Specific detection of potentially allergenic peach and apple in foods using polymerase chain reaction

Two PCR methods were developed for specific detection of the trnS-trnG intergenic spacer region of Prunus persica (peach) and the internal transcribed spacer region of Malus domestica (apple). The peach PCR amplified a target-size product from the DNA of 6 P. persica cultivars including 2 nectarine and 1 flat peach cultivar, but not from those of 36 nontarget species including 6 Prunus and 5 other Rosaceae species. The apple PCR amplified a target-size product from the DNA of 5 M. domestica cultivars, but not from those of 41 nontarget species including 7 Maloideae and 9 other Rosaceae species. Both methods detected the target DNA from strawberry jam and cookies spiked with peach and apple at a level equivalent to about 10 μg of total soluble proteins of peach or apple per gram of incurred food. The specificity and sensitivity were considered to be sufficient for the detection of trace amounts of peach or apple contamination in processed foods.