β-lactam antibiotics are extensively used in milk production process. β-lactam antibiotics are a class of antibiotic agents containing a β-lactam ring, including penicillin derivatives, cephalosporins, monobactams, and carbapenems. β-lactam antibiotics are usually applied in treating bovine mastitis and other bacterial infectious diseases.

Drug residues test of β-lactam antibiotics applies the principle of competition-inhibition immunochromatography. β-lactam antibiotics in the sample bind to specific monocolonal antibodies labeled by colloidal gold, which prevent antibodies from binding to haptens immobilized on test line. Therefore, uncolored test line indicates a positive result.