TaqMan real-time PCR assay for detection of traces of Brazil nut (Bertholletia excelsa) in food products

Abstract

Mislabeling of food products containing Brazil nut may represent a serious thread for allergic consumers. In order to protect sensitized individuals, reliable methods to detect trace amounts of Brazil nut must be accessible to food industry as well as Food Safety authorities. According to this, a TaqMan real-time polymerase chain reaction (PCR) method has been developed for specific detection of Brazil nut in foodstuffs. The method employs Brazil nut specific primers and probe, targeting 2S albumin gene (Ber e 1), and a positive amplification control based on 18S rRNA gene. Results obtained on sensitivity with wheat flour spiked with different concentrations of raw and heat treated Brazil nut showed that the limit of detection (LOD) for the technique was 2.5 mg/kg. Applicability of the Brazil nut specific system was assessed through analysis of 66 different commercial food samples. The reported real-time PCR assay provides a useful tool for detection of Brazil nut DNA, and it can be used as a routine analysis to assert accuracy on food labeling.