Regulating Sampling and Testing under the Raw Goat Milk Quality Program

Goat milk sample collection, transport, storage and testing all have the potential to affect quality results. That's why various checks and balances have been set up throughout the milk sampling system to ensure the chain of custody is maintained and that samples arrive at the laboratory in acceptable condition.

Bulk Tank Milk Graders (BTMGs), more commonly referred to as "drivers", have been trained and certified for their duties associated with collection of milk at the farm including proper collection and storage of milk samples. This includes ensuring that a representative sample of raw milk is carefully collected from each individual bulk tank, accurately recorded and delivered to a depot under refrigerated conditions.

Requirements for taking and transporting milk samples

  • Bulk tanks must be agitated for a minimum of two minutes prior to the sample collection. This is to ensure that the sample is a representative one. Therefore it is important that milk is not frozen and that the agitator is working.
  • The BTMG takes the temperature of the milk and records it. Milk in the bulk tank should be maintained between 1 and 4°C.
  • Sterile, sealed, tamper-proof sample vials supplied by the University of Guelph's Agriculture and Food Laboratory are used.
  • Individually wrapped sterile straws are used to fill sample vials. The supply of straws is kept clean and dry by the BTMG in order to prevent contamination of the sample.
  • It is the producer's responsibility to provide a clean, long handled dipper if it is needed to reach the milk for sampling. Stainless steel or smooth plastic construction are required. Rough welds, wood and tape are not acceptable as they may contribute to contamination of the sample. The dipper should be placed in a freshly prepared sanitizer solution and available to the BTMG on pickup day.
  • If there happens to be a problem at the farm on collection day that will affect the sample (such as an agitator not working, or a dipper not available), the BTMG is still required to collect a sample. However, the BTMG will tag the sample to alert the lab that it is not representative of the milk in the tank and therefore should not be tested for composition or quality. The sample will still be available for inhibitor testing and further grading.
  • To maintain sample temperature between 1°C and 4°C, BTMGs are required to transport samples in coolers fitted with plastic inserts that are filled with an ice water mixture.
  • A sample vial containing water is kept in the insert at all times so the BTMG can easily monitor the cooler temperature with a hand held thermometer.
  • Sample coolers are also equipped with time temperature recording devices known as I-buttons. These devices alert the laboratory if the samples have not been kept at the appropriate temperature.

Delivery of samples to the laboratory

Goat milk marketers have arrangements with private couriers to transport sample coolers to University of Guelph's Agriculture and Food Laboratory. When samples arrive at the lab, temperature readings from the I-buttons are downloaded and checked by lab technicians to verify that samples have been maintained between 1° and 4°C. Lab staff also check the temperature of the water blank vial. Quality testing is not performed if sample temperatures have, at any time, been over 4°C.

Testing by an accredited laboratory

University of Guelph's Agriculture and Food Laboratory (AFL) is an accredited lab, meaning that it must take extra steps to ensure the accuracy and repeatability of test results. This includes submitting to routine third party audits. Sample handling and test methods and procedures are documented and validated by trained and experienced technicians. Only goat milk samples that are less than 48 hours old from point of collection at the farm, and maintained between 1 and 4°C, can be tested for bacteria at the laboratory. Samples that are older than 48 hours, or that have not been kept cold, are not tested since their results may no longer accurately reflect the quality of the milk that was in the bulk tank.

Monthly testing of goat milk producer samples is conducted by the Dairy Food Safety Program of the Ontario Ministry of Agriculture and Food and Ministry of Rural Affairs at the University of Guelph's AFL. Samples are tested for bacteria levels (using the bactoscan), the presence of inhibitors (such as antibiotics), somatic cells and abnormalities (such as added water).

Reporting of Results

Sample test results are electronically transferred to the Dairy Food Safety Program and once a month reports are mailed out to producers. Test results are also tracked and reviewed for trends. Individual producers experiencing on-going quality problems are identified and offered assistance in detecting problems. Province-wide data is also monitored to detect trends in milk quality. Goat milk brokers may also conduct supplementary sample testing to proactively detect problems and promote high milk quality standards.

The integrity of the goat milk sampling system rests in the hands of producers, BTMGs, temperature recording technology and qualified lab technicians. All are doing their part to ensure high-quality goat milk and fair compensation for producers.


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca
Author: OMAFRA Staff
Creation Date: 6 January 2014
Last Reviewed: 6 January 2014