ARS | Publication request: Detection of ricin contamination in ground beef by electrochemiluminescence immunosorbent assay

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 31, 2011
Publication Date: April 4, 2011
Citation: Brandon, D.L. 2011. Detection of ricin contamination in ground beef by electrochemiluminescence immunosorbent assay. Toxins. 3(4):398-408.

Interpretive Summary: Castor beans are an important agricultural crop, used to make castor oil, an industrial lubricant. Ricin is a highly toxic protein in castor beans, which remains in the solids after oil is extracted. Ricin has been used for intentional poisoning, and there is a need for methods to detect ricin in food to ensure a safe food supply. We developed antibodies that bind tightly and specifically to ricin. In this paper we describe the use of an advanced technology to detect this binding in ground beef that was experimentally spiked with tiny amounts of ricin. The detection method, known as electrochemiluminescence, uses a weak electric current to produce a chemical reaction that leads to generation of light. The amount of light we measured was directly related to the amount of ricin in the sample. Our ricin test was able to detect very small amounts of the toxin – less than the amount that would make a person sick if it was consumed in a serving of food. This means our test can be used for screening foods to detect and help prevent intentional poisoning.

Technical Abstract: Ricin is a highly toxic protein present in the seeds of Ricinus communis (castor), grown principally as a source of high quality industrial lubricant and as an ornamental. Because ricin has been used for intentional poisoning in the past and could be used to contaminate food, there is a need for analytical methodology to detect ricin in food matrices. We developed a monoclonal antibody-based method for detecting and quantifying ricin in ground beef, a complex, fatty matrix. The limit of detection was 0.5 ng/g for the electrochemiluminescence (ECL) method and 1.5 ng/g for enzyme-linked immunosorbent assay (ELISA). The detection of nanogram per gram quantities of ricin spiked into retail samples of ground beef provides approximately 10,000-fold greater sensitivity than required to detect a toxic dose of ricin (>1 mg) in a 100 g sample.