Determination of storage conditions for shrimp extracts: analysis of specific IgE-allergen profiles

The consumption of shrimp is a common cause of food hypersensitivity reactions. Shrimp allergy is diagnosed using a skin prick test (SPT) as well as by food challenges. Due to the lack of a wide variety of commercial shrimp extracts for SPTs, we selected various shrimp species for the preparation of local shrimp extracts. However, optimal storage conditions for the shrimp extracts which also maintains allergenic potency has not yet been identified. The objective of the present study was to determine the potency of the shrimp extracts under different storage conditions and durations. Specific IgE-allergen profiles of eight shrimp-allergic patients were investigated by using sera incubated with extracts prepared from lyophilized raw or boiled shrimp, which were stored at 4 degress C or -20 degress C for up to 4 weeks. When stored at -20 degress C, most allergens were preserved after 4 weeks. However, storage at 4 degress C results in few allergens remaining after 2 weeks. Boiled-shrimp extracts stored at 4 degree C and -20 degress C contained higher amounts of IgE-allergen complexes than raw-shrimp extracts. Moreover, in both raw and boiled shrimp extracts, the IgE bound 36-40 kDa allergens constituted the major proteins since they were observed in all IgE-allergen profiles. In conclusion, we recommend that shrimp extracts are stored at -20 degress C for 4 weeks to prevent the loss of allergens.