A novel real-time polymerase chain reaction method for the detection of pecan nuts in food.

摘要

A real-time PCR-based method for the detection of pecan nuts (Carya illinoiensis) in foods was developed. The method consists of DNA isolation by chaotropic solid phase extraction, followed by PCR with pecan-specific primers and a TaqMan fluorescent probe. The primers and the probe are targeted to the putative gene for the allergenic vicilin-like seed storage protein found in pecan nuts. The method was positive for 10 pecan varieties and negative for all other tested plant materials used in food industry, including walnuts. The intrinsic detection limit of the method was 1 pg pecan DNA which corresponds to 1.2 haploid genome copies. Using a series of model pastry samples with defined pecan contents, a practical detection limit of 0.01% (w/w) was estimated. Practical applicability of the PCR method was tested by the analysis of 13 food samples; no discrepancies between the declared and detected pecan contents were found. The presented PCR method is useful for sensitive and selective detection of pecans in food samples and can be performed in 1 working day.