Detection of β-lactamase residues in milk by sandwich ELISA.

β-Lactamase residues in milk represent a public health risk. The cylinder plate detection method, which is based on bacterial growth, is laborious and time consuming. In this study, 15 monoclonal antibodies (mAbs) were selected against Temoneira (TEM) 1 β-lactamase. A sandwich enzyme-linked immunosorbent assay (ELISA) based on an optimum mAb pair was developed and validated for the detection of β-lactamase. The limit of detection and linear dynamic range of the method were 4.17 ng/mL and 5.5-100 ng/mL, respectively. β-Lactamase recovery in pure milk was 96.82-103.13%. The intra- and inter-assay coefficients of variation were 6.21-7.38% and 12.96-13.74%, respectively. Our developed sandwich ELISA can be used as a rapid detection method of β-lactamase in milk.