HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Interpretive Summary Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Kaylegian, K. E. Articles by Barbano, D. M. Search for Related Content PubMed PubMed Citation Articles by Kaylegian, K. E. Articles by Barbano, D. M.

Modified Versus Producer Milk Calibration: Mid-Infrared Analyzer Performance Validation¹

K. E. Kaylegian^*, J. M. Lynch^*, G. E. Houghton, J. R. Fleming and D. M. Barbano^*,2

^* Northeast Dairy Foods Research Center, Department of Food Science, Cornell University, Ithaca, NY 14853
Kestrel Software Consulting, Berkshire, NY 13736
USDA, Agricultural Marketing Service, Texas Milk Marketing Area, P.O. Box 110939, Carrollton, TX 75011

² Corresponding author: dmb37{at}cornell.edu

Our objective was to determine the validation performance of mid-infrared (MIR) milk analyzers, using the traditional fixed-filter approach, when the instruments were calibrated with producer milk calibration samples vs. modified milk calibration samples. Ten MIR analyzers were calibrated using producer milk calibration sample sets, and 9 MIR milk analyzers were calibrated using modified milk sample sets. Three sets of 12 validation milk samples with all-laboratory mean chemistry reference values were tested during a 3-mo period. Calibration of MIR milk analyzers using modified milk increased the accuracy (i.e., better agreement with chemistry) and improved agreement between laboratories on validation milk samples compared with MIR analyzers calibrated with producer milk samples. Calibration of MIR analyzers using modified milk samples reduced overall mean Euclidian distance for all components for all 3 validation sets by at least 24% compared with MIR analyzers calibrated with producer milk sets. Calibration with modified milk sets reduced the average Euclidian distance from all-laboratory mean reference chemistry on validation samples by 40, 25, 36, and 27%, respectively for fat, anhydrous lactose, true protein, and total solids. Between-laboratory agreement was evaluated using reproducibility standard deviation (s_R). The number of single Grubbs statistical outliers in the validation data was much higher (53 vs. 7) for the instruments calibrated with producer milk than for instruments calibrated with modified milk sets. The s_R for instruments calibrated with producer milks (with statistical outliers removed) was similar to data collected in recent proficiency studies, whereas the s_R for instruments calibrated with modified milks was lower than those calibrated with producer milks by 46, 52, 61, and 55%, respectively for fat, anhydrous lactose, true protein, and total solids.

Key Words: infrared milk analysis • validation • calibration

This article has been cited by other articles:

				K. E. Kaylegian, J. M. Lynch, J. R. Fleming, and D. M. Barbano Lipolysis and Proteolysis of Modified and Producer Milks Used for Calibration of Mid-Infrared Milk Analyzers J Dairy Sci, February 1, 2007; 90(2): 602 - 615. [Abstract] [Full Text] [PDF]