Description
The eggs used are from a farm where no antibiotic has been used for at least 28 days. They are collected from the morning run and are fully processed into final form in less than 12 hours from collection.
Egg Yolk indicates both lipase and lecithinase reactions of bacteria. On solid media containing egg yolk, lipolysis is shown by the formation of a thin, iridescent ‘pearly layer’ overlying the colonies and a ‘confined’ opalescence in the medium underlying them, seen best when the colonies are scraped off. Copper sulphate can be used to form a bright greenish blue insoluble copper soap with the fatty acids in both the pearly layer and the opalescent zone in the medium. Lecithinase activity is shown by wide zones of opalescence around the colonies, more intense and larger than the zones caused by lipolysis
