H. W. WILEY AWARD ADDRESS:
Validated Reference Methods, Proficiency Testing, and Reference Materials
Have Delivered Reduced Uncertainty in Milk Payment Testing!
Monday, September 27, 2010, 1:00 pm–1:30 pm
David Barbano, Ph.D.
Winner of the 2010 Harvey Wiley Award
Professor of Food Science and Director of the Northeast Dairy Foods Research Center
Cornell University, Ithaca, New York

In the early 1980’s there were no standardized procedures, statistical guidelines, or uniform structure for interlaboratory studies for validation of analytical methods. At that time, associate referees (today called study directors) for AOAC collaborative studies were often frustrated because there were no clear and uniform expectations for the structure and the evaluation process for the results of collaborative studies. In addition, different organizations that conducted studies for validation of methods for official testing had different criteria and often a study of a method would be done under the auspice of one organization and another methods organization would not accept the results of that study. This was frustrating for both study directors and official methods organizations. The harmonization of the process for validation of analytical methods achieved by the AOACI/International Dairy Federation/International Standards Organization was a huge step forward for analytical chemistry and particularly for methods used by the dairy industry around the world. The performance and accuracy of methods used to determine payment of dairy farmers and for the buying and selling milk among companies can be an extremely contentious issue.

In the mid-1980’s the harmonized guidelines for collaborative studies provided a frame work to improve and document the performance of traditional analytical methods (ether extraction for fat, Kjeldahl for protein, oven drying for solids, and spectrophotometric method for lactose) used to calibrate high speed secondary electronic milk testing methods. After the harmonization of the process for validation of methods, then a harmonized system of proficiency testing was developed. As overnight refrigerated shipment of samples improved, coupled with electronic communication of results via e-mail and dedicated web sites, it became practical to routinely distribute perishable samples for proficiency studies and as reference materials for calibration of secondary methods.

Over the past 25 years, a collaborative program with the USDA Federal Milk Market Laboratories and industry laboratories to improve the within and between lab agreement (with RSD values for the methods less than 1%) both on reference chemistry methods and on infrared milk analyzers has been very successful. Proficiency testing supported by data analysis using Pareto diagrams, control charts, Euclidian distance plots of test results using milks formulated to have an orthogonal matrix of composition has achieved a major reduction in uncertainty of both reference and instrumental method results by providing a system of identification of the causes of poor method performance both in chemical and instrumental methods for milk testing. The system that has been developed for milk can serve as a model for other types of methods and sample matrices.

About Dr. Barbano
David Barbano is a professor of food science and director of the Northeast Dairy Foods Research Center at Cornell University. During his career, he has made major advances in membrane filtration, iodine in foods, and high-speed, high-throughput mid-infrared methods for determining fat, protein, and lactose in milk. More recently, he has been using microfiltration to separate the protein components of skim milk, leaving two water-soluble proteins in the filtrate: beta-lactoglobulin and alpha-lactalbumin. A large part of Barbano's work with AOAC involves rapid testing of milk for fat, protein, solids, and lactose. Much of his work involves collaborative studies to validate these methods. In the process, he also improved one of the gold-standard laboratory tests used as reference methods for validating the rapid tests.

A member of AOAC since 1986, Barbano has received Associate Referee of the Year Awards (1990, 1994, 1998) and a Fellows Award (1994). His other activities include American Dairy Science Association, Institute of Food Technologists, New York State Milk and Food Sanitarians, International Milk and Food Sanitarians, and United States National Committee of International Dairy Federation.

Barbano earned a B.S. in Biology/Food Science in 1970, an M.S. in Food Science in 1973, and a Ph.D. in Food Science in 1978 from Cornell University (Ithaca, New York, USA).