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Title: DETECTION OF INSECT FRAGMENTS IN WHEAT FLOUR BY DIFFUSE REFLECTANCE NEAR-INFRARED SPECTROSCOPY

Author
item Perez Mendoza, Joel
item Throne, James
item Dowell, Floyd
item Baker, James

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2002
Publication Date: 2/15/2003
Citation: PEREZ MENDOZA,J., THRONE,J.E., DOWELL,F.E., BAKER,J.E. 2003. DETECTION OF INSECT FRAGMENTS IN WHEAT FLOUR BY DIFFUSE REFLECTANCE NEAR-INFRARED SPECTROSCOPY, JOURNAL OF STORED PRODUCTS RESEARCH 39: 305-312.

Interpretive Summary: The presence of insect fragments in commercial wheat flour is a major concern to the milling industry because the U.S. Food and Drug Administration (FDA) has established a defect action level of 75 insect fragments per 50 g of flour. The current methods for detecting fragments in flour are expensive and time consuming. Thus, we tested a rapid, near- infrared spectroscopy (NIRS) method for detecting insect fragments in wheat flour, and compared the sensitivity and accuracy of the NIRS method with that of the current standard flotation method. Both techniques were able to detect the presence of fragments in flour samples. However, the flotation method was more sensitive at the FDA defect action level than the NIRS method. NIRS can classify flour samples containing less than 130 and more than 130 fragments with more than 80% accuracy. Although current NIRS instruments are unable to detect insect fragments at the FDA action level, this method should be reexamined in the future because NIRS technology is rapidly improving.

Technical Abstract: Insect fragments in commercial wheat flour are a major concern to the milling industry because consumers expect high quality and wholesome products at the retail level. The U.S. Food and Drug Administration (FDA) has established a defect action level of 75 insect fragments per 50 g of flour. Millers routinely test their wheat flour to comply with this federal requirement and to deliver sound flour to their consumers. The current standard flotation method for detecting fragments in flour is expensive and labor intensive. Therefore, we examined the possible use of a rapid, near-infrared spectroscopy (NIRS) method for detecting insect fragments in wheat flour. We also compared the sensitivity and accuracy of the NIRS method with that of the current standard flotation method. Fragment counts with both techniques significantly correlated with the actual number of fragments present in flour samples. However, the flotation method was more sensitive at the FDA defect action level than the NIRS method. We were unable to correctly classify samples as containing fewer than 75 fragments with our NIRS instrumentation. However, NIRS can classify flour samples containing more than 75 fragments, with more than 90% accuracy. Although current NIRS instruments are unable to detect insect fragments at the FDA action level, this method should be reexamined in the future because NIRS technology is rapidly improving.