California Code of Regulations
Title 3 - Food and Agriculture
Division 2 - Animal Industry
Chapter 1 - Dairies
Article 14 - Official and Approved Testing Methods and Protocols
Section 513.5 - Operation of Infrared Instruments

(1) Persons testing raw milk by means of IR instrumentation shall hold a tester's license for IR and work under the supervision of personnel also licensed for IR testing, and responsible for all aspects of component payment testing at the facility.

(2) Each day the IR instrument is used, a check (pilot) sample warmed according to section 15.121 of the 17th Edition of Standard Methods for the Examination of Dairy Products, which is incorporated by reference, with the temperature verified and recorded prior to testing, shall be analyzed at start-up and once every hour thereafter. The pilot sample can be a commercially prepared pilot sample, UHT whole milk, pasteurized whole milk, or raw milk or similar matrix. The pilot sample shall be handled, prepared, and tested in the same manner as producer payment samples. The pilot sample component values will be determined by averaging several instrument readings, after having cleaned and zeroed the instrument. The average instrument readings for each component will be used as the baseline to compare the daily start-up and hourly pilot samples. The results shall be recorded in the permanent log book, in accordance with subsection (a)(5). The component values on the pilot samples shall be less than or equal to 0.04% of the original base line values. If any component value on a pilot sample exceeds the original base line value by more than 0.04%, the instrument shall be cleaned and zeroed, and a fresh pilot sample shall be run. If any of the pilot sample components still deviate from the baseline values by more than 0.04% the instrument will be considered to be malfunctioning, and all payment samples analyzed since the last acceptable pilot sample shall have their results reported using the averaging procedures outlined in section 525(e) of this article. In the event of instrument malfunction further testing must be done by alternate official final action methods, or acceptable methods of comparable accuracy. If the laboratory cannot perform the above methods, payment samples must be sent to another payment laboratory for analysis. The laboratory management shall submit a letter to the Department's Milk and Dairy Food Safety Branch identifying the alternate official final action methods and/or alternate laboratory that shall be used to analyze payment samples in the event of instrument malfunction, and update the letter as circumstances change.

(3) Samples of raw milk which are high in acidity, coagulated, or churned may not be tested by IR.

(4) If at any time the tester licensed to make milk component determinations by IR has reason to believe the results obtained are biased or inaccurate, all further testing must be done by alternate official final action methods listed in Food and Agricultural Code section 32921, or by acceptable methods of comparable accuracy, or the samples shall be tested by another payment laboratory until the bias is eliminated.

(5) The recommendations provided in the Instruction Manual of the manufacturer for calibration, sample preparation, operation, routine maintenance, daily instrument checks, and cleaning shall be followed, unless otherwise instructed in writing by a representative of the Department. A permanent log book shall be maintained that records the results of all pilot samples, as well as information pertaining to any adjustments made to the instrument (i.e. maintenance, calibration changes, daily instrument checks, and any other work done on the instrument). The log book shall be available for review by the Department upon request.

(6) The volume of the test portion shall be sufficient to make an original test and a retest. This volume may vary by instrument depending on the individual instrument volume uptake settings.

(7) The power input to the IR instrument shall be standardized by a constant voltage regulator.

(8) The IR instrument must be operated in an air-conditioned room where the temperature does not exceed 80°F.