Section 512.2 - Character of Work and Tolerances(a) "Accuracy" means the degree of agreement of individual measurements with an accepted reference value. The accepted reference value shall be the analytical result made by the Department. "Precision" means the degree of mutual agreement among individual measurements made under prescribed-like conditions.(b) After notifying the management of any milk distributor, milk processor, dairy association, or commercial testing laboratory, the Department may obtain samples of any milk or cream previously tested by a licensed tester for the payment of any milk or cream or component of milk or cream. These samples may be tested in the Department's dairy chemistry laboratory to determine the accuracy of the licensed tester's work. The Department may request that the licensed tester retest the sample at the original testing facility by the same method as the sample was originally run, to determine the precision of the tester's work.(c) Persons making milk component tests by any approved or final action testing methods for payment purposes shall be able to demonstrate a capability to reproduce their own original tests and be able to produce work comparable to official final action tests from duplicate samples tested by the Department's dairy chemistry laboratory within the limits outlined in subsection (e) of this section.(d) Where analysis of milk components for payment purposes are made by infrared instrumentation, the Department will provide calibration samples to laboratories at a frequency established by mutual agreement but no less than that recommended in the instruction manual of the manufacturer of the instrument. The laboratory must demonstrate that they meet the required precision and accuracy as outlined in subsection (e) of this section.(e)ACCURACY AND PRECISION OF MILK TESTS BETWEEN RETESTS AND/OR OFFICIAL LABORATORY TESTS
| | Accuracy | | | Precision |
| | Mean Difference | | Standard Deviation of the Difference (SDD) | Maximum Difference between original test & retest |
| 5-8 | 9-16 | | | | |
| Component | Tests | Tests | | | | |
| ± | ± | | | | |
| % Milk Fat | 0.04 | 0.03 | 0.05 | 0.06 | |
| % Total Solids | 0.07 | 0.05 | 0.08 | 0.12 | |
| % Solids Not Fat | 0.07 | 0.05 | 0.08 | 0.12 | |
| % Protein | 0.05 | 0.04 | 0.06 | 0.05 | |
| % Lactose | 0.05 | 0.04 | 0.06 | 0.07 | |
(f) When a retest on individual sample of milk exceeds the maximum difference in subsection (e) of this section, the retest shall be used, unless the sample is deemed to be unsuitable for testing due to oiling off, churning, water in the sample, or other sample anomaly, in which case the application of the averaging procedures in section 525(e) of this article, shall be used. A test on an individual sample of milk that exceeds the previous test average (minimum of 4 samples to arrive at previous test average) by more than 0.2 % for any component will automatically trigger a retest.(g) When a retest on an individual sample of milk does not exceed the maximum difference allowed in subsection (e) of this section the original test must be used as the basis for payment, and the original test will be reported on the original test sheet, with an explanation of the retest.(h) When a retest on a sample of cream amounts to seventy-five hundredths of one percent (0.75%) or greater, the retest shall be used, unless the sample is deemed to be unsuitable for testing due to oiling off, churning, water in the sample, or other sample anomaly, in which case the application of the averaging procedures in section 525(e) of this article shall be used.(i) The Department may check the accuracy and precision of licensed testers' work by unannounced inspections. The Department will review the work of licensed testers whenever a complaint is made regarding the accuracy and precision of their work.Cal. Code Regs. Tit. 3, § 512.2
1. New section filed 10-19-79; designated effective 1-1-80 (Register 79, No. 42).
2. Editorial correction of Example 2 (Register 80, No. 6).
3. Amendment filed 2-15-2007; operative 3-17-2007 (Register 2007, No. 7). Note: Authority cited: Section 407, Food and Agricultural Code. Reference: Sections 32921 and 34261.5, Food and Agricultural Code.
1. New section filed 10-19-79; designated effective 1-1-80 (Register 79, No. 42).
2. Editorial correction of Example 2 (Register 80, No. 6).
3. Amendment filed 2-15-2007; operative 3-17-2007 (Register 2007, No. 7).