AOAC OMB Final Action Recommendation (December 2019)-2016.14

2016.14 (October 2019) – FOS-03 METHOD

FOR ERP USE ONLY DO NOT DISTRIBUTE

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H.

Sample Preparation

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(a) Products on a ready-to-feed basis (RTF) and powder products inhomogeneous at the subgram

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level .—Reconstitute powder or liquid concentrates according to instructions. For example,

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accurately weigh 25 g ( m R

) of infant formula powder into an appropriate bottle, add 200 g water

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( V R ) and mix well at room temperature to form a homogeneous suspension. Proceed as described

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in H(b) .

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(b) Reconstituted products (as prepared above), or products sold as RTF .—Mix well to ensure

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homogeneity of the test portion. Weigh 9 g ( m A

) of sample into a 50-mL volumetric flask ( V A

). Add

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30 mL water and confirm the pH is between 5 - 9 (adapt if needed, using hydrochloric acid or

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sodium hydroxide). Heat at 80 °C with constant agitation for 20 min. Cool to room temperature

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and make up to the mark with water (this is “Solution A”). Proceed as described in H(d) .

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(c) Homogeneous powder products without prior reconstitution .—Weigh 1 g ( m A

) of powder into a

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50-mL volumetric flask ( V A

). Add 30 mL water and confirm the pH is between 5 – 9 (adapt if

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needed, using hydrochloric acid or sodium hydroxide). Heat at 80 °C with constant agitation for

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20 min. Cool to room temperature and complete to the mark with water (this is “Solution A”).

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Proceed as described in H(d) .

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(d) Dilution .—The solutions prepared above are further diluted depending on the expected fructan

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content (suggested dilutions are given in Table 2016.14C ) and the resulting solution is “Solution

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B”. 232 Table 2016.14C. Scheme for sample dilution depending on expected fructan content 233

Expected fructan content, g/100 g

Dilution

Dilution factor, D

Volume of Solution A, mL

Final Volume, mL

Powder

Ready-to-feed

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