Simultaneous detection of various contaminants in milk based on visualized microarray

Abstract Melamine, cephalexin and Aflatoxin M1 are three typical harmful compounds in dairy products, representing illegal additives, residual antibiotics and internal biological toxins respectively. In order to ensure the safety of dairy products, a rapid method is needed to screen and detect these various harmful substances. This work proposed a multiplexed detection technology for testing melamine, cephalexin and Alfatoxin M1 in milk simultaneously. The method involves the visualized microarray technology using 96-well microtitre plate. Multi-target molecules could be detected simultaneously through the competitive immune analysis. Compared to detection methods based on fluorescence or chemoluminescence, the colorimetric technology provides more direct result that can be detected using a commercial scanner. The limit of detection (LoD) was defined at 16.31 ng mL −1 , 8.21 ng mL −1 and 0.21 ng mL −1 for melamine, cephalexin and Aflatoxin M1 respectively, which all fit the national standards for maximum residue limits. The accuracy of method was adequate for these three substances. Experiments were also conducted using actual samples; the recovery rates found in the repeatability conditions were 103.1%–106.2% for melamine, 96.6%–98.3% for cephalexin and 105.4%–109.3% for Aflatoxin M1. This technology could achieve the simultaneous detection of various harmful substances and will have broad applications in the food safety analysis field.