FACTORS AFFECTING THE VISUAL METHOD OF DETECTING ANTIBIOTICS IN MILK1

A green turquoise dye mixed with several antibiotics and used in intramammary infusions seems to provide a satisfactory marker for the visual detection of antibiotics in milk. The dye appeared in milk, coloring it green or turquoise, for approximately the same length of time as did penicillin, aureomycin, terramycin, or polymyxin, but slightly longer than did streptomycin. There was an inverse relationship between the milk yield of the animal and the number of milkings for which antibiotic and the dye appeared in milk. The age and the breed of the animal did not seem to affect the number of milkings for which antibiotic and the dye appeared in milk. During the storage of a mixture of the dye with antibiotics for 14 weeks, the dye exerted no appreciable detrimental effect upon the stability of the antibiotics. The dye does not seem to cause any apparent ill-effect upon the milk yield or the udder tissues of the animal. When the dye mixed with antibiotics was injected, the milk secreted following the inject...