Rapid detection of ricin in cosmetics and elimination of artifacts associated with wheat lectin

Ricin can be detected in cosmetics at 0.005 µg/mL in the analytical sample using lateral flow devices (LFDs). Wheat germ, an ingredient used in skin care products is also a potential source of wheat lectin. False positives were observed when wheat lectin was added to LFDs from two manufacturers, irrespective of whether the LFD was specific for ricin, Staphylococcus enterotoxin B (SEB), or botulinum toxin. In contrast, pea and peanut lectins did not cause false positives. Substitution of the buffer supplied with the LFDs with a buffer containing 2.5% non-fat milk powder eliminated the occurrence of false positives. This substitution increased the LOD to 0.01 µg/mL ricin, which is an acceptable level for screening cosmetics for contamination by ricin.