The broad availability of plant-derived peptones and media
provides researchers and manufacturers with alternatives to
animal-based microbiological media. We have compared two
representative formulations that are marketed as substitutes for
the common maintenance medium, tryptic soy. Both formulations
supported the growth of a diverse list of test microorganisms,
maintained phenotypic traits relevant to their identity and
supported cryopreservation of the microorganisms. The results
of our study indicate that limited serial passage of cultures in
vegetable-based media does not cause selective pressures that
can lead to undesirable phenotypic changes resulting in culture
misidentification or failed quality control. Microbial production
of some biological material that requires complex media (i.e.
bioprocessing) or more specialized quality control activities,
particularly those involving fastidious microbes, may still
require additional media optimization and evaluation.