ARS | Publication request: Molecular Approaches for the Identification of Toxin in Foods

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: February 23, 2007
Publication Date: N/A

Technical Abstract: Due to the potential for intentional contamination of food with crude preparations containing ricin, a real-time PCR method was developed for detection of castor plant material in ground beef, milk and liquid eggs. One primer pair was identified and confirmed to be castor-specific and efficient for amplification of ricin gene in DNA extracts from castor, beef, milk and egg matrices. Of three different DNA extraction protocols compared, the hexadecyltrimethylammonium bromide (CTAB) method yielded the highest quality of DNA for real-time PCR assay. The detection limits for castor contamination were < 0.0001% in ground beef, < 0.00001% in milk and liquid egg (corresponding to 0.05 ug of ricin/g of beef and 5 ng of ricin/ml of milk or egg), these levels are well below the threshold for human oral toxicity. This real-time PCR method could be used as a fast and accurate alternate detection method for intentional castor contamination of food matrices.