ratio (HorRat) values were also estimated and ranged from 1.2 to 3.3. 26

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