New Jersey Administrative Code
Title 7 - ENVIRONMENTAL PROTECTION
Chapter 18 - REGULATIONS GOVERNING THE CERTIFICATION OF LABORATORIES AND ENVIRONMENTAL MEASUREMENTS
Subchapter 4 - MICROBIOLOGICAL TESTING
Section 7:18-4.4 - Requirements for general environmental laboratory practices

i. The times for autoclaving materials at 121 degrees Celsius are listed below. Except for membrane filters and pads and carbohydrate-containing media, indicated times are minimal times which may necessitate adjustment depending upon volumes, containers, and loads;

ii. Membrane filter assemblies shall be sterilized at the start of the first filtration series, either by autoclaving in accordance with (a)1i above, or by two minutes of exposure in an ultraviolet sterilizer unit. The laboratory shall not use the ultraviolet sterilizer unit if its use affects the validity of the results. The laboratory shall test the ultraviolet lamps quarterly with a light meter and a spread plate irradiation test. The laboratory shall not reuse a filtration unit without sterilizing it if 30 minutes or more has elapsed since the last sample was filtered; and

iii. If glassware is sterilized in a hot air oven, the temperature shall be held at 170 degrees Celsius for a minimum of two hours.

i. Has been tested by a certified environmental laboratory certified to perform the required chemical analysis for testing of the laboratory pure water; and

ii. Meets the requirements in Table 4.1 at N.J.A.C. 7:18-4.5(c)4.

i. Stock buffer solution shall be prepared in accordance with the DSAM or EPA Microbiological Methods, using laboratory pure water;

ii. Stock buffer shall be either autoclaved or filter-sterilized, and must be labeled, dated, and stored at one to five degrees Celsius;

iii. The stored buffer solution shall be free of turbidity; and

iv. Rinse and dilution water shall be prepared by adding 1.25 milliliters of stock buffer solution and five milliliters of magnesium chloride solution (81.1 grams of magnesium chloride hexahydrate) per liter of laboratory pure water, and the final pH shall be 7.2 +/- 0.1.

i. All media shall be prepared according to the procedures for media preparation set out in the DSAM. However, lactose broth shall not be used;

ii. Dehydrated media containers shall be kept tightly closed and stored in a cool, dry location, to prevent discoloration and caking. Laboratories shall not use discolored or caked dehydrated media;

iii. Dissolution of the media using laboratory pure water shall be completed before dispensing to culture tubes or bottles;

iv. The membrane filter broth and agar media shall be heated in a boiling water bath or they may be heated on a hot plate if constantly agitated until completely dissolved;

v. MF broths shall be stored and refrigerated no longer than 96 hours and poured MF agar plates shall be stored, refrigerated and used within two weeks;

vi. MPN media prepared in tubes with loose-fitting caps shall be used within one week, but if MPN media are refrigerated after sterilization, they shall be incubated overnight at 35 degrees Celsius to confirm usability, and tubes showing growth or gas bubbles shall be discarded;

vii. Media in screw cap containers may be held up to three months, provided that the media are stored in an enclosed area so that no light may enter and evaporation does not exceed 10 percent of the original volume; in addition, commercially prepared liquid and agar media supplies may be used; and

viii. Ampule media shall be stored at one to five degrees Celsius (34 to 41 degrees Fahrenheit), and storage time shall be limited to the manufacturer's expiration date.