• Patent

Detection of antibiotics in milk

A method for detecting the presence of antibiotics in milk whichcomprises the steps of: (a) contacting a solid matrix havingattached thereto a purified immobilized antibody with a volume ofmilk and an enzyme-labeled antibiotic, said antibody being specificto said antibiotic; (b) separating the matrix from the milk andrinsing the matrix with water to remove excess milk andenzyme-labeled antibiotic; (c) contacting the rinsed matrix with asubstrate, said substrate in the presence of said enzyme-labeledantibiotic exhibiting a color change the amount of which isquantitatively related to the amount of enzyme-labeled antibiotic;and (d) measuring the amount of antibiotic present in said milk bycomparing the color change in said substrate with a standard. Alsoprovided is a method for producing purified antibodies for use inthe foregoing detection method by: (a) convalently conjugating anantibiotic having a lactam-ring in the molecule to a proteincapable of binding thereto through said lactam-ring; (b) injectinginto a host animal capable of raising antibodies specific to saidantibiotic the conjugate obtained in step (a) so as to raise saidspecific antibodies; (c) covalently conjugating the same antibioticin step (a) to a second protein capable of binding thereto throughsaid lactam-ring and different than the protein used in step (a) toform a second conjugate; (d) covalently binding said secondconjugate to a solid matrix to form an affinity matrix forpurifying the antibodies; (e) isolating and purifying the specificantibodies raised in step (b) by contacting the host animal serumwith the affinity matrix; and (f) recovering the specificantibodies in pure form.


Brown, R. J., & Swaisgood, H. E. (1982). IPC No. U.S.Detection of antibiotics in milk (Patent No. 4347312.)