Only those instruments that are needed to analyze for the
parameters for which the laboratory is being certified are required, but those
instruments shall meet the following minimum specifications. A laboratory
performing all of the analyses described in Section
465.360 shall have, or have
access to, within the same building, all of the equipment listed in this
Section with the minimum specifications cited.
a) A top loading or trip pan balance shall be
clean, not corroded.
1) A torsion or trip pan
balance used for weighing materials of 2 grams or more shall detect 100 mg of
weight accurately at a 150 gram load.
2) An analytical balance used for weighing
quantities of less than 2 grams shall be sensitive to 1 mg at a 10 gram
load.
b) A magnetic
stirrer shall be capable of achieving variable speeds and shall be used with a
Teflon-coated stirring bar. The magnetic stirrer may be equipped with a heating
element.
c) A pH meter shall have
an accuracy of at least ± 0.1 units and a scale readability of at least
± 0.1 units. The pH meter may be either line/bench or battery/portable
operated. pH meter must be able to calculate slope.
d) A conductivity meter and cell combination,
suitable for checking laboratory pure water quality, shall be readable in ohms
or mhos, and have a range capable of determining the conductivity or
resistivity of laboratory pure water as described in Section
465.380(a). The
conductivity meter may be either line/bench or battery/portable
operated.
e) An autoclave shall be
horizontal-chambered and shall meet all of the following specifications:
1) When observed during the operational cycle
or when time-temperature charts are read, the autoclave shall be in good
operating condition;
2) An
operating safety valve shall be included;
3) Separate temperature and pressure gauges
shall be located on the exhaust side;
4) The autoclave shall reach and maintain a
temperature of 121°
± 1° C during the sterilization cycle, and
no more than 45 minutes shall be required for a complete cycle of carbohydrate
media;
5) Depressurization shall
not produce gas bubbles in fermentation media; and
6) Pressure cookers shall not be
used.
f) A hot-air
sterilization oven shall operate at a minimum of 175° C, shall be equipped
with a thermometer inserted through the top porthole or be equipped with a
temperature-recording device, and shall be equipped with a thermostatic control
that will not allow the temperature to deviate by more than ± 5° C
from the temperature setting.
g) An
incubation unit shall maintain an internal temperature of 35°
± 0.5
° C or 44.5 °
± 0.2 ° C and shall be of the following type:
air or water jacketed incubator, incubator room, water bath, or aluminum block
incubator. Incubation units of the aluminum block type shall have culture
dishes and tubes that are snug fitting in the block. Water baths shall be
circulating with covers. Laboratories that use the enzyme substrate tests with
air-type incubators shall note the product incubation details indicated in
Section
465.360(j)(7).
h) An ultraviolet (UV) sterilizer shall be
free from radiation leaks and shall be UV efficiency tested quarterly as
described in "Standard Methods for the Examination of Water and Wastewater."
Proper eye protection shall be available for users of the ultraviolet
sterilizer. The ultraviolet sterilizer shall not be used as a substitute for an
autoclave. The unit shall be disconnected monthly and the lamps cleaned by
wiping with a soft cloth moistened with ethanol.
i) A refrigerator shall maintain a
temperature of between 1° and 5° C and shall be equipped with a
thermometer located on the top shelf. The thermometer shall be graduated in not
greater than 1° C increments, and the thermometer bulb shall be immersed in
liquid unless otherwise specified by the manufacturer of the temperature
monitoring system.
j) An agar
tempering water bath shall be of appropriate size for holding melted medium and
shall be thermostatically controlled at 45°
± 1° C.
k) The following standards shall apply to
temperature-monitoring devices:
1) Glass or
electronic thermometers shall be graduated in not greater than 0.5° C units
for use in 35° C incubators.
2)
Glass or electronic thermometers shall be graduated in not greater than
0.2° C units for use in 44.5° C water baths or aluminum block type
incubators.
3) Glass or electronic
thermometers shall be graduated in not greater than 1.0 ° C units for use
in spore incubators required for autoclave quality control.
4) Electronic thermometers with
thermocouplings and continuous temperature-recording devices shall be sensitive
to not greater than 0.5° C when used in 35° C incubators, shall be
sensitive to not greater than 0.2° C when used for 44.5° C water baths
or aluminum block type incubators, and shall be sensitive to not greater than
1° C when used in spore incubators required for autoclave quality
control.
5) An NIST certified
thermometer, or one of equivalent accuracy graduated in 0.2° C or less,
shall be available for calibration use and shall be accompanied by its
certification papers and procedures for use. All thermometers and
temperature-recording devices shall be calibrated annually at temperature of
use against the certified thermometer to within ± 1.0° C.
6) Each laboratory operating an autoclave
shall have either a maximum registering thermometer, an autoclave with an
internal digital temperature record, or a datalogger in the range of 80° to
200° C graduated in increments no greater than 1° C.
7) Each laboratory shall use separate
thermometers for determining the temperatures of water baths, ovens,
autoclaves, samples, refrigerators, storage areas, etc.
8) The liquid column of glass thermometers
shall have no separations.
9) Dial
and infrared thermometers are not permitted.
l) Optical counting equipment shall include a
low-power magnification device of the dissecting or stereomicroscope type with
a magnification power of 10 to 15 diameters, and an external daylight
fluorescent light source for sheen discernment at an angle of 60° to
80° above the colonies.
m) A
mechanical hand tally shall be available for counting colonies on membrane
filters or agar pour plates.
n)
Where metal inoculation loops are used, loops shall be of 22 to 24 gauge
chrome, or platinum-iridium wire, with loop diameters of at least 3 mm. Hot-air
sterilized wooden applicator sticks, pre-sterilized cotton swabs or
pre-sterilized plastic loops may be used.
o) Membrane filter equipment shall be
non-leaking, uncorroded, and made of stainless steel, glass, or autoclavable
plastic. Disposable single-use equipment made of plastic is also acceptable.
Metal plating on membrane filter equipment shall not be worn so as to expose
base metal.
p) Membrane filters
shall be white, grid marked, 47 mm diameter, with 0.45 micron pore size, and
made from cellulose ester materials. Another pore size may be used if the
manufacturer gives performance data equal to or better than the 0.45 micron
membrane filter. Membrane filters shall be autoclavable or
presterilized.
q) Absorbent pads
shall be of uniform thickness to permit 1.8 to 2.2 mL media absorption and
shall be autoclavable or presterilized. Filter paper shall be free from
growth-inhibiting substances.
r)
Forceps used to handle membrane filters and absorbent pads shall have a round
tip without corrugations.