Molecular fingerprinting of DNA proves to be the most reliable of all biological assays applied today in spite of an extensive application of other biomolecules as markers in different functional evaluation studies.Ricin, Castor toxin profiling is not an exception as researchers from USA have devised a protocol for the detection of ricin in food as an accidental or intentional contaminant on the basis of a DNA based molecular marker, unique to castor.The experimental result indicated a sensitivity of 5 microgram of toxin per unit gram of ground beef which is promising according to scientists. They claim further that their methodology’ sensitivity is well below the threshold oral toxicity levels of toxin.

Molecular marker are highly polymorphic and hence the fingerprint that they generate will display a minimum probability for  mismatch but requires a high technical skill.It also has a critical limitation that any insignificant contamination interfering with experimental template DNA  would readily produce a magnified artifact and lead to misinterpretations.

For further reading: http://www.ncbi.nlm.nih.gov/pubmed/17227091