DEVELOPMENT OF A RAPID DIPSTICK IMMUNOASSAY FOR THE DETECTION OF PEANUT CONTAMINATION OF FOOD

Polyclonal antisera were raised to conarachin, the 7S globulin of pean ut, Arachis hypogea. The antisera were of high titre and were specific for conarachin, showing no significant cross-reaction with proteins f rom a range of nuts and legumes, as determined by immunoblotting and E LISA. A dipstick ELISA was developed using these antisera as both the capture and detector elements of the assay. The final steps utilized a n avidin-biotin detection system and tetramethylbenzidine as the subst rate. The dipstick assay was highly sensitive, and employed a simple o ne-step extraction method. It was able to detect as little as 0.01% (w /w) of peanut in marzipan and 0.1% (w/w) of peanut in chocolate. Roast ed nuts were also detected, down to a concentration of 0.1% (w/w) in b oth foods. The dipstick assay also functioned with a range of foodstuf fs, and readily indicated any that contained peanut. This method enabl es analysts to test, for the first time, for the presence of peanuts i n food in a fast and easy-to-use manner. The availability of such tech nology makes the task of monitoring foods for contamination by peanuts readily achievable, providing the industry with an important tool for quality control of raw materials, processes and products. Increased t esting will give consumers, particularly those sensitive to this poten t allergen, increased assurance as to the safety of the food they eat.