Draft standard method performance requirements (SMPRs) for whey/casein proteins ratio in milk-based infant formula were developed by a working group and subsequently approved by the Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN). In addition, the working group identified candidate methods for whey/casein protein for possible SPIFAN endorsement and further evaluation and consideration by an AOAC expert review panel (ERP) for First Action adoption.

As approved by SPIFAN, methods must be able to determine total whey proteins, including hydrolyzed forms, as a percent of protein content (as defined by appropriate regulatory agencies), in milk-based infant formula products (including those from bovine milk and, if possible, milk of other species and products containing hydrolyzed casein). For the purpose of the SMPR, whey protein is defined as the proteinaceous components obtained from milk after removal of casein components by various processing technologies. Any analytical technique that meets the SMPR is acceptable. Methods must demonstrate an LOQ of ≤10 g/100 g protein over an analytical range of 20-100 g/100 g. Repeatability and reproducibility are ≤3 and ≤6%, respectively, over the analytical range. Recovery is 95-105% of theoretical whey protein content.

The working group, chaired by Lei Bao (Shan Dong Import-Export Inspection and Quarantine Bureau of China and president of the AOAC China Section) and Shane Rutherfurd (Massey University-Riddet Institute), identified four whey/casein protein methods. Two methods are based on LC-MS/MS and two are based on amino acid analysis.

The SMPR for whey/casein proteins ratio in infant formula, as approved by SPIFAN, has been codified (AOAC SMPR 2012.002) and was posted on the AOAC website on July 20, 2012, for public comment.

In September 2012, during the AOAC Annual Meeting and Exposition in Las Vegas, Nevada, USA, SPIFAN will review the candidate methods for possible endorsement. Once endorsed, an ERP will consider the candidate methods for possible First Action Official MethodsSM status. Methods must acceptably meet the SMPR for First Action approval.

For more information on AOAC’s infant formula initiative, visit http://www.aoac.org/SPIFAN/aoac.htm or contact Anita Mishra, executive for scientific business development, at amishra@aoac.org.

Full coverage appears in the July/August 2012 issue of Inside Laboratory Management.

Copyright 2011 AOAC INTERNATIONAL. All Rights Reserved. Comments, Questions, Concerns, e-mail: webmaster@aoac.org