Erythromycin is an antibiotic produced by growth of certain strains ofStreptomyces erythreus. This product is composed largely of erythromycin A with small amounts of erythromycins B and C and is recommended for concentration at 100 mg/L. Concentrations between 50 and 200 mg/L have also proven effective in controlling bacterial growth. Erythromycin has been used as a motilin receptor agonist, to block respiratory glycoconjugate secretion in human airwaysin vitro,and for selecting plasmid-cured and recombinantlactococcus lactisMG1363 strains.