Detection of cows' milk in ewes' milk and cheese by an indirect enzyme-linked immunosorbent assay (ELISA).
An indirect enzyme-linked immunosorbent assay was successfully developed for the detection of defined amounts of cows' milk (1-50%) in sheeps' milk and cheese. The assay used polyclonal antibodies raised in rabbits against bovine caseins (BC). The anti-BC antibodies were recovered from the crude antiserum by immunoadsorption and elution from a column containing BC. The antibodies were biotinylated and rendered cows' milk specific by mixing them with lyophilized ovine and caprine caseins. ExtrAvidin-peroxidase was used to detect the biotinylated anti-BC antibodies bound to BC immobilized on 96-well plates. Subsequent enzymic conversion of substrate gave clear absorbance differences when assaying mixtures of sheeps' milk and cheese containing variable amounts of cows' milk.
Rodríguez
E
E
Departamento de Higiene y Tecnología de los Alimentos, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
Martín
R
R
García
T
T
Hernández
P E
PE
Sanz
B
B
D000818:Animals; D000906:Antibodies / Q000276:immunology; D001667:Binding, Competitive; D001710:Biotin; D002364:Caseins / Q000276:immunology; D002417:Cattle; D002611:Cheese / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005506:Food Contamination / Q000032:analysis*; D008892:Milk / Q000032:analysis*; D012756:Sheep; D013045:Species Specificity
D000906:Antibodies; D002364:Caseins; D001710:Biotin