Section 465.400  Quality Controls for Media, Equipment and Supplies

The following minimum requirements shall apply to quality control checks of laboratory media, equipment, and supplies:

a)         The pH meter(s) shall be clean and calibrated each day of use with pH 4, pH 7 and pH 10 standard buffers. The reading shall be within 0.1 unit for the pH of the third buffer. Alternatively pH 7 and either pH 4 or pH 10 buffers shall be used with percent slope determined. Percent slope shall be 95 to 102%. Each buffer aliquot shall be used only once. Commercial buffer solutions shall be dated on initial use. Do not use past the expiration date. Maintain electrodes according to manufacturer's recommendations.

b)         Balances shall be calibrated monthly using NIST standardized Class "S" or "S-1", or equivalent ASTM 1, 2, or 3, weights. A minimum of 3 weights which bracket the weighing requirements of the laboratory shall be used and these weights shall be recertified every 5 years. A certificate listing correction data shall accompany the weights. Electronic balances shall be calibrated annually by a qualified service representative who is not affiliated with the laboratory. A certificate of calibration from the service representative should be available for inspection.

c)         Glass thermometers or continuous temperature recording devices for incubators shall be checked at least annually for accuracy and metal thermometers shall be checked at least quarterly for accuracy against an NIST certified thermometer, or one of equivalent accuracy.

d)         Temperature in incubation equipment shall be recorded continuously by a temperature recording device or recorded twice daily (at times separated by at least 4 hours) from in-place thermometers immersed in liquid and placed on the top and bottom shelves of the use area.  Temperature readings from walk-in incubators with a continuous temperature reading device shall be supplemented by readings from in-place thermometers placed on various shelves other than where the recorder probe is located.

e)         Date, time, duration, and temperature of autoclaving shall be recorded continuously or recorded for each sterilization cycle. A list of materials sterilized in each cycle shall also be maintained and shall be initialed by the person(s) involved. Charts, if used, are to accompany written records.

f)          Hot air oven(s) shall be equipped with a thermometer registering up to at least 180º C, or with a temperature recording device. The oven thermometer shall be graduated in 10º C increments or less, with the bulb placed in sand during use. Date, time, duration, and temperature shall be recorded for each sterilization cycle. A list of materials sterilized in each cycle shall also be maintained and shall be initialed by the person(s) involved in the sterilization process.

g)         Only membrane filters recommended for water analysis by the manufacturer shall be utilized. Manufacturer data sheets containing information as to lot number, ink toxicity, recovery, retention, and absence of growth promoting substances for membrane filters shall be entered into the laboratory's record system. Membrane filters with new lot numbers shall be compared with membrane filters previously found acceptable using Student's t test. Unacceptable membranes shall be returned to the vendor. The lot numbers of membrane filters and date received shall be recorded.

h)         Washing processes shall provide clean glassware with no stains or spotting.  Use distilled or deionized water for final rinse.  With initial use of a detergent or washing product and annually thereafter, the rinsing process with distilled or deionized water shall be demonstrated to provide glassware free of toxic material based on the Inhibitory Residue Test as specified in "Standard Methods for the Examination of Water and Wastewater."

i)          A representative piece of each type of glassware or plastic ware from each batch of clean, dried glassware or plastic ware shall be tested for residual alkaline or acid residue using bromothymol blue indicator.  If the result of the indicator test is not green, corrective action shall be taken by re-rinsing, then air drying and retesting.

j)          At least one bottle per batch of sterilized sample bottles shall be checked for sterility by adding approximately 25 ml of sterile non-selective broth media to each bottle. The bottle shall be capped and rotated so that the broth comes in contact with all surfaces and shall be incubated at 35º + 0.5º C for 24 hours prior to checking for growth.  Prepared sample bottles from each batch shall not be used unless satisfactory results are obtained from the tested bottle.

k)         At least one bottle per batch of sterilized sample bottles prepared with sodium thiosulfate shall be checked for sufficient amount of the dechlorinating reagent by collecting a potable sample at the laboratory tap, then checking for residual chlorine in compliance with the Sample Collector's Handbook, Illinois Environmental Protection Agency, April 1989. Corrective action shall be taken if there is any residual chlorine, and bottles from the batch checked shall not be used until corrective action has been completed.

l)          Current service contracts or in-house protocols shall be maintained on balances, autoclaves, hot-air sterilization ovens, water stills, deionizers, reverse osmosis apparatus, water baths, incubators, etc. Service records on such equipment shall include the date, name of the servicing person, and a description of the service provided.

m)        Records shall be available for inspection on all batches of sterilized media showing type of medium, lot numbers, date, sterilization time and temperatures, final pH, and name of the person(s) responsible for all or any part of the recorded data. The final pH of the medium shall be:

n)         Positive and negative cultures, or a natural water of known pollution, shall be used on each new lot of medium to determine performance compared to a previous acceptable lot of medium. For media which give actual colonies to count, use Student's t test determining acceptability. For all other media check a minimum total of 10 tubes each of old and new lot numbers. The results shall differ by no more than 10%.

o)         A maximum registering thermometer shall be used weekly to verify sterilization temperatures within autoclaves and hot-air sterilizing ovens. The oven maximum registering thermometer shall be placed in sand. The autoclave maximum registering temperature shall be placed in a container of water. Use spore strips or ampules on a weekly basis, including a positive control. A record of these results shall be maintained to include the date, material sterilized, and the initials of the analyst involved. Check automatic timing mechanisms on autoclaves quarterly with a stopwatch. For a 15-minute sterilization period, the autoclave time shall be within 60 seconds of the clock time.

p)         When media dispensing apparatus is used, the media preparer shall check and maintain a record of the accuracy of the dispenser with a graduated cylinder at the start of each volume change and periodically throughout extended runs.

q)         The refrigerator temperature shall be determined daily by an accurate thermometer immersed in liquid and placed on the top shelf. The refrigerator unit shall be cleaned at least monthly. Outdated materials in the refrigerator and freezer compartments shall be discarded.

r)          Ultraviolet sterilization lamps shall be tested quarterly by exposing agar spread plates containing 200 to 250 microorganisms to the light for 2 minutes. If such irradiation does not reduce the count of control plates by 99 percent, the lamps shall be replaced. Cleaning of ultraviolet sterilization lamps shall be done at least monthly by disconnecting the unit and cleaning the lamps with a soft cloth moistened with ethanol.

s)         Water baths shall be cleaned at least monthly. The use of distilled or deionized water for water baths is recommended.

t)          Media shall be used on a first in, first out basis. Records shall be kept of the kind, amount, date received, and date opened for bottles of media. The date opened and the date received shall be written on the bottles. Bottles of media shall be used within 6 months after opening, except that media stored in a desiccator may be used up to one year after opening. It is recommended that media be ordered in quantities to last no longer than one year, and that media be ordered in quarter pound multiples rather than one pound bottles in order to keep the supply sealed and protected as long as possible. Any media that has passed the manufacturer's expiration date shall be discarded.

u)         Conductivity meters shall be calibrated monthly with a 0.01 M KCl solution or lower concentration if desired. The meter reading shall be within 1% of the value of the standard. Calibration is not required for in-line conductivity meters, unless used to determine compliance with quality control requirements.