Peanut allergy can have serious reactions to trace of peanut allergens and often need extreme measures to avoid potential contact with these allergens.Therefore,it is necessary to develop a quick,accurate and sensitive method to detect the trace Ara h 2,the major peanut allergens,in foods.To develop a competitive inhibition ELISA for quantification of Ara h 2,a standard Ara h 2 allergen was derived from the purification of crude peanut proteins extract using anion-exchange chromatography,and a specific rabbit serum was raised against Ara h 2 from Japanese rabbits immunized with routine method.