Cryopreserve Beads Mix

Under aseptic conditions, prepare a thick suspension (to more than a 2 McFarland standard) of pure bacteria from young cultures (20-24 hours) in the vial.

Mix the vial to soak the beads with bacterial cells and remove the cryo-solution by aspirating it with a sterile pipette. When used as recommended, each vial will store 25 ± 5 beads, identical potential cultures.

Close the cryotube tightly; record and identify vials with permanent marker or with cold-resistant labels. Colours of caps and beads provide a system to be used to differentiate species.

Store the inoculated vials at -25 °C, -30 °C, -35 °C or up to -80 °C for best long term results.

To recover the organism, open a vial under aseptic conditions and, using a sterile needle or a sterile forceps, remove one bead. The inoculated bead may then be used to directly streak onto solid medium or to be dropped into an appropriate liquid medium.

The vial must be closed again as soon as possible and returned immediately to low temperature storage. Excessive changes in temperature reduce the viability of the microorganisms.

It can successfully preserve various species of Actinobacillus, Clostridium, Haemophilus, Neisseria, Pasteurella, Yersinia, Vibrio, and a good number of Enterobacteriaceae, Staphylococcus, Lactobacillus and Streptococcus.

Also used in moulds (Aspergillus as example) and yeast (Saccharomyces, Candida and others) with good performance, working from -30 °C, 4 years frozen.

In reference literature they point up to 10 years, working at lower temperatures, as -60 to -80 °C.

Please note that some fastidious microorganisms and specific fungi may be negatively affected by the freezing temperature. So, we recommend proceeding with specific tests for special strains.

Physical/chemical control

Microbiological control

Prepare a suspension from pure culture.

Pipette off the excess liquid after vortexing to coat the beads with microorganisms - 30 s.

Freeze at approx. -30 °C for 2 days.

Thaw - swab streaking - incubate for 24-48 h.

Sterility control

Incubation 48 hours at 30-35 °C and 48 hours at 20-25 °C: NO GROWTH.

Check at 7 days after incubation in same conditions.

• Murray, P.R. et al. 1995 Manual of Clinical Microbiology. 6th Ed. American Society for Microbiology. Washington DC.
• Chandler, D. Cryopreservation of fungal spores using porous beads, Mycol. Res. 98(5) 525-526 (1994).