Escherichia coli O157:H7, heated at 121C for 20 min or treated with Formalin, was injected into laying hens to prepare hyperimmune eggs. Chicken egg yolk antibody (IgY) raised against E. coli O157:H7 treated by heat or formalin was found in highly specific activity levels by ELISA. E. coli O157:H7-specific IgY extracted by ammonium sulfate precipitation and gel chromatography on Sephacryl S-300 of the egg yolk water-soluble fraction contained 15.5 mg/g of total IgY % in heat killed and 10.0 mg % in formalin killed of specific IgY. Anti-Heat killed IgY cross-reacted 55.3% with formalin killed E. coli. The cross-reactivity of anti-Formalin killed IgY with heat killed E. coli was 42.4%.
