Abstract
The tetracycline galactosidase (TG) test, a new method for the detection of tetracycline residues in raw milk based on the inhibition of β-galactosidase biosynthesis in Escherichia coli, was previously validated with spiked milk samples. It has now been applied to milk from cows treated with oxytetracycline. In view of the occurrence of false positives, related to highly elevated somatic cell counts (>106/ml), the improved TG test was developed, in which a heating step (80°C, 15 min) preceded the original TG test protocol. A good agreement with other assays (Delvotest SP, the Bacillus cereus microtiter test, the LacTek tetracycline milk screening test, the Charm HVS-8100 tetracycline test) as well as with high-pressure liquid chromatography was obtained. No false negatives were observed with reference to the established maximum residue limit for tetracyclines of 100 μg/kg milk.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
