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food manufacturers, food regulatory agencies, food research institutes, and private laboratories, was decided after satisfactory results were shown on the training sample (a milk powder used also in the collaborative study), and satisfactory chromatographic resolution between C18:1 cis and trans isomers, which is essential for the accurate determination of TFAs in dairy products. The six samples selected by SPIFAN were shipped to participants from Covance Laboratories (Madison, WI), and the six other samples selected by ISO-IDF were shipped to participants from Nestlé (Lausanne, Switzerland) are listed in Table 1. Each participant recorded data on a single template that contained sections for reporting all raw data and fatty acid calculations and for including chromatograms and comments. The protocol was based on AOAC First Action Method 2012.13 for analyzing infant formula and adult/pediatric nutritional products and on the ISO-IDF method for analyzing dairy matrixes (i.e., cheese sample). AOAC Official Method 2012.13 Determination of Labeled Fatty Acids Content in Milk Products, Infant Formula (and Adult/Pediatric Nutritional Formula) Capillary Gas Chromatography Method

chromatographic capillary column of 100 m long has been developed for its use in various laboratories using different GC equipment and different types of injectors. The response factors of the equipment have been taken into account in the calculations to provide quantitative fatty acids results. The method has already been implemented in several laboratories, and their performance has been regularly evaluated and monitored via proficiency tests. The method was also published in a scientific paper (1) before being proposed for the standardization process, first with the International Organization for Standardization (ISO)–International Dairy Federation (IDF) as a NewWork Item proposal moved forward to an International Standard (2). In view of the absence of an internationally recognized analytical method for fatty acids in the selected SPIFAN matrixes, the method proposed to ISO-IDF was identified as a good candidate to meet AOAC Standard Method Performance Requirement (SMPR ® ) 2012.011 (3, 4) defined by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN). In the frame of the agreement between ISO and AOAC to develop common standards (signed June 18, 2012), it was decided to merge the two activities to avoid duplicate work. To verify the method performance for SPIFAN-selected matrixes, a single-laboratory validation (SLV) study was performed on all samples (SPIFAN test kit of 12 samples). After evaluation of the SLV data, an AOAC Expert Review Panel (ERP) determined that the method met SMPR 2012.011 as approved by SPIFAN. The ERP granted the method Official First Action status on October 2, 2012 (5) and SLV results were then published separately (6). The method was recommended to advance to multilaboratory collaborative study for the evaluation of reproducibility (7).

First Action 2012 Final Action 2014 ISO/IDF-AOAC Method

A. Scope

Collaborative Study

The method is applicable to the determination of all fatty acids, including individual labeled fatty acids [i.e., linoleic acid (LA), α-linoleic acid (ALA), arachidonic acid (ARA), ecosapentaenoic acid (EPA), and docosahexaenoic acid (DHA)] and/or group of fatty acids [i.e., trans fatty acids (TFAs), saturated fatty acids (SFAs), nonounsaturated fatty acids (MUFAs), polyunsaturated fatty acid (PUFAs), omega-3,

Although more than 30 laboratories initially indicated their potential interest for involvement in this study, some were not considered principally due to their location, difficulties in shipping dairy samples, and time or resource constrains. The final enrollment of participating laboratories, which included

Table 1. Collaborative study samples and codes

Sample A MLT code b GHXZ007 JSYB023 KLMQ050 DDHU078 MJFR034 SZEC013 LARU224 LUJP087 YKLP059 MOPG098 LHTK069 VFJL091

Sample B MLT code SJLO002 GPOQ091 SYKA045 UYBE089 WHTF002 VCIN029 GLVC238 ADVZ021 ZNPI092 SJLQ035 LKAU043

Sample No. a

Product

Fat, %

1 2 3 4 5 6 7 8 9

Full cream (milk powder) Full cream (liquid milk)

26.27

3.55

Full cream

35.27 82.93 13.29 25.67 17.44 26.01 28.38

Butter

Cheese (soft)

Infant formula (powder)

Adult nutritional (milk-protein powder)

Infant formula (partially hydrolyzed soy powder) Infant formula (milk-based powder) Infant formula RTF (milk-based liquid) Adult nutritional RTF (high-protein liquid) Adult nutritional RTF (high-fat liquid)

10 11 12

3.57 3.58 8.61

YATV077 a  Sample Nos. 1 to 6 were selected by ISO-IDF and shipped from Nestlé (Lausanne, Switzerland); Sample Nos. 7 to 12 were selected by SPIFAN and shipped from Covance (Madison, WI). Analysis was performed on duplicate samples (A and B). b  MLT = Multilaboratory testing.