Microtrol discs are 1st generation derivatives from the
original freeze dried vial of the ATCC, NCTC, NCYC or CIP culture providing a
quick and reliable source of control micro-organisms of known reaction. They are
freeze dried, watersoluble discs that are offered in pack sizes of 10 or 25 per
vial depending on the strain. The viability of the organisms is stabilised by
the incorporation of activated charcoal in the disc and silicagel within the
vials.