Code of Massachusetts Regulations
310 CMR - DEPARTMENT OF ENVIRONMENTAL PROTECTION
Title 310 CMR 42.00 - Certification And Operation Of Environmental Analysis Laboratories
Section 42.08 - Minimum Standards for Certification

Universal Citation: 310 MA Code of Regs 310.42

Current through Register 1537, December 20, 2024

(1) Personnel. Certified laboratories and laboratories seeking certification shall designate a laboratory director and laboratory supervisor(s), and employ a sufficient number of qualified analysts commensurate with the laboratory's workload. The designated laboratory director and laboratory supervisor may be the same individual if he or she possesses the minimum qualifications and fulfills the responsibilities of both positions as set in 310 CMR 42.08(1).

(a) The laboratory director shall have the following responsibilities:
1. Developing policies, programs, and standard operating procedures that will ensure accurate and objective analytical results;

2. Employing and ensuring the training of qualified laboratory personnel;

3. Reporting analytical results to the Department in accordance with 310 CMR 42.13; and

4. Interpreting and evaluating reports of analyses submitted by the laboratory upon request of the Department.

(b) A laboratory supervisor shall have the following responsibilities:
1. Performing analyses and/or providing personal and direct supervision and training to laboratory analysts performing analyses in the categories for which the supervisor is qualified;

2. Instruction and general supervision of all other laboratory operations including sample tracking, data validation, quality control, verification, and prompt reporting of results; and

3. Acceptance and non-acceptance of samples submitted to the laboratory for analysis.

(c) Minimum Qualifications of Laboratory Director.
1. Academic Training. The laboratory director shall possess a Bachelor's degree in biology, chemistry, or a closely related field. If chemical analyses are to be performed by the laboratory, the director must have at least 24 college credits in chemistry.

2. Experience. The laboratory director shall have a minimum of three years of experience in an environmental analysis laboratory.

(d) Minimum Qualifications of Laboratory Supervisor for Laboratories Certified in the Discipline of Chemistry or Radiochemistry.
1. Academic Training. The laboratory supervisor shall possess a Bachelor's degree in chemistry, biology, or a closely related field, and have at least 30 college credits in chemistry.

2. Experience.
a. Chemistry. The laboratory supervisor shall have a minimum of two years of laboratory experience in chemical analysis including one year of experience in the specific chemical methods supervised.

b. Radiochemistry. The laboratory supervisor shall have a minimum of two years of laboratory experience in radiochemical analyses, including one year of experience in the radiochemical methods for which the laboratory is certified.

(e) Minimum Qualifications of Laboratory Supervisor for Laboratories Certified in the Discipline of Microbiology.
1. Academic Training. The laboratory supervisor shall have a minimum of a Bachelor's degree in biology, chemistry, or a closely related field with at least four college credits in microbiology.

2. Experience. The laboratory supervisor shall have a minimum of one year of experience in the microbiological methods for which the laboratory is certified.

(f) Minimum Qualifications of Instrumentation Analyst.
1. Academic Training. An instrumentation analyst shall possess a minimum of a high school diploma or equivalent and eight college credits in chemistry.

2. Experience. An instrumentation analyst shall have a minimum of one year of training or experience in the operation of the appropriate instrumentation.

(g) Minimum Qualifications of Analyst.
1. Academic Training. An analyst shall possess a minimum of a high school diploma or equivalent.

2. Training. An analyst shall receive specialized training in the methods to be performed.

(h) The Department may exempt a laboratory holding certification status on the effective date of 310 CMR 42.00 from one or more of the requirements set forth in 310 CMR 42.08(1), if the Department finds that strict compliance with such requirements would result in an undue hardship and would not serve to further the intent of 310 CMR 42.00. An exemption, when granted, shall be effective for not more than one year unless renewed by the Department.

(2) Facilities. A certified laboratory shall have:

(a) Adequate space in which to perform the analyses and related activities in the disciplines and categories in which it is certified;

(b) A well-lighted laboratory work bench area of ample size that is convenient to a sink, hot and cold running water, gas, suction, and electrical outlets if necessary;

(c) Clear aisles between benches that provide adequate room for passage of personnel and equipment;

(d) Appropriate ventilation including exhaust hoods for the handling of chemicals and samples in order to limit contamination of samples, standards, and other laboratory areas with the performance of each exhaust hood and biological safety cabinet tested by a qualified person annually and determined to be operating satisfactorily;

(e) Appropriate facilities for the storage of volatile, corrosive, and flammable materials;

(f) Controlled laboratory temperature and humidity at the levels required for the proper performance of the analyses and for the optimum operation of instruments that are sensitive to variations in temperature; and

(g) A locked facility for storage of chain-of-custody samples.

(3) Equipment and Materials. Certified laboratories and laboratories seeking certification shall have readily available on the premises all equipment, supplies, reagents, glassware, and instrumentation necessary to perform the analyses for which the laboratory is certified or seeks certification and related quality control activities. Such equipment and materials shall be maintained in good working condition, meet the performance criteria of the analytical method used, and, where appropriate, meet the criteria specified in 310 CMR 42.08(3):

(a) Refrigerator. Aqueous reagents and samples may be stored in a standard household refrigerator. A flammable materials refrigerator shall be used for storage of organic s and flammable materials. The internal temperature of a refrigerator shall be maintained at 4°C ± 2°C. Organics and flammable materials not requiring refrigeration shall be stored in a flammable storage cabinet.

(b) Drying Oven. The drying oven shall have selectable temperature control with a range from room temperature to 180°C ± 2°C or higher.

(c) Source of Distilled or Deionized Water. Distilled or deionized water shall meet the minimum criteria of the methodologies employed.

(d) Top-loader Balance. The balance pan shall be clean and free of corrosion. The balance must be capable of detecting a weight of 100 mg at a 150 g load or one mg for a load of 10 g or less.

(e) Hot Plate. The hot plate shall have selectable temperature controls for safe heating of laboratory reagents.

(f) Magnetic Stirrer. The magnetic stirrer shall be of variable speed with a stirring bar coated with inert material.

(g) Glassware. Glassware shall be made of borosilicate glass. Volumetric glassware shall be marked "Class A".

(h) Analytical Balance. The analytical balance shall be readable to 0.1 mg. It shall be mounted on a stable shock-proof base and protected from interference due to air currents.

(i) Conductivity Meter. The conductivity meter shall be readable in appropriate units, have a range from 2 ohms to 2 megohms or equivalent micromhos or Siemens, and be capable of measuring conductivity with an error not exceeding ± 1 % or one µS/cm, whichever is greater.

(j) pH Meter. The pH meter shall be accurate to at least ± 0.05 units and have scale readability to ± 0.01 units.

(k) Thermometer. The thermometer shall have 1°C or finer subdivisions and be calibrated in degrees Celsius for the temperature range in which it will be used. The column shall have no separations. An organic solvent-filled thermometer may be used in a refrigerator. The laboratory may use electronic temperature measurement devices having the appropriate accuracy and readability for their intended use.

(l) Water Baths. Water baths may be electric or steam heated and capable of controlling temperature to 100°C within 5°C.

(m) Incubators. Incubators shall have an internal temperature-monitoring device and be capable of maintaining proper temperature.

(n) Autoclave. The autoclave shall be equipped with an accurate thermometer, a separate pressure gauge, and an operational safety valve. It shall maintain the sterilization temperature throughout the sterilization cycle and depressurize slowly so that no air bubbles form in inverted tubes and medium does not boil over. When being used to sterilize carbohydrate-containing media, the autoclave must be capable of completing an entire cycle (i.e., time when materials are exposed to heat) within 45 minutes when a 12-15 minute sterilization period is used.

(o) Hot-air Sterilization Oven. Hot-air sterilization ovens shall be capable of maintaining a stable sterilization temperature (170°C - 180°C).

(p) Muffle Furnace. Muffle furnaces shall be capable of heating glassware to 400°C for cleaning.

(q) Reagents, Standards, Media. Consumable supplies such as, but not limited to, reagents, standards, and media must not be used beyond their expiration date.

(r) Stereo Microscope. Stereo microscopes must have a magnification of 10-15x and be equipped with a fluorescent light source.

(s) Colony Counter. When the pour plate technique is used, a dark-field colony counter must be used to count heterotrophic plate count colonies.

(4) Laboratory Safety Measures Affecting Laboratory Analysis Capability. Certified laboratories shall be in compliance with local, state, and federal laws to the extent that required conditions directly affect laboratory capability in providing accurate and reliable analysis and maintaining the integrity of samples and of the analytical process; or are referenced as required for environmental laboratories by the acceptable analytical method(s) employed. These conditions include, but are not limited to, safety protocols involving physical, chemical, radiochemical, and biological hazards; availability and use of fire safety equipment; protective clothing and equipment including respirators; appropriate handling of compressed gas cylinders; and appropriate storage and disposal of materials and wastes.

(5) Quality Assurance/Quality Control

(a) General Requirements.
1. Quality Assurance Plan. Certified laboratories shall establish, maintain, and follow a written Quality Assurance (QA) Plan acceptable to the Department. Each laboratory's QA plan shall be made available to all analysts employed by the laboratory. At a minimum, QA plans shall include:
a. QA organization and responsibility;

b. QA objectives for precision and accuracy;

c. Standard operating procedures (SOPs) that accurately reflect all phases of current laboratory activities. The standard operating procedures section of a laboratory's QA plan shall include the following:
i. Sample receipt and handling procedures including sample custody and storage procedures;

ii. Calibration procedures and frequencies;

iii. Analytical procedures, including any modifications to published procedures;

iv. Data reduction, validation and reporting procedures;

v. Internal quality control procedures (type and frequency);

vi. Provision for performance and system audits, both internal and external, and schedules;

vii. Preventive maintenance procedures and schedules;

viii. Specific procedures for assessing data precision and accuracy;

ix. Procedures for taking corrective actions;

x. Quality assurance reporting procedures; and

xi. Laboratory safety plans.

A standard operating procedure for an analytical method or other laboratory procedure may be a separate document. The QA plan must include a list of all such standard operating procedures. Only the laboratory director or supervisor may make changes in standard operating procedures. Such changes shall be effective only when put in writing.

d. Record Maintenance. The record maintenance procedures section of a laboratory's QA plan shall include the procedures for creating, controlling, and maintaining the following records:
i. Raw data (including, but not limited to, laboratory notebooks, instrument printouts, and electronic records);

ii. Chain-of-custody records;

iii. Calculations;

iv. Quality control data; and

v. Reports.

2. Temperature Records.
a. A laboratory shall measure and record the temperature of each drying oven and hot-air sterilizing oven for each day of use. The temperature measurement device must be immersed in sand or other suitable material and placed on one of the shelves. A laboratory may use a temperature-measuring device that can be read from outside the oven without the need to open the door provided that it has verified the accuracy of the device.

b. A laboratory shall measure and record the temperature of each refrigerator and incubator either continuously or each day of use. The thermometers must be immersed in liquid and placed on one of the shelves. A laboratory may use a temperature-measuring device that can be read from outside the refrigerator or incubator without the need to open the door provided that it has verified the accuracy of the device.

3. Laboratory Chemicals and Reagents. Analytical reagent (AR) grade or American Chemical Society (ACS) grade chemicals or better are required for analyses, unless otherwise required by the analytical method. In addition, laboratory chemicals and reagents shall meet the following requirements:
a. All chemicals shall be labeled with the date of receipt by the laboratory to prevent the use of outdated reagents;

b. Stock and working standard solutions shall be compared with check standards and inspected prior to use for signs of decomposition, such as formation of precipitates, evaporation, and/or discoloration;

c. All reagents and standards shall be labeled with identification of the compound, concentration, solvent, date of preparation, date of expiration, and the name of the analyst who prepared the solution;

d. Preparation of all stock standards and primary dilution standards shall be documented, and the concentration of stock and working calibration standards shall be verified against a primary dilution standard prepared from a source of reagents different from those used to prepare the calibration standards; and

e. The use of the acceptable grade of reagents and compressed gases required by the analytical procedure employed shall be documented.

4. Laboratory Glassware. The laboratory must follow cleaning procedures for glassware and other labware that are specified in the analytical methods. If no specifications are given in a method, then glassware and sample containers must be cleaned prior to use by washing in a warm detergent solution, followed by thorough rinsing with tap water and several additional rinses using deionized or distilled water. The laboratory must use a detergent designed for laboratory use. Commercially prepared glassware and sample containers may be used provided the laboratory documents the source and cleaning procedures utilized. Certain analytical methods may require additional glassware preparation procedures or the maintenance of a separate dedicated set of glassware.

5. Maintenance of Laboratory Instrumentation and Equipment. Analytical instrumentation and equipment shall be maintained in accordance with the manufacturer's instructions, analytical method requirements, and good laboratory practices. A secure record of maintenance procedures shall be maintained for each instrument and piece of equipment.

6. Instrumentation Calibration Requirements.
a. General Requirements.
i. Unless directed otherwise by the analytical method employed, all instruments shall be calibrated immediately prior to analysis using a minimum of a blank and three calibration standards that bracket the expected concentration range,

ii. Unless directed otherwise by the analytical method employed, all instrument calibrations shall be verified through the analysis of a calibration check sample that has been prepared using a source of reagents different from that used to prepare the calibration standards. Unless directed otherwise by the analytical method employed, the calibration check sample shall be analyzed at the beginning and at the conclusion of the analysis session and after every 20 or fewer samples. If the result does not agree within 20% of the original value, corrective action shall be taken.

iii. For instruments with a calibration curve that has been set by the instrument manufacturer, the laboratory shall verify the calibration curve using a minimum of three calibration check standards that bracket the expected concentration range. The check standards shall represent low, medium, and high concentrations and include a standard at the minimum reporting level (MRL). If the result of the calibration check does not agree within 10% of the assigned value of each check standard, instrument recalibration must be performed.

iv. The laboratory shall keep a secure record of instrument calibration procedures.

b. Analytical Balance. Each analytical balance shall be checked and adjusted annually by a qualified service person. The accuracy of each analytical balance shall be checked each day it is to be used using a minimum of two ASTM Class 1 weights, or equivalent, in ranges appropriate to the laboratory's weighing needs. The laboratory shall keep a secure record of the results of accuracy checks, the date performed, and the signature of the analyst who performed the check. The non-reference weights used for this check must be calibrated annually using reference weights and the results recorded. The accuracy of reference weights must be certified every five years. The balance level shall be checked prior to each use and adjusted if necessary.

c. pH Meters. Each pH meter shall be calibrated daily or prior to each use with pH 7.0 and pH 4.0 or 10.0 buffer standards that bracket the expected value of the sample, medium, or reagent being tested. The buffers used shall be recorded, including the date of calibration and the name of the analyst who performed the calibration.
i. The laboratory must use pH buffer aliquots only once.

ii. The laboratory must date commercial buffer solution containers upon receipt and when opened.

iii. The laboratory must record the pH meter slope monthly after calibration and take corrective action if the slope falls outside the range of 95% to 105%.

d. Conductivity Meters.
i. The conductivity meter must be calibrated at least monthly using a certified and traceable low-level standard. Alternatively, the laboratory must determine the cell constant monthly.

ii. An in-line meter may be used to check reagent-grade water provided that it is calibrated annually.

e. Thermometers. The accuracy of all temperature measurement devices used to monitor temperatures shall be verified by comparing the reading of each device with that of a certified reference thermometer that is graduated in degree increments no larger than those of the device whose accuracy is being verified. The laboratory must discontinue use of a thermometer graduated in 0.5°C increments or less that differs from the certified thermometer by more than 1°C. The accuracy of glass and electronic thermometers must be verified annually; metal thermometers must be verified quarterly; infrared detection devices must be verified every six months; and the certified reference thermometer must be calibrated at least once every five years. The correction factor and date of verification of accuracy must be indicated on the thermometers. The laboratory shall maintain a secure record that includes:
i. The identification number of each thermometer;

ii. The temperatures displayed on both the certified thermometer and the thermometer being verified;

iii. Any applicable correction factor;

iv. The date each check was performed; and

v. The signature of the analyst who performed each check.

f. On-line Monitors and Portable Equipment. Continuous on-line monitors and portable equipment used in obtaining on-site measurements must be calibrated in accordance with the manufacturer's instructions. The calibration must be verified through analysis of an independent check sample or use of an independent monitoring technique. Verification shall be recorded.

g. Spectrophotometer Wavelength Verification. The wavelength setting of the spectrophotometer shall be checked annually by comparing the wavelength setting to that of colored standards or filters, such as didymium glass. The wavelength observed, date of performance, and the name of the analyst or service person that performed the check shall be recorded.

h. Top-loader Balance. Each top-loader balance must be checked for accuracy monthly in its range of use with ASTM Class 1 weights or equivalent.

7. Sample Collection, Preservation and Handling.
a. Acceptable procedures, as referenced or defined in current federal regulations shall be utilized for sample collection, handling and preservation.

b. The laboratory may reject the sample if it is not assured of the sample identification or of the validity of the sample collection, handling and preservation procedures. The laboratory must have a written policy listing its criteria for rejection of samples. When rejecting a specific sample, the laboratory must document the reason(s) for the rejection.

c. Samples shall be stored in such a way that cross-contamination from other samples, standards or reagents is avoided.

d. The laboratory shall adhere to the sample and extract holding times prescribed in the analytical methods.

e. Chain-of-custody information must include:
i. Sample number;

ii. Sample description including any preservation (e.g., chemical, thermal, etc.) used;

iii. Date and time of sample collection;

iv. Specific location of sample collection;

v. Name of sample collector and intermediate custodians, if any;

vi. Date(s) and time(s) of custody transfer to the laboratory; and

vii. Name(s) and signature(s) of the individual(s) receiving the sample.

f. A chain-of-custody form must accompany all samples including those shipped by mail or courier.

g. The laboratory shall maintain a system of internal sample tracking that documents sample custody from the time of receipt at the laboratory to the time of disposal.

8. Analytical Methodology. The laboratory shall utilize acceptable analytical methods. The acceptable methods shall be those defined or referenced in 40 CFR parts 136, 141 and 143, and 310 CMR 22.00: Drinking Water, for the environmental matrix being tested.

(b) Additional Requirements for Chemical and Radiochemical Laboratories.
1. Quality Control Procedures.
a. Unless directed otherwise by the analytical method or the Department standard employed, the laboratory shall prepare and analyze a laboratory reagent blank, sample duplicate, and laboratory fortified blank for every 20 or fewer samples processed as an analytical batch. Duplicates of radiochemical samples must be prepared and analyzed for every ten or fewer samples. In addition, a laboratory fortified sample matrix shall be run if required by the Department. Corrective action shall be taken if the results of these analyses do not meet acceptance criteria developed within the laboratory according to accepted analytical procedures. The preparation of blanks, laboratory fortified sample matrices, and duplicates and the results of their analyses shall be recorded.

b. Each laboratory must establish acceptance limits for precision and accuracy and maintain and use quality control charts for each of the analytes in the matrices, disciplines, and categories in which the laboratory is certified. These limits may not be less stringent than those defined in approved analytical methods or approved by the Department.

c. Certified laboratories shall utilize surrogate analytes as required by the analytical procedure employed. Acceptance limits for surrogate analyte recoveries shall be established by the laboratory. Quality control charts must be maintained and used for each surrogate.

d. Certified laboratories shall perform and document all quality control procedures in established analytical protocols or the quality control procedures the Department requires and specifies.

e. When integrating chromatography peaks, either automatically or manually, each laboratory must ensure that integrations are performed in a correct and consistent manner for standards and samples, including quality control samples. Each laboratory must maintain documentation of manual integrations that includes the following:
i. The laboratory's written procedure for manual integration;

ii. The original chromatogram and the manually integrated chromatogram; and

iii. The analyst's initials, date of manual integration, and the reason(s) for the manual integration.

2. Determination of Method Detection Limit.
a. Each laboratory shall experimentally determine the method detection limit for analysis of each analyte, except pH, for each matrix in which the laboratory is certified.

b. The laboratory must document its procedure for determining the method detection limit. The laboratory must use the procedure for determining the method detection limit that is described in the analytical method being used. If the analytical method does not include a procedure for the determination of method detection limits, then the laboratory must determine the method detection limit using the procedure described in 40 CFR Part 136: Appendix B or other Department- or EPA-approved procedure. For those analytes requiring pattern recognition for identification (e.g., chlordane, toxaphene), the method detection limit is defined as the lowest concentration at which pattern recognition is possible.

c. Calculations and supporting documentation used in determining limits must be available for inspection.

d. Detection limits shall be expressed in appropriate units.

e. The laboratory must achieve the method detection limits required by the applicable regulations.

f. Sample preparation and analyses for the method detection limit calculation must be made over a period of at least three days.

g. Method detection limits must be determined as part of a laboratory's initial demonstration of capability to perform an analysis, when any change occurs in the laboratory that could affect the method detection limits, and as required by an analytical method.

h. Method detection limits must be determined using analysts and instruments that are representative of those used in the performance of analyses,

i. The laboratory must verify its capability to analyze low level samples on an ongoing basis through the analysis of low level standards or through a method detection limit determination.

j. The laboratory shall determine the minimum reporting level for analysis of each analyte, except pH, for each matrix in which the laboratory is certified. The laboratory shall document the procedure used to determine the minimum reporting level. The laboratory shall verify the minimum reporting level on an ongoing basis.

3. Laboratory Reagent Water. The laboratory must demonstrate that its reagent water meets the specifications required by the analytical methods it uses including that it is free of analytes of interest above their method detection limits. When the method specifies the resistance or conductivity of the source of reagent water, verification of such quality shall be made and documented each day the water is used.

(c) Additional Requirements for Microbiology Laboratories.
1. Autoclaves.
a. For each sterilization cycle, the signature of the analyst, date, sterilization time and temperature, the materials being autoclaved and their total time in the autoclave shall be recorded.

b. A maximum-temperature-registering thermometer, electronic temperature readout device, or continuous recording device must be used during each autoclave cycle. The temperature must be recorded.

c. Automatic timing mechanisms must be checked quarterly with an accurate timepiece, such as a stopwatch, and the results recorded.

d. The laboratory must check the performance of the autoclave each week during which the autoclave is used with Geobacillus stearothermophilus spore strips, suspensions, or capsules and record the results.

e. Biological waste must be autoclaved for at least 30 minutes followed by proper disposal.

2. Hot Air Sterilizing Ovens. The laboratory must check the performance of the hot air sterilizing oven each week during which the oven is used with Bacillus subtilis or Bacillus atrophaeus spore strips and record the results.

3. Incubators.
a. Incubators, both air-type and water bath, must maintain the temperature specified by the method. On days when the incubator is in use, the temperature of each incubator must be recorded continuously or at least twice per day, with each reading separated by at least four hours and the times of each reading recorded. For air-type incubators, the thermometer shall be immersed in liquid and placed on one of the shelves in use.

b. If an aluminum block incubator is used, culture dishes and tubes must fit snugly.

c. Water bath incubators must be cleaned at least monthly.

d. The laboratory must record the date and time at the beginning and at the end of sample incubation.

4. Germicidal Ultraviolet Lamps. Germicidal ultraviolet lamps shall be tested quarterly by exposing agar spread plates containing 200 to 250 microorganisms to the light for two minutes. If such irradiation does not reduce the count of control plates by 99%, the lamps shall be replaced. Alternatively, the laboratory shall use an ultraviolet light meter to ensure that the lamp emits at least 70% of its initial output. Cleaning of germicidal ultraviolet lamps shall be done at least monthly by disconnecting the unit and cleaning the lamps with a soft cloth moistened with ethanol.

5. Microscopes. The optics and stage of microscopes shall be cleaned with lens paper prior to each use.

6. Sterility of Rinse/Dilution Water and Sample Bottles.
a. Each batch or lot of dilution/rinse water must be checked for sterility by adding 50 mL of the water to a 50 mL volume of a double strength non-selective broth (e.g., tryptic soy broth, trypticase soy broth, or tryptose broth), which is then incubated at 35°C ± 0.5°C and checked for turbidity signifying growth at 24 and 48 hours and the results recorded.

b. After sterilization, at least one bottle per batch of sterilized sample bottles or per lot of commercially prepared sample containers shall be checked for sterility by adding approximately 25 mL of sterile non-selective broth medium 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 35°C ± 0.5°C and checked for growth at 24 and 48 hours and the results recorded. Prepared sample bottles from each batch or lot shall not be used unless satisfactory results are obtained from the tested bottle.

7. Residue Testing of Glassware.
a. Inhibitory Residue Test. With the initial use of each lot of a detergent or washing product, the rinsing process using distilled or deionized water shall be demonstrated to provide glassware that is free from toxic material based on the use of the Inhibitory Residue Test, as specified in the most recent edition of Standard Methods for the Examination of Water and Wastewater, American Public Health Association, American Water Works Association, Water Environment Federation, Washington D.C. The results of the test must be recorded. Alternatively, the laboratory may obtain written, traceable certification from the product manufacturer that the inhibitory residue test has been performed on the lot of detergent or washing product according to the Standard Methods procedure. The actual test results must be included with the certification.

b. Bromthymol Blue Test. Each batch of clean, dry glassware or plasticware shall be tested for residual alkaline or acid residue using bromthymol blue indicator and the results recorded. If the results of the indicator test are not within the desired color range of light green to dark blue, corrective action shall be taken by re-rinsing, air drying and retesting.

8. Microbiological Media - Quality Control Measures.
a. The laboratory shall keep records that indicate the kind, amount, date received, lot number, expiration date, and date of opening of bottles of media. Media shall be stored in a desiccator or cool, dry location. If caking or discoloration of media occurs, media shall be discarded.

b. Records shall be available for inspection on all batches of laboratory-prepared media showing lot numbers, date prepared, details of preparation, total volume prepared, sterilization time and temperatures, final pH, and the name of the individual who performed the work.

c. Prior to first use of media, the laboratory shall test each batch of medium prepared in the laboratory and each lot of pre-prepared, ready-to-use medium with at least one pure culture of a known positive reaction.

d. Prior to first use of media, the laboratory shall test each batch of medium prepared in the laboratory and each lot of pre-prepared, ready-to-use medium with one or more negative culture controls, i.e., non-target organisms, as appropriate to the method.

e. Prepared plates shall be refrigerated in sealed containers with a label containing the date of preparation or expiration and the name of the medium. Plates may be kept no more than two weeks following preparation. Broth media in loose-capped test tubes may be kept no more than two weeks following preparation. Broth media in tightly capped tubes may be kept three months from the date of preparation.

9. Dechlorination Sufficiency. If chlorinated water is to be analyzed, sufficient sodium thiosulfate must be added to the sample bottle before sterilization to neutralize any residual chlorine in the water sample. The laboratory may also use commercially prepared, pre-sterilized bags or bottles containing sodium thiosulfate.

10. Membrane Filter Procedure Quality Control Specifics.
a. Only membrane filters recommended for water analysis by the manufacturer shall be used.

b. Lot numbers of membrane filters and date of receipt shall be recorded.

c. Procedural Contamination. A start and finish membrane filtration control test of rinse water, medium, and supplies shall be conducted for each filtration series. If sterile controls indicate contamination, all data on samples affected shall be rejected and a request made for immediate resampling of those waters affected.

d. Verification of Membrane Filter Colonies on m-Endo medium.

Total Coliform Procedure. All sheen or borderline colonies up to ten on each membrane shall be verified in accordance with the accepted standard procedure contained in the latest edition of Standard Methods for the Examination of Water and Wastewater (Standard Methods).

11. Quality Control.
a. When quality control samples are available, each analyst shall analyze at least one quality control sample per year for the categories to be certified.

b. During the initial training of an analyst in a method requiring the identification and enumeration of colonies, the new analyst must count plates from at least ten positive samples having varying colony counts within the ideal counting range for the method. The laboratory supervisor must count the same plates. The replicate counts between the analysts must agree within 10%.

c. For methods used for the enumeration of colonies, 10% of routine samples must be analyzed in duplicate and the range of logs determined. Corrective action shall be taken if the results of these analyses do not meet acceptance criteria developed within the laboratory according to accepted analytical procedures.

12. Laboratory Reagent Water. The laboratory shall use satisfactorily tested reagent water from a water purification system (e.g., still, deionization unit, or a reverse-osmosis unit) to prepare media, reagents, and dilution/rinse water for performing microbial analyses.
a. If the source water is chlorinated, the laboratory reagent water must be tested monthly for total chlorine residual and found to contain less than 0.1 mg/L of chlorine residual.

b. The laboratory reagent water must be analyzed annually for the presence of lead, cadmium, chromium, copper, nickel, and zinc. The concentration of each metal must be no greater than 0.05 mg/L. The concentration of the metals collectively must be no greater than 0.1 mg/L.

c. The conductivity of the laboratory reagent water must be monitored each day that the water is used and found to be less than 2 µS/cm at 25°C or greater than 0.5 megohms-cm resistance at 25°C.

d. A heterotrophic plate count must be performed on the laboratory reagent water monthly. The laboratory may use the reagent water only if the heterotrophic plate count is less than 500 CFU/mL.

e. The test of the bacteriological quality of the laboratory reagent water must be performed annually. The ratio of the growth rate must be between 0.8 and 3.0. The test is described in Section 9020B of the 18th and 19th editions of Standard Methods for the Examination of Water and Wastewater. The bacteriological quality test is not required of laboratories that document that their laboratory reagent water meets the criteria for Type II water or better, as defined in Standard Methods (18th and 19th editions), Section 1080C or Medium quality water or better as defined in Standard Methods (20th edition), Section 1080C.

(6) On an annual basis, certified laboratories and laboratories seeking certification shall require all personnel to participate in a laboratory ethics training program. Training shall include the following topics: proper procedures to ensure data integrity, recognition and prevention of improper laboratory practices, the promotion of objectivity and impartiality in the generation and reporting of analytical data, and procedures for confidential reporting of data integrity concerns to a laboratory supervisor, director, or owner, as appropriate. The laboratory must document the content of the training and the date of participation in the training for each staff member and shall make this documentation and the materials used in the training available for review during an inspection.

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