Rationale: The use of cumin (Cuminum cyminum L) is widespread in modern cuisine. Recent reports of peanut contamination in cumin highlight the need for robust detection methods for trace amounts of allergenic protein in spices. This study aims to apply recently developed proteomic strategies and existing immunological methodologies to assess the risk posed to allergic consumers by traces of peanut in cumin.
Methods: Cumin samples were extracted under harsh denaturing conditions and protein composition determined by 1D-PAGE. Stable-isotope dilution multiple-reaction monitoring mass spectrometry (SID-MRM-MS) and commercial ELISA were employed to detect and quantify peanut presence in several batches of ground cumin. Serum samples from peanut allergic patients were obtained from the Manchester Respiratory and Allergy Biobank and IgE reactivity assessed using immunoblotting. An allergen risk assessment based on VITAL® (Voluntary Incidental Trace Allergen Labelling) was conducted to determine the potential hazard posed to allergic consumers.
Results: Ground cumin samples found to contain peanut protein by ELISA and mass spectrometry were used to assess IgE reactivity of peanut allergic patients. Detection levels were related to ED01% of 0.2mg peanut protein as specified by VITAL. Risk assessment indicated levels of peanut present would not pose a risk to peanut allergic individuals based on normal consumption amounts.
Conclusions: The complexities of spice components, such as phenolic compounds, can cause interference with protein analysis, but can be partially removed by de-fatting. Due to issues associated with cross reactivity when analysing spices a minimum of two detection methods can provide confidence in analytical methods used for allergen recalls.