Detection of Peanut Agglutinin in Chocolate and Cookies by Enzyme-Linked Immunosorbent Assay
T.Y. Yi, A.W. Smallwood, T.W. Brueggemeyer and R.D. Satzger, Forensic Chemistry Center, ORA, FDA, Cincinnati, OH 45237
Undeclared peanuts in foods often cause severe allergic reactions among sensitive individuals. In this report, peanut agglutinin (PNA) was used as a marker for peanuts in foods. An Enzyme-Linked Immunosorbent Assay (ELISA) was developed to determine the presence of PNA in chocolate and cookies. Affinity purified anti-peanut agglutinin (anti-PNA) and enzyme labeled anti-PNA were applied to 96-well microplates to capture and detect PNA. PNA was extracted from homogenized samples by phosphate buffered saline (PBS) and the extract was applied to the microplate for the ELISA. Control samples containing various nuts were analyzed as a check against false positives. The reported method reliably detected PNA at levels greater than 1 ng/ml. No false positive results were obtained at or above the detection level. A few samples showed possible cross reactivity with anti-PNA.