Allergens in Food: Analytical LC-MS/MS Method for the Qualitative Detection of Pistacia vera

Pistachio (Pistacia vera) is widely consumed among tree nuts but capable of triggering severe IgE-mediated reactions in allergic individuals. Due to the similarity of cashew-borne and pistachio-borne allergen proteins and DNA, traditional detection methods, such as ELISA and PCR, often suffer from cross-reactivity, limiting their ability to discriminate between these two allergens. This study presents a sensitive LC-MS/MS method for the simultaneous detection of pistachio and cashew allergens in processed food with a screening detection limit (SDL) equal to 1 mg/kg. The method was validated for specificity, SDL, β error, precision, and ruggedness, and applied to various matrices (cereals, chocolate, sauces, and meat products). Ruggedness testing showed that all considered parameters must be carefully monitored by the operator, and sample preparation must be carried out without any modification in parameter values, under strictly controlled conditions. Good reproducibility was achieved for pistachio detection, while ongoing investigations should be carried out to overcome existing constraints for cashew. The LC-MS/MS method described in this work is a discriminatory method suitable for official food allergen control to selectively differentiate pistachio from cashew allergens, overcoming the limitations of PCR and ELISA when cross-reactivity occurs. It represents a validated tool for pistachio detection and a promising approach toward improving cashew allergen analysis.