Identification of hidden allergens: detection of pistachio traces in mortadella.

An analytical method based on the detection of specific DNA was developed and applied to mortadella samples with and without pistachio (Pistacia vera). The method is proposed for the detection of traces of pistachio deriving from previous processes or from accidental contamination, since in predisposed individuals pistachios can cause allergic reactions leading to anaphylactic shock. Three pairs of primers were identified and tested by polymerase chain reaction (PCR) on mortadella samples prepared with pistachio. Accidental contamination was also simulated. The optimized PCR was able to detect the presence of pistachio, even at low concentrations. The primers pair PSTC 1-2 is suggested for unambiguous identification of pistachio in mortadella. The limit of detection for this primers pair was 100 mg kg-1. No interference was observed from other spices or ingredients utilized in the formulation of the mortadella. The method enabled the identification of possible traces of pistachio remaining in the production plant after less than thorough washing.