Submitted to: Food and Agricultural Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/10/2011
Publication Date: 4/1/2012
Publication URL: http://handle.nal.usda.gov/10113/55904
Citation: Brandon, D.L. 2012. Electrochemiluminescence immunosorbent assay of ricin in ground beef: Biotinylated capture antibodies and matrix effects. Food and Agricultural Immunology. 23(4):329-337. Interpretive Summary: Ricin is a highly toxic protein found in castor beans, including the byproducts resulting from the industrial production of castor oil. Because ricin has been used for intentional poisoning there is a need for methods to detect ricin in food to assure a safe food supply. We developed antibodies that bind ricin, and then explored a detection system known as electrochemiluminescence. The method was sensitive and specific for both qualitative and quantitative detection of ricin intentionally added to ground beef.
Technical Abstract: Ricin is a highly toxic protein present in the seeds of castor (Ricinus communis), grown principally as a source of high quality industrial lubricant and as an ornamental. Because of the past use of ricin for intentional poisoning, there is a need for analytical methodology to detect ricin in food matrices. Ground beef and other fatty, solid matrices present challenges for extraction and detection of protein constituents. This study focused on the use of streptavidin-coated assay plates, with biotinylated mAbs immobilized as capture reagents. It also explored the impact of matrix components on immunosorbent analyses of ricin in enzyme-linked and electrochemiluminescent detection systems. A variety of monoclonal antibody pairs enabled assays with predetermined specificity for ricin vs. the other castor agglutinin, RCA-1. The inclusion of 100 mM galactose in the extraction medium and assay of extracts at low dilution (for example 1:5), produced excellent quantification of ricin in the 1 – 20 ng/g range in ground beef.