Leifert & Waites medium has been specially formulated for in vitro detection of endogenous contaminants in plant cell, tissue and organ cultures. Ammonium nitrate and potassium nitrate serves as the sources of nitrate. Glycine serves as the source of amino acid. Glucose and sucrose serves as carbohydrate sources. Medium does not contain agar; hence this component has to be added to the medium before use.

This medium was developed to determine and identify potential pathogens in explants. Explants are placed in the medium for 1-2 weeks. The medium was developed to contain enough nutrients to support the maintenance of the explant but also contains nutrients required to support the growth of microorganisms present in or on the surface of the plant tissue.