University of KentuckyCollege of Agriculture
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Regulatory Services Milk Lab

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Laboratory Requirements

The primary goal of Regulatory Services’ Milk Program is to provide a fair and equitable marketplace environment for all producers, processors and handlers involved in Kentucky’s dairy industry. A key component in the milk marketing system is laboratory testing. Observing proper procedures in laboratories is critical to ensure proper producer payments and to ensure accurate billing when milk moves between processors and/or handlers. Receiving location laboratories as well as all labs that potentially test Kentucky producer’s samples for payment are required to be licensed by Regulatory Services. Likewise, lab personnel who actually perform these tests are licensed too. There are a number of licensed laboratories that do not test milk for payment purposes. These labs choose to be licensed as a means to establish credibility and to assist in their overall quality control programs.

License applications can be obtained by contacting Regulatory Services. A new tester will be issued a 120 day Temporary License to Test Milk. This allows the new tester an adequate amount of time to train and to become knowledgeable of proper lab procedures. Prior to the expiration of the temporary license, the tester will take a written examination. Upon scoring a minimum of 70% on the exam and demonstrating appropriate lab techniques to a Regulatory Services representative, a License to Test Milk will be issued.

Basic Lab Requirements

Licensed laboratories are subject to have their facilities, equipment and procedures evaluated by Regulatory Services during normal business hours. Labs that are not open during customary business hours are required to provide Regulatory Services with an advanced schedule. Inspections are usually conducted at times that will cause the least disruption to a lab’s normal activities. During inspection visits, lab personnel are encouraged to utilize their normal, everyday procedures. Do not employ additional procedures or steps just because a visitor is present.

In addition, Regulatory Services will provide check samples to licensed laboratories for test result comparisons and monitoring purposes. A licensed tester at the laboratory shall test each sample for the appropriate components using an approved method for which both the tester and lab is licensed. The results are to be returned to Regulatory Services within three (3) working days of receipt of the samples. A comparison report will then be provided to the laboratory. The licensed laboratory is also responsible for returning all check sample shipping containers and equipment to Regulatory Services.

Key Areas of Consideration for Laboratories and Testers

  • Sample storage: A refrigerator or other appropriate storage area should be available to maintain sample temperatures in a temperature range of 0.5-4.40C (33-40 F). Milk samples should always be stored in a manner to protect the sample’s integrity (prevent leakers and cracked vials). The sample storage area is required to be monitored on a daily basis. This can be accomplished with a recording device or a licensed person maintaining a daily log.
  • Samples: Producer samples tested for components are to be analyzed within 72 hours from the time of procurement (unless samples are preserved). Grade A producers are required to have a minimum of five (5) actual tests per month. Manufacturing grade producers are required to have a minimum of three (3) actual tests per fifteen (15) day period.
  • Records and documentation: Labs testing components for pay purposes should have an established, written policy concerning “wild tests”. “Wild tests” should not be used for pay purposes. Additionally, all lab records should be kept on file for at least two years. These include:
    • Equipment records: For electronic equipment, this includes records for maintenance, daily performance checks, and calibrations.
    • Test records: Actual records of tests used for pay purposes.
    • Special test records: These include retests and other special tests, and should be specifically identified.

Lab procedures, facilities and equipment: It is important that all testing be performed in accordance with approved procedures. Currently the references for these procedures are "Official Methods of Analysis of AOAC International", Volume II, Chapter 33, 17th Edition, 2000; and "Standard Methods for the Examination of Dairy Products", 16th Edition, 1992. Procedures found within these documents have undergone rigorous evaluations and are recognized to be scientifically sound.

“Standard Methods” also outlines the requirements for laboratory facilities and equipment. The laboratory area should generally be designated solely for analytical and related activities. Proper attention should be given to items such as ventilation, lighting, work and storage space, utilities, and cleanliness. A sacrifice relating to any of these items can increase the potential for problems in areas such as analytical error and lab safety.

Lab equipment should be kept in good repair and if appropriate, be monitored with a maintenance schedule. It is important that equipment be used only for purposes for which it was designed. Only properly trained personnel should use highly specialized equipment and instruments.


If you are interested in obtaining additional related information or a lab handbook, contact the Milk Program by email or at (859) 257-2785.