N.J. Admin. Code § 7:18-4.4

Current through Register Vol. 56, No. 21, November 4, 2024

Section 7:18-4.4 - Requirements for general environmental laboratory practices

(a) A laboratory performing microbiological analysis shall practice and meet the requirements listed in (a)1 through 4 below.

1. The laboratory shall follow sterilization procedures meeting the following requirements:

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;

Material

Time (Minutes)

Membrane filters and pads	10
Carbohydrate-containing media (lauryl tryptose,	12-15
brilliant green lactose bile broth, etc.)
Contaminated materials and discarded tests	30
Membrane filter assemblies (wrapped), sample	15
collection bottles (empty), individual glassware
items
Rinse water	15
Dilution water blanks	15

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.

2. The laboratory shall use only laboratory pure water that:

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 7:18-4.5(c)4.

3. The laboratory shall use only rinse water and dilution water that meets the following requirements:

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.

4. The laboratory shall use only media that is prepared and stored in accordance with the following requirements:

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.

N.J. Admin. Code § 7:18-4.4

Amended by R.1997 d.192, effective 5/19/1997.
See: 28 New Jersey Register 4149(a), 29 New Jersey Register 2275(a).
In (a)3iv, inserted "(81.1 grams of magnesium chloride hexahydrate)".