Detection of pea in food by real-time polymerase chain reaction (PCR)

Development and Evaluation of a Real-Time PCR Multiplex Assay for the Detection of Allergenic Peanut Using Chloroplast DNA Markers

Peanut is one of the most commonly consumed allergy-causing foods in the United States. Prevention of accidental consumption by allergic individuals is assisted by methods that effectively identify the presence of peanut in food, even at trace levels. This study presents a multiplex real-time polymerase chain reaction (PCR) assay that uses chloroplast markers ( matK, rpl16, and trnH-psbA) to specifically detect peanut in three types of foods: baked goods, chocolate, and tomato sauces. Food matrices were spiked with raw peanut at concentrations ranging from 0.1 to 10⁵ ppm. The assay was evaluated with respect to linear range and reaction efficiency. High reaction efficiencies were generally obtained across 6-7 orders of magnitude. Limits of detection were between 0.1 and 1 ppm, and reaction efficiencies were mostly within the preferred range of 100 ± 10%. Our results indicate that real-time PCR assays using chloroplast markers can be a valuable tool for peanut detection.

Pea detection in food and feed samples by a real-time PCR method based on a specific legumin gene that allows diversity analysis

Real-time polymerase chain reaction is currently being used for the identification and quantification of plant and animal species as well as microorganisms in food or feed samples based on the amplification of specific sequences of low copy genes. We report here the development of a new real-time PCR method for the detection and quantification of the pea (Pisum sativum) based on the amplification of a specific region of the legS gene. The specificity was evaluated in a wide range of plant species (51 varieties of Pisum sp., and 32 other plant species and varieties taxonomically related or nonrelated). The method allows the detection and quantification of as low as 21.6 pg of DNA, which corresponds to 5 haploid genome copies. The system has been shown to be sensitive, reproducible and 100% specific for the rapid detection and quantification of pea DNA in processed food and feed samples, being therefore suitable for high-throughput analysis.