A Collaborative Study of the Delvotest-P Method to Detect Low Concentrations of Penicillin in Milk

During a collaborative study at a large number of milk-receiving stations from a dairy industry in the Netherlands, in which penicillin was added in various concentrations of 0, 4, 5, 6, 7, 8 and 10 IU/1 to milk samples, the Delvotest-P method gave reliable results in almost all instances. Of the 22 milk samples that were tested, both undiluted and dilluted 1:1, by up to 17 control stations in seven experiments, a total of 518 readings were obtained. There were no negative readings among the 249 samples that contained 4 or more IU penicillin per liter and only one doubtful reading among 186 samples that were free of penicillin. In some instances the test was found a little more sensitive than one might conclude from the instructions.