The Incidence of Antibiotics, Sulfa Drugs and Quaternary Ammonium Compounds in the Fluid Milk Supply of New York State

Abstract

Summary An analysis of 1,794 samples of fresh blended pasteurized milks obtained throughout New York State during the early spring and late summer months indicated the presence of about 7 per cent inhibitory milks of varying degree of intensity. Approximately 1 per cent were strongly inhibitory toward commercial lactic starter. Antibiotics in these milks were indicated in relatively few cases and, where present, the amounts generally were between 0.05 and 0.1 unit per milliliter of milk. It was apparent from the results at the time this study was made that the incidence of inhibitory milks or antibiotics milks was not high enough to create any grave general problem for the New York dairy industry insofar as fermented dairy products are concerned. However, the few instances where antibiotics were found in significant quantities would create a serious individual problem for the manufacturer of fermented dairy products. No sulfa drugs were found in 922 samples of milk tested specifically for this chemical. Quaternary ammonium compounds were indicated in about 4 per cent of 832 milks analyzed and in most of these positive cases they existed from a trace to 3 ppm. Milks containing this compound apparently did not show on the average any greater inhibitory properties. Milks obtained during the hot summer months showed a significantly smaller incidence of inhibitory samples than milks obtained during the early spring months.