Abstract
PREMISE: This study capitalized on a library of single-nucleotide polymorphisms created via whole genome sequencing (WGS) to develop and test a PCR assay for detecting toxic Digitalis species in food products. Complex foods can be difficult to analyze, but safeguarding consumer well-being and public health necessitates that products regulated by the U.S. Food and Drug Administration are contaminant free. METHODS: Ten pairs of PCR primers were designed, optimized, and tested against a subset of vouchered specimens. Two primer sets were screened using 55 vouchered Plantaginaceae species, complex food matrices, five different plant tissues, a dilution series, and spiked food products with 0.5%, 1%, and 5% biomass of D. purpurea and D. lanata. RESULTS: At optimized annealing temperatures, these primers amplified only Digitalis spp. (5). Both primer sets could detect spikes of D. purpurea and D. lanata down to 0.5% biomass and across three orders of magnitude, as well as five tissue types of D. purpurea. DISCUSSION: This study provides an enhanced DNA-based method for detecting Digitalis in complex food products. This novel method of primer development from WGS data lays the groundwork for a larger, more comprehensive panel for the rapid identification of botanical contaminants that may pose risks to consumers.