This section contains the general quality control and quality assurance procedures that are utilized at Hardy Diagnostics.


Dehydrated media and other ingredients are performance tested by the manufacturers. Their quality control records are available to Hardy Diagnostics. Powdered media is obtained from several different sources, which offers the advantage of choosing the best product for each type of media. The powder bases are made by the following manufacturers: Hardy Diagnostics, Acumedia, BBL/Difco, and Oxoid. Powdered media manufactured by Hardy Diagnostics is tested against other manufacturers brands to ensure performance.

Petri dishes have been tested by the manufacturer for sterility and toxicity before distribution. The dishes are sterilized by gamma radiation. These records are kept on file, and are available to Hardy Diagnostics.

Animal blood is tested for hematocrit, hemolysis (osmotic fragility) and sterility. The sheep blood comes from a herd that is designated for bleeding purposes only for Hardy Diagnostics. The sheep are kept on a healthy diet, which is completely free from antimicrobics. The health of the sheep is continually monitored in accordance with a veterinary supervised program.

Blood derived from slaughterhouses is never used. Blood from this source can contain unwanted antimicrobics and is often prone to spontaneous hemolysis.

To ensure freshness, the sheep are bled every weekend and the blood containing media is produced on Tuesday, Wednesday, and Thursday of that same week.

Antimicrobics and supplements prepared by Hardy Diagnostics are tested for inhibition performance and sterility with each batch. Potency for each antimicrobic must fall within a specified range on the manufacturer's "Certificate of Analysis".

Deionized water used for culture media meets or exceeds CLSI Type II water specifications. Water filters and deionizer are continually monitored for purity using electrical resistance. Additional tests including bacterial counts and silicate determinations are performed to assure water quality.


Scales and balances are checked weekly and are cleaned regularly.

Plating and tube filling equipment are calibrated with each run; thoroughly cleaned, disinfected and checked for proper operation daily.

Pressure and temperature are recorded during each run and are verified to validated specification. All heating processes are validated statistically using thermocouples at multiple locations within the autoclaves or vessels verifying sterility assurance levels are achieved.

Incubators, refrigerators, and freezers are monitored regularly for proper temperatures. Incubators are controlled to maintain the required temperature, plus or minus one degree C. Refrigerator temperatures are controlled to 2-8 degrees C. Freezer temperatures are controlled < -8 degrees C.

pH Meters are cleaned and calibrated with appropriate buffers daily.

Water filters and deionizer are continually monitored for purity using electrical resistance. All water for media production is deionized and run through charcoal filters to remove any toxic chemicals. All filters and resin bed tanks are changed regularly, so that the electrical resistance does not drop below 10,000,000 Ohms (10 Megohms).

Glassware and vessels are cleaned after each use and rinsed thoroughly with deionized water.

HEPA (High Efficiency Particulate Air) filters and air quality are tested regularly in the environmentally controlled rooms by culturing for airborne contaminants and electronic counting of non-viable particles. Equipment surfaces are also cultured routinely. Airflow volume and positive pressure are routinely monitored.

Measuring devices are routinely calibrated against standards that are traceable to an NIST certified instrument. When such a standard is not available an in house standard that has at least a 4 to 1 accuracy ratio will be used.