Biomaterial Database

Microbiological plate and turbidimetric assays of chlortetracycline in feeds: collaborative study. 1977

H S Ragheb

The manual and automated turbidimetric assays and a modified official plate assay for chlortetracycline (CTC-HCl) in feed were collaboratively studied. Three feed samples (swine feed, 100 g CTC-HCl/ton; premix I, 20 g each of CTC-HCl and sulfamethazine/lb, and 10 g penicillin/lb; and premix II, 50 g CTC-HCl/lb) were analyzed at 2 dilutions. Twelve laboratories conducted the plate assay; 8 laboratories the manual turbidimetric method; and 7 laboratories, the Autoturb analysis. Within a method, there was no significant difference between dilutions. Between methods, there was a significant difference between the manual turbidimetric plate assays only for swine feed. However, the same sample dilutions or the average values of the 2 dilutions for both methods showed no statistical difference. Among the collaborators, the slope of CTC-HCl standard curve varied between about 2.0 and 3.0 for the plate method. The turbidimetric assay has been adopted as official first action for feeds containing larger than or equal to 20 g CTC-HCl/lb.

UI	MeSH Term	Description	Entries
D008722	Methods	A series of steps taken in order to conduct research.	Techniques,Methodological Studies,Methodological Study,Procedures,Studies, Methodological,Study, Methodological,Method,Procedure,Technique
D009391	Nephelometry and Turbidimetry	Chemical analysis based on the phenomenon whereby light, passing through a medium with dispersed particles of a different refractive index from that of the medium, is attenuated in intensity by scattering. In turbidimetry, the intensity of light transmitted through the medium, the unscattered light, is measured. In nephelometry, the intensity of the scattered light is measured, usually, but not necessarily, at right angles to the incident light beam.	Turbidimetry,Nephelometry,Turbidimetry and Nephelometry
D002751	Chlortetracycline	A TETRACYCLINE with a 7-chloro substitution.	Aureocyclin,Aureomycin,Aureomycine,Biomycin,Chlorotetracycline,Chlortetracycline Bisulfate,Chlortetracycline Hydrochloride,Chlortetracycline Monohydrochloride,Chlortetracycline Sulfate (1:1),Chlortetracycline Sulfate (2:1),Chlortetracycline, 4-Epimer,Chlortetracycline, Calcium Salt,4-Epimer Chlortetracycline,Bisulfate, Chlortetracycline,Calcium Salt Chlortetracycline,Chlortetracycline, 4 Epimer,Hydrochloride, Chlortetracycline,Monohydrochloride, Chlortetracycline,Salt Chlortetracycline, Calcium
D000821	Animal Feed	Foodstuff used especially for domestic and laboratory animals, or livestock.	Fodder,Animal Feeds,Feed, Animal,Feeds, Animal,Fodders
D001431	Bacteriological Techniques	Techniques used in studying bacteria.	Bacteriologic Technic,Bacteriologic Technics,Bacteriologic Techniques,Bacteriological Technique,Technic, Bacteriological,Technics, Bacteriological,Technique, Bacteriological,Techniques, Bacteriological,Bacteriologic Technique,Bacteriological Technic,Bacteriological Technics,Technic, Bacteriologic,Technics, Bacteriologic,Technique, Bacteriologic,Techniques, Bacteriologic