Frequently Asked Questions (FAQ)

  • How should unopened ampoules be stored?

    Freeze-dried ampoules are stored at 10°C in the dark in the DSMZ. According to our Terms & Conditions, the material is to be used immediately upon receipt and the DSMZ can only accept claims for products where tests for viability have been made immediately after receipt. The DSMZ accepts no responsibility for the viability of material stored for extensive periods of time outside of the DSMZ.

    Where possible the DSMZ ships strains of microorganisms that have been dried under vacuum. While the DSMZ uses the generic term "freeze-dried" the actual methods may deviate slightly. Strains shipped as "freeze-dried" vials are usually stable when shipped without cooling or in dry ice. Consequently, normal postal services may be used provided that the biological material being shipped is packaged according to the postal regulations covering their shipment. Excessive temperatures should be avoided.

  • How long is the viability of cells in opened ampoules?

    The complete content of an opened ampoule has to be resuspended immediately in the appropriate medium given in the strain entry on our website, otherwise the cells will die rapidly.

  • What are the storage conditions of actively growing cultures?

    Actively growing cultures have to be subcultured under the correct conditions immediately after receipt. Psychrophilic and mesophilic microorganisms should usually be kept in the refrigerator before they are used unless otherwise stated. Especially sensitive, hyperthermophilic or obligately acidophilic strains should be kept at room temperature until used.

  • How are subcultures of a strain obtained from the DSMZ best prepared?

    Please, follow all instructions on the flyer accompanying your cultures consignment ”Important Information for the Recipient of Microorganisms regarding the re-activation of freeze dried strains. This information is also available on our website at: Opening of Ampoules and Rehydration of Dried Cultures.

    We also provide video tutorials for handling aerobes and anaerobes.

    Additional information on a variety of other organisms including myxobacteria, streptococci, enterococci, methanogens, acidophiles etc. can be found under Culture-Technology:

    Actively growing cultures are best sub-cultured using the medium and growth conditions listed on our website under the strain specific information. See our FAQ “Which growth conditions are recommended by the DSMZ for a particular strain?”


  • What is the expiry date of freeze-dried cultures in unopened ampoules?

    The DSMZ does not set an expiry date on freeze-dried cultures. Our Terms and Conditions state that all cultures are meant for immediate use only, indicating a warranty period of four weeks. Most freeze-dried strains can be stored for a much longer period, especially when kept under optimal conditions. However, the DSMZ will not certify a fixed date after which ampoules have to be discarded.

  • We wish to store a strain we obtained from the DSMZ, what methods should we use?

    Once strains obtained from the DSMZ have been sub-cultured in a customer’s laboratory the methods used for long-term storage are best investigated in the customer’s laboratory. Since the DSMZ holds more than 20,000 strain it is impossible to give exact details for each strain. However, the DSMZ generally stores the majority of its Bacteria and Archaea in liquid nitrogen and/or freeze dried. Some strains are also stored at -80°C. The methods used in the DSMZ and in other collections for long-term storage of Bacteria and Archaea have been published in the book:

    Day, J.G. & Stacey, G.N. (2007). Cryopreservation and Freeze-Drying Protocols. Methods in Molecular Biology Volume 368 2007 ( in the chapter Vacuum-Drying and Cryopreservation of Prokaryotes (