Section 798. Microbiology testing: constant and consistent test conditions

A. Laboratory facilities. Floors and work surfaces shall be nonabsorbent and easy to clean and disinfect. Work surfaces shall be adequately sealed. Laboratories shall provide sufficient storage space, and shall be clean and free from dust accumulation. Plants, food, and drink shall be prohibited from the laboratory work area.

B. Laboratory equipment.

1. Temperature measuring devices. Temperature measuring devices such as liquid-in-glass thermometers, thermocouples, and platinum resistance thermometers used in incubators, autoclaves and other equipment shall be the appropriate quality to meet specifications in the test method. The graduation of the temperature measuring devices shall be appropriate for the required accuracy of measurement and they shall be calibrated to national or international standards for temperature (see 1VAC30-45-740 C). Calibration shall be done at least annually.

2. Autoclaves.

a. The performance of each autoclave shall be initially evaluated by establishing its functional properties and performance, for example, heat distribution characteristics with respect to typical uses. Autoclaves shall meet specified temperature tolerances. Pressure cookers shall not be used for sterilization of growth media.

b. Demonstration of sterilization temperature shall be provided by use of continuous temperature recording device or by use of a maximum registering thermometer with every cycle. Appropriate biological indicators shall be used once per month to determine effective sterilization. Temperature sensitive tape shall be used with the contents of each autoclave run to indicate that the autoclave contents have been processed.

c. Records of autoclave operations shall be maintained for every cycle. Records shall include date, contents, maximum temperature reached, pressure, time in sterilization mode, total run time (may be recorded as time in and time out) and analyst's initials.

d. Autoclave maintenance shall be performed annually, either internally or by service contract, and shall include a pressure check and calibration of temperature device. Records of the maintenance shall be maintained in equipment logs. If the laboratory demonstrates regular monitoring of pressure (e.g., for each autoclaved batch) and annual calibration of the maximum registering thermometer, the annual autoclave pressure and temperature device checks shall not be required.

e. The autoclave mechanical timing device shall be checked quarterly against a stopwatch and the actual time elapsed documented.

3. Volumetric equipment. Volumetric equipment shall be calibrated as follows:

a. Equipment with movable parts such as automatic dispensers, dispensers/diluters, and mechanical hand pipettes shall be verified for accuracy quarterly.

b. Equipment such as filter funnels, bottles, nonclass A glassware, and other marked containers shall be calibrated once per lot prior to first use.

c. The volume of the disposable volumetric equipment such as sample bottles and disposable pipettes shall be checked once per lot.

4. UV instruments. UV instruments used for sanitization shall be tested quarterly for effectiveness with an appropriate UV light meter or by plate count agar spread plates. Replace bulbs if output is less than 70% of original for light tests or if count reduction is less than 99% for a plate containing 200 to 300 organisms.

5. Conductivity meters, oxygen meters, pH meters, hygrometers, and other similar measurement instruments shall be calibrated according to the method specified requirements (see 1VAC30-45-740 D 1 d).

6. Incubators, water baths, and ovens.

a. The uniformity of temperature distribution in incubators and water baths shall be established. Temperature of incubators and water baths shall be documented twice daily, at least four hours apart, on each day of use.

b. Ovens used for sterilization shall be checked for sterilization effectiveness monthly with appropriate biological indicators. Records shall be maintained for each cycle that include date, cycle time, temperature, contents and analyst's initials.

7. Labware (glassware and plasticware).

a. The laboratory shall have a documented procedure for washing labware, if applicable. Detergents designed for laboratory use shall be used.

b. Glassware shall be made of borosilicate or other noncorrosive material, free of chips and cracks, and shall have readable measurement marks.

c. Labware that is washed and reused shall be tested for possible presence of residues that may inhibit or promote growth of microorganisms by performing the Inhibitory Residue Test annually, and each time the lab changes the lot of detergent or washing procedures.

d. Washed labware shall be tested at least once daily, each day of washing, for possible acid or alkaline residue by testing at least one piece of labware with a suitable pH indicator such as bromothymol blue. Records of tests shall be maintained.

Historical Notes

Derived from Volume 25, Issue 07, eff. January 1, 2009; amended, Virginia Register Volume 32, Issue 22, eff. September 1, 2016.

Statutory Authority

§ 2.2-1105 of the Code of Virginia.