N.J. Stat. § 4:12-41.6
Any person purchasing milk or cream and paying for the same on the basis of the percentage of butter fat therein shall take and retain on his premises a representative part of each lot of milk purchased. The representative parts taken from the several lots of milk purchased from any one producer shall be combined into a composite sample. The composite sample together with a preservative approved by the director shall be placed in clean dry bottles of approved design. Such composite sample shall be plainly marked with the name or number of the producer represented and shall be of such size that the residue for check testing shall be sufficient to make two additional Babcock tests. Protection shall be provided against extremes of temperature and the entrance or loss of moisture, and at all times, except the interval during which milk or cream to be sampled is being received, said composite samples must be stored below fifty-five degrees Fahrenheit. The licensed sampler shall be responsible for the preparation and storage of such composite samples at all times except when they are being tested by the licensed tester.
Before a portion of a composite sample shall be taken for testing the contents of the container from which it is drawn shall be so treated that the butter fat is dispersed uniformly throughout the sample. Said composite sample shall cover a period of not over sixteen days and shall be tested within two days following the close of the period covered by such sample, and the producer represented by said composite sample shall be furnished a written or printed statement of the result thereof within four days after the day upon which the test was performed; said statement shall specify the period covered by the composite sample, and the record of daily deliveries specified in section five may be made a portion of the statement.
After such composite samples have been tested they shall be held intact, properly refrigerated and in a condition suitable for check testing, until the close of the second subsequent test period, and the director shall have the authority to examine and analyze such composite samples for the purpose of determining whether the percentages of butter fat have been correctly reported.
N.J.S. § 4:12-41.6