Assessment of Peanut Allergen Cross-Contact Risk from Reused Roasting Oil Using a Targeted Proteomics Method

Allergen cross-contact risk can arise when the oil used to roast peanuts is reused. Heat-induced protein denaturation reduces the accuracy of immunochemical methods; therefore, the objective of this study was to develop a targeted proteomics method to measure peanut transfer to roasting oil. Marker peptides for quantification were identified from blanched peanut butter, and method-determined protein levels of peanut butter-spiked oil after 10 min heating at 190 °C ranged between 77% and 94% recovery. Whole peanuts were then batch-roasted in oil, and peanut protein levels were measured up to 405 μg of peanut protein/mL after 10 batches. Filtration trials of the batch-roasted oil revealed that metal sieves with a pore size of ≤25 μm and filter papers with a pore size of ≤35 μm reduced peanut protein concentrations below reporting limits. These results highlight the need for accurate quantitative methods when assessing the peanut allergen risk in thermally processed foods and determining the efficacy of preventive controls.