Strains that are absolutely aconidial may be impossible to lyophilize, though most can be preserved on silica gel. For these stocks, preservation over liquid nitrogen is the backup storage form. These stocks can be sampled by scraping small pieces off the top with a flamed loop or needle. After being processed by any method, each strain is checked for its genetic characteristics. Silica gels are tested after a week, lyophils when the samples have dried.
Nutritional markers are scored, mating type is determined, unusual morphology is noted.
Wild collected strains are crossed to testers for the respective species to verify both species and mating type. Aberration stocks are crossed to standard wild types to observe expected ascospore patterns. The need to make such tests points out the need for persons depositing strains to be complete in describing traits of each strain.