May 20/Journal of Technology & Science -- According to recent research from Zaragoza, Spain, "Immunoassays are used to screen for the presence of genetically modified organisms in raw materials. However, processing may condition the usefulness of immunoassays to analyse genetically modified foods because it leads to protein denaturation that affects recognition by antibodies."

"We studied the effect of processing on the detection of Cry1A(b) protein in model foods prepared with transgenic maize using a sandwich ELISA. Nixtamalization at 100 A degrees C for five minutes and at 85 A degrees C for 60 minutes gave 40 and 70% loss of Cry1A(b) protein. In the preparation of porridge, the concentration of Cry1A(b) protein did not change until the mixture reached 75 A degrees C, but it decreased by 90% after three minutes at that temperature," wrote R. Deluis and colleagues, University of Zaragoza.

The researchers concluded, "Concentration of Cry1A(b) protein decreased by 90% in tortillas griddled at 180 A degrees C for 20 seconds, but no protein was detected in fried tortillas after 10 seconds at 190 A degrees C. Cry1A(b) protein is rapidly denatured by heat treatment resulting in a marked decline in concentration and decreased detection in processed foods."

Deluis and colleagues published their study in European Food Research and Technology ("Immunochemical Detection of Cry1A(B) Protein in Model Processed Foods Made with Transgenic Maize." European Food Research and Technology, 2009;229(1):15-19).

For additional information, contact M.D. Perez, University of Zaragoza, Faculty Vet., Miguel Servet 177, E-50013 Zaragoza, Spain.

From the May 26, 2009, Prepared Foods E-dition