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Pink and black salmonella typhimurium cells.

Microbiology Quality Control as Described in the Compendia

March 19, 2015, at 12:00 PM ET


The quality control microbiology lab serves a valuable function in the pharmaceutical manufacturing environment in terms of providing information on the biological quality of the products being produced. The major tests are familiar to us all: Microbial Limits, Sterility Tests, and Antimicrobial Effectiveness Tests. All of these tests require strict attention to detail for reproducible results, and the compendium also provides guidance on the quality control aspects of laboratory operations.


Scott Sutton, headshot.

Scott Sutton, PhD

Principal, Microbiology Network, Inc.

Liz Kerrigan, headshot.

Liz Kerrigan

Director, Business Development, Sales & Marketing, ATCC

Questions and Answers

Can a -70°C freezer be used to store ATCC Minis?

Yes, -70°C is an appropriate temperature to store ATCC Minis.

Can ATCC Minis be used to make in-house control stocks?

ATCC Minis put an end to do-it-yourself banking with each six-pack of ready-to-use quality controls strains in glycerol stock. This new product format is the same frozen format that you use in your own laboratory, so there is no need to make in-house control stocks. Just open, plate, and go!

Does ATCC have ATCC Minis that match my VITEK 2 cards?

Yes, ATCC plans on releasing strains later in the spring of 2015 in the ATCC Mini format that are aligned with VITEK 2 cards from bioMérieux.

Is there data to support phenotypic or genotypic changes after 5 passages?

We recommend no more than 5 transfers or passages be made from an ATCC Genuine Culture. Repeated passage or serial culture increases the risk of contamination and can result in undesirable genotypic and/or phenotypic changes. The recommendation of five passages or fewer from the ATCC reference culture is broadly accepted in the healthcare community and the pharmaceutical and biopharmaceutical industries. U.S. Pharmacopeia Chapter 51: Antimicrobial Effectiveness Testing. U.S. Pharmacopeia National Formulary, 2005 states: "The viable microorganisms used in the test must not be more than five passages removed from the original ATCC stock." ATCC agrees with this recommendation.

The ATCC website says to store ATCC Minis at -80°C. Can I store them at -20°C?

Our real-time testing has so far demonstrated that ATCC Minis are viable up to 2 months at -20°C. We plan on continuing this testing through 1 year to assess long-term viability at this temperature.

What are the applications of ATCC Minis?

ATCC Minis are ideal for quality control analyses. A number of our strains in the ATCC Minis format are the same quality control strains recommended for use in the United States Pharmacopeia, European Pharmacopeia, and Japanese Pharmacopeia. Further, our newest products include strains that have applications in food testing analyses.

What passage number are ATCC Minis?

ATCC Minis are at passage zero.

What percentage of glycerol is used for the ATCC Minis stocks?

ATCC uses 10% glycerol for our ATCC Minis.

I currently purchase preceptrols. Why are the ATCC minis more expensive?

With ATCC Minis, you are receiving 6 ready-to-use vials of a strain per order instead of one vial per order. This brings the unit price per vial to approximately $38, which is comparatively less expensive than the $60 per vial for each preceptrol. What’s more, because ATCC Minis are provided in a ready-to-use glycerol stock format, you can do away with the time and expense associated with strain propagation and preservation, and go straight to your research.