# Determination of β-Galactooligosaccharides (GOS) in Infant Formula: Collaborative Study, Final Action 2021.01

## TL;DR

This study confirms the reliability of a method for measuring β-galactooligosaccharides in infant formula across multiple labs.

## Contribution

The study provides reproducibility data to promote the GOS determination method to Final Action status by AOAC.

## Key findings

- Six infant formula samples met AOAC performance requirements with RSDr 1.4–4.7% and RSDR 8.1–11.6%.
- The adult nutritional sample exceeded AOAC reproducibility targets (RSDr 9.9%, RSDR 12.1%).
- 13 out of 14 labs successfully analyzed practice samples and contributed to the collaborative study.

## Abstract

We previously published a method for the determination of β-galactooligosaccharides (GOS) in infant formula and adult nutritionals, which is currently First Action AOAC Method 2021.01. In this study, reproducibility data were collected to support the promotion of the method to Final Action.

A collaborative study was organized in which 14 laboratories from eight different countries participated. Initially, laboratories were requested to analyze two practice samples and request guidance from the study director in case of issues. Successful laboratories proceeded to analyze seven samples (six infant formula and one adult nutritional) received as blind duplicates.

Thirteen laboratories reported acceptable results for practice sample 1. Practice sample 2 could only be delivered to eight of the laboratories due to restrictions at customs. The 13 laboratories successfully analyzing practice sample 1 were requested to continue with the analysis of the multilaboratory trial (MLT) samples. Laboratory 14 was unable to solve some technical difficulties, so their data could not be used. Out of the seven samples tested, results for six infant formulas met the requirements of the AOAC Standard Method Performance Requirements (SMPR®) 2014.003, with repeatability (RSDr) ranging from 1.4 to 4.7% and reproducibility (RSDR) ranging from 8.1 to 11.6%. The adult nutritional sample returned results outside the range of the SMPR, having an RSDr of 9.9%, higher than the SMPR target of ≤6%, and an RSDR of 12.1%, just above the SMPR target of ≤12%.

The method described is suitable for the determination of GOS in infant formula.

A method is described which is suitable for the determination of GOS in infant formula.