title: Improved microbiological assay for penicillin residues in tissues and stability of residues under cooking procedures.
abstract: The microbiological assay for penicillin residues was improved by using centrifugation to remove physical barriers to diffusion, a small buffer/meat extraction ratio, and a more sensitive 2-layer assay system. Recoveries from muscle, kidney, and liver tissues ranged between 70.1 and 86.7% with measurable levels of 0.03--0.05 unit/g. By comparison, the Food and Drug-suggested methodology yielded recoveries of 45.9--54.0% and levels of detectability of 0.08--0.10 unit/g. Cooking of hamburger, steaks, and port chops indicated that procaine penicillin withstood cooking conditions, and significant levels of the original activity remained.
mesh_terms: D000818:Animals; D001681:Biological Assay; D002417:Cattle; D002645:Chickens; D004355:Drug Stability; D005504:Food Analysis / Q000379:methods; D006358:Hot Temperature; D008460:Meat / Q000032:analysis*; D010402:Penicillin G Procaine / Q000032:analysis*; D012505:Sarcina / Q000254:growth & development; D013552:Swine; D014018:Tissue Distribution
chemical_list: D010402:Penicillin G Procaine