Anti‐ E. coli lmmunoglobulin Y Isolated from Egg Yolk of Immunized Chickens as a Potential Food Ingredient

Active immunoglobulin (IgY) was isolated from egg yolk of chickens immunized with formalin‐treated E. coli. The antibody activity was measured by enzyme‐linked immunosorbent assay using E. coli lipopolysaccharide as an antigen. The anti‐ E. coli IgY aggregated the bacterial cells and inhibited their growth in vitro. IgY was relatively heat‐stable without loss in antibody activity by pasteurization. IgY was stable at pH above 4, but was more susceptible to pepsin than bovine IgG, while appreciable activity was retained by IgY after trypsin‐ and chymotrypsin‐digestion. It appears possible, therefore, to use IgY for the fortification of food products, especially infant formulae.