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Analysis of Cashew Allergen in Shared Use of Frying Oil

Shimin Chen, University of Nebraska - Lincoln


Cashew is one of the major allergenic foods in the United States, accounting for approximately 15-30% of tree nut allergies. Nut oil-roasting is a process in which peanuts, cashew, and other types of tree nuts are submerged and roasted in a heated oil bath (120 – 200 °C). Cashew allergen may be transferred to other products through the shared use of frying oil, which may pose risk to allergic individuals. The objectives of this study were to use mass spectrometry (MS) to study the effects of oil-roasting on cashew proteins, to evaluate cashew allergen cross-contact in frying oil, to identify effective allergen removal methods, and to understand the potential risks. A customized protein database for cashew was developed to facilitate the identification of cashew protein using discovery MS analysis and the development of a targeted MS method. Seven additional protein sequences were identified for the three major cashew allergenic proteins. The change in cashew protein abundance upon different oil-roasting temperature and time were studied. A targeted quantitative MS method for cashew was developed using peptides that have high heat stability and sensitivity. Using the developed MS method, the amount of cashew protein transferred to oil and subsequent products via shared use of frying oil was analyzed. After frying 1.5 kg of cashew nuts in 1 L oil, 70-130 ppm total cashew protein (TCP) was transferred to oil, and about 20 ppm TCP was transferred to peanuts fried subsequently. A number of gravity-based and filtration-based cleaning methods were analyzed for their effectiveness in removing cashew allergens in oil. Three filtration methods (filters that retain particulates with size greater than 25 µm) were identified as the most effective ones, capable of reducing allergen content from more than 200 ppm TCP to less than 10 ppm. Risk assessments using a deterministic approach showed relatively low risk for cashew allergen cross-contact with peanut products. The findings in this study may contribute to the overall understanding of allergen cross-contact in shared frying oil.

Subject Area

Food Science

Recommended Citation

Chen, Shimin, "Analysis of Cashew Allergen in Shared Use of Frying Oil" (2022). ETD collection for University of Nebraska - Lincoln. AAI29165782.