Abstract: The detecting method of tube diffusion was confirmed with PCA medium as testing medium, Bacillus stearothermophilus c953 as indicative bacteria and bromocresol purple as indicator. In this study, six kinds of β-lactam antibiotics were detected by the two methods of tube diffusion and 2,3,5-triphenyl tetrazolium chloride test. On the foundation of efficient parameters and actual experiment, it is indicated that the method of tube diffusion is economic, quick, convenient and stable,and the limit of detection measures up. So it is a good method for detecting β-lactam antibiotic residues in raw milk in China.

Key words: raw milk； &beta, -lactam antibiotics； detecting method； comparison；