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A Method for the Assay of Penicillin in Animal Feeds

1952; SAGE Publishing; Volume: 81; Issue: 3 Linguagem: Inglês

10.3181/00379727-81-19978

1535-3702

Roberto Esposito, W. L. Williams,

Pesticide Residue Analysis and Safety

A rapid simplified technic utilizing inexpensive equipment has been developed for the determination of penicillin in feeds and feed supplements. The method is useful to determine the quantities of penicillin added to feeds for nutritional purposes since it can be used to assay accurately as little as 0.5 g of procaine penicillin per ton of feed. Feeds which are not supplemented with antibiotics do not give blank values. A sample of antibiotic-free feed of the same or similar composition as the samples to be assayed must be available. The test organism is S. aureus 209-P which is suspended in thin layers of agar medium upon which paper pads are placed containing methanol extracts of the feeds. The use of the paper pads to contain feed extracts and the use of Sulfasuxidine in the assay medium are the features of the method which permits the method to be used for the determination of the small amounts of penicillin added to feeds.