AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (Jan. 2019) FOS-03 MLT Report FOR ERP USE ONLY DO NOT DISTRIBUTE

Table 7. Comparison of results with and without blank subtraction

Mean with blank subtraction, g/100 g b

Mean without blank subtraction, g/100 g b

P- value c

Significantly different?

n a

Sample name

No

SRM 1869 d

12

0.209

0.217

0.27

No

Adult nutritional RTF e (1)

12

1.28

1.33

1.3

No

Adult nutritional RTF e (2)

12

2.67

2.78

2.7

No

Infant formula RTF

12

0.300

0.315

0.41

No

Child formula powder f

12

0.275

0.286

0.20

No

Toddler formula powder milk-based f

12

0.209

0.219

0.18

No

Infant formula powder FOS/GOS based f

12

0.032

0.032

0.78

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 b Results are reported in g/100 g of product as consumed (reconstituted or RTF) 12 0.264 0.278 0.30

c T-test 2 sided (hyp=unpaired, equal variance) d Reconstitution rate: 10 g product + 90 g water e RTF = Ready-to-feed f Reconstitution rate: 25 g product + 200 g water

Method adaptations by MLT participants The participants were asked to report any deviations from the MLT protocol and they were numerous. Regarding the sample reconstitutions, one lab downsized the reconstitution rate to 15.0 g product + 120.0 g water because containers of appropriate dimensions were not available, but the ratios were preserved. Another participant applied a different reconstitution protocol by weighing 12.5 g of powder and adding 100 mL of water (using a volumetric flask) or weighing 10 g of powder and adding 90 mL of water (using a measuring cylinder) for SRM1869. Several participants did not understand the importance of the precision of the reconstitution rates and applied inconsistent ratios of powder/water. To remedy this, which would lead to artificially elevated precision data, reconstitution weights were requested from all participating labs and the final fructan results corrected accordingly. In one laboratory, the solution “A” was diluted by weight instead of by volume. Regarding optional Carrez clarification, 4 labs used it and 7 labs did not. One participant performed both procedures (with and without Carrez clarification), but only the data without clarification were used for data analysis as one sample result was missing for the procedure with Carrez clarification (results with and without Carrez treatment were comparable). Several labs mentioned they had to use slight positive pressure or pump assist in order to help elution from the SPE columns. This remark has been added in the final method. Regarding chromatography, a lot of deviations were mentioned by the participants. Only 3 labs did not deviate from the chromatographic conditions described in the protocol. Eight participants used a PA1 column, 2 labs used a PA20, 1 lab used a PA10 and 1 lab used