Determination of streptomycin residues in eggs and stability of residues after cooking.

An assay procedure for streptomycin was developed, using a surfactant-pH 8 buffer extraction, heating at 85 degrees C to eliminate inhibition from lysozyme activity, and centrifuging to remove physical barriers to diffusion. Recoveries of streptomycin from supplemented eggs averaged 42% over the range of 0.33--2.05 microgram streptomycin/g egg. Eggs were supplemented at 3.0, 30.0, and 300 microgram streptomycin/g and subjected to various cooking procedures: frying, poaching, scrambling, and hard boiling. There was little or no loss of activity as a result of the various cooking procedures with the exception of one of the hard boiled varieties where there was a 40% loss only at the 3.0 microgram/g supplementation. Streptomycin residues were quite stable to normal egg preparation procedures.