AOAC OMB Final Action Recommendation (December 2019)-2016.14

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

Introduction Fructans are a class of carbohydrate polymers composed predominantly of fructose monomers. In the food industry the inulin-type fructans, which are composed predominantly of β-2,1-linked fructose units, are widely used as a source of dietary fibre or prebiotics and have been associated with a number of health benefits [1-3]. A number of analytical methods have been developed for the analysis of fructans in food products and have been extensively discussed in previous papers [4,5]. Historically only two official methods for the determination of fructans in food products have been available, AOAC 997.08 [6] and AOAC 999.03 [7]. Both of those methods have their limitations, which have previously been discussed [4,5,8], and this lead to a call for new methods, initiated by the Stakeholder Panel for Infant Formula and Adult Nutritionals (SPIFAN) after defining the standard method performance requirements (SMPR) for fructan analysis [9]. Of the methods submitted to the AOAC in answer to the call for methods, two methods had sufficient single laboratory performance to be promoted to first action status; the method submitted by Haselberger and Jacobs [8], first action 2016.06 and the method submitted by Brunt, et.al. [5], first action 2016.14. This report describes the multi-lab trial carried out to test the performance Twenty-nine laboratories were invited to participate in this collaborative study and 15 laboratories located in 12 different countries expressed interest in participating. One lab had to resign because of difficulties in importation of the milk samples and two labs dropped out because of instrumentation problems and resource availability. Finally, 12 laboratories from 9 countries managed to provide results on time for this study. The study was designed in two parts (1) Method set up and qualification of participants and (2) Multi-laboratory test participation, detailed in the study protocol accompanying the sample kit. The five fructan-containing infant formula from the SPIFAN kit were used in the study and an additional two adult nutritional products and one ready-to-feed (RTF) infant formula from manufacturing sites in Europe were added. A Standard Reference Material (SRM 1869 Infant/Adult Nutritional Formula) from the National Institute of Standards and Technology (Gaithersburg, MD) was also included. The additional samples were added to the SPIFAN kit because only five of the products in the kit contained fructans. All samples were blinded and coded before being dispatched to the participants. Homogeneity of the fructan contents in the extra samples was assessed by duplicate analyses of test samples from separate bottles. Out of the 5 boxes of 24 bottles each, received for the RTF infant formula (120 bottles), one bottle was randomly selected in each box and analysed in duplicate for its fructan content ( n =5). The 2 adult nutritional products were received in 4 boxes, each containing 6 packs of 4 bottles (96 bottles). From each box, one bottle was randomly selected as well as 2 additional bottles among the 4 boxes, and analysed in duplicate for their fructan contents ( n =6 ). Statistical analysis was performed using the Cochran test according to the ISO 5725-2:1994 norm. The between sample variability was demonstrated to be zero for the 3 products (data not shown). On this basis, the samples were confirmed to be homogeneous for their fructan contents, thus fit for purpose to be included in the collaborative study. The kits of samples were shipped at ambient temperature. The participants were asked to keep the samples at room temperature before undertaking analysis and once opened, to keep them in tightly closed containers for the duration of the study. The liquid products had to be kept at 4 °C once opened. of first action method AOAC 2016.14. Collaborative Study Description