AOAC Adopts Two New Methods for MCPD/GE

On July 19, 2018, the AOAC Expert Review Panel (ERP) for SPIFAN 2- and 3-Monochloro-1,2-Propanediol (MCPD) and Glycidyl Esters (GE) adopted two new methods applicable to infant formula and adult/pediatric nutritional formula as First Action Official MethodsSM. The ERP, chaired by Katerina Mastovska of Eurofins Food Integrity and Innovation, agreed that the methods meet AOAC Standard Method Performance Requirements (SMPRs®) developed and approved through voluntary stakeholder consensus.

The project is supported by the Infant Formula Council of America (INCA). Esters of 2- and 3- MCPD and glycidol are contaminants of processed vegetable oils. The presence of free or bound 2-MCPD, 3-MCPD, and glycidol can pose risk to human health. Glycidol, considered the most problematic of these compounds, is probably carcinogenic to humans (IARC group 2A carcinogen). Free 3-MCDP was discovered as a food contaminant in the 1970s and is possibly carcinogenic to humans (IARC group 2B carcinogen).

Erik Konings of Nestlé explains the importance and timeliness of AOAC standards development activities in this area, stating “MCPDE/GE are possibly carcinogenic/genotoxic substances occurring in refined oils and, therefore, in foods containing added fats. Food safety authorities worldwide are actively collecting MCPDE/GE occurrence data for safety assessment and setting maximum limits for, among others, infant formula serving a sensitive population. In February 2018 new European Regulation on maximum levels of GE in infant formula was published. In absence of (collaboratively) validated (Official) methods to check compliance to this regulation, it is evident that AOAC SMPRs, including regulatory levels, and two designated AOAC Official MethodsSM meeting these requirements are important for the global regulatory and food safety landscape.”

Mastovska adds, "AOAC developed SMPRs for determination of 2- and 3-MCPD, 2- and 3-MCPD esters, and GE in infant formula and adult/pediatric nutritional formula to meet EU regulation and to facilitate routine monitoring. The two methods adopted as First Action by AOAC are high-quality, reliable, accurate, and sensitive for the analysis of these important processing contaminants and meet the new EU Regulation 2018/290."

The ERP initially reviewed the methods on March 14, 2018, during the AOAC Mid-Year Meeting. Although the methods showed much promise, the ERP reached consensus that additional information was needed prior to First Action Official MethodsSM consideration. Authors submitted supplemental documentation, and in July 2018, the ERP again provided in-depth reviews of the methods.

Candidate methods were evaluated against SMPRs developed and approved by voluntary consensus of the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN). All methods were reviewed by a primary and secondary expert reviewer. Panel members summarized their reviews, and advantages and disadvantages of each method were then discussed thoroughly by the entire panel, stakeholders, and observers present. Technical issues, as well as general comments, were addressed and reconciled.

A balance of experts and international representation was integral to the ERP. Panel members were thoroughly vetted by the AOAC Official Methods Board (OMB).

In general, based on their collective expertise and judgment, the ERP agreed that method performance characteristics for both methods met SMPRs as established by SPIFAN. Recommendations and comments were addressed through the additional experiments. Results of the SLV and additional data support First Action adoption of the methods.

Submitted by Nestlé (an AOAC Organizational Affiliate), “Fatty Acid Esters of 2-Chloropropane-1,3-Diol (2-MCPD), 3-Chloropropane-1,2-Diol (3-MCPD) and Glycidol, Free 2-MCPD and Free 3-MCPD in Infant Formula and Adult/Pediatric Nutritional Formula” describes a single-laboratory validated (SLV) method in which fat from infant or nutritional formula is first extracted by a liquid-liquid extraction using ethyl acetate. Analysis of 2-MCPD esters, 3-MCPD esters, and GE in the extracted fat is performed using GC-MS/MS. Analysis of free 2-MCPD and 3-MCPD is performed by a separate procedure.

Overall, the ERP agreed that the method is of high quality, scientifically sound, and properly validated. Method clarity is good, and calculations are straightforward. The fat extraction procedure has been validated against the established Rose-Gottlieb method in a wide variety of matrices. Determination of 2-MCPD esters, 3-MCPD esters, and GEs in the extracted fat is performed by an officially recognized method (AOCS Cd 29a-13). The procedure for the separate determination of free 2-MCPD and 3-MCPD has also been properly validated.

In “2-Monochloropropanediol (2-MCPD), 3-Monochloropropanediol (3-MCPD), and Glycidol in Infant and Adult/Pediatric Nutritional Formula,” submitted by SGS Germany GmbH, an SLV of the method is described using GC-MS and the suite of SPIFAN matrices. Extraction of fat from powders is performed by heat ultrasonic pressure supported solvent extraction (HUPsSE), which extracts both free and bound (esterified) 2-MCPD, 3-MCPD, and glycidol. The single extract is partitioned into an organic phase and an aqueous phase. 2-MCPD esters, 3-MCPD esters, and GEs are determined in the organic phase by the AOCS Cd 29b-13 method. Free 2-MCPD and 3-MCPD are determined in the aqueous phase by a separate procedure.

In general, the ERP agreed that method validation was well done, data are good, and the method is detailed. The method was proven to be applicable for the separate determination of free and bound analytes and showed sufficient specificity and trueness in liquid and powdered infant formulae.

First Action methods will be published in the Official Methods of AnalysisSM and the Journal of AOAC INTERNATIONAL. The ERP will monitor these methods for the next 2 years as they work their way toward Final Action status consideration. AOAC also solicits user feedback on all First Action methods. If the methods demonstrate acceptable reproducibility as outlined in the SMPR, and feedback is positive on method performance and use, the ERP will recommend the methods for Final Action Official MethodSM status consideration by the OMB.

For more information on AOAC SPIFAN, visit > Standards Development > Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) or contact Alicia Meiklejohn, director, business development and governance, at


AOAC SPIFAN MCPD/GE Expert Review Panel

Katerina Mastovska (Chair), Eurofins Food Integrity and Innovation

Mathieu Dubois, Nestlé

Stefan Ehling, Abbott Nutrition

Greg Jaudzems, Nestlé USA, Inc.

Jan Kuhlmann, SGS Germany GmbH

Jessica Leigh, U.S. Food and Drug Administration (FDA)

Celine Lesueur, Danone

Shaun MacMahon, FDA Center for Food Safety and Applied Nutrition

Salvatore Parisi, COIF Association, Italy

Joe Romano, Waters Corp.

Cheryl Stephenson, Eurofins Central Analytical Laboratory

Sudhakar Yadlapalli, First Source Laboratory Solutions LLP

Jie Zhang, Mead Johnson Nutrition