Overview

In Ontario, goat milk producers undergo routine regulatory sampling and testing of their bulk tank milk. The test results are monitored and tracked by the Ministry of Agriculture, Food and Rural Affairs.

Milk grading protects the quality and safety of the milk supply in Ontario. The grading is conducted by a trained and certified bulk tank milk grader (BTMG).

Before goat milk from an Ontario farm is transported to processors, the milk is graded in the bulk tank and a sample is collected for laboratory testing.

Milk graders follow procedures and regulatory requirements to ensure samples arrive at the laboratory in suitable condition for testing. Learn more about their responsibilities and how to become one.

Sample collection process

A bulk tank milk grader follows these steps to collect a sample.

1. Milk agitation

The milk grader ensures the milk in the bulk tank has been agitated for at least 2 minutes immediately before they collect a sample. This ensures the milk is completely mixed, so that the sample is representative of all the milk inside the tank.

A representative sample cannot be collected if there is evidence of milk freezing or the agitator is not functioning properly.

2. Grade by sight and smell

The milk grader looks at and smells the milk. They will reject it if:

  • there is evidence of foreign matter, such as straw or flies
  • it has an odour other than that of clean, fresh milk 


Rejected milk may not be used for human consumption and the producer must dispose of it in an environmentally responsible manner.

3. Collect sample

The milk grader uses an individually wrapped sterile straw (also called a “pipette”) to aseptically collect a milk sample from the bulk tank.

Milk graders keep their supply of straws clean and dry to prevent contaminating the sample.

Using a dipper

If the milk grader cannot reach the milk with a straw, they will use a clean, long-handled dipper provided by the producer.

The dipper must be made of stainless steel or smooth plastic. Dippers with rough welds, wood or tape may contaminate the sample and are not acceptable.

The producer must place the dipper in a freshly prepared sanitizer solution and make it available to the milk grader on milk collection day.

4. Seal the sample

Vial

The milk grader uses a sterile, sealed sample vial supplied by the University of Guelph's Agriculture and Food Laboratory to collect the sample. Empty vials are sealed and tamper-evident to ensure they are sterile until used.

After the milk grader collects the sample and snaps the lid closed, a locking tab ensures the vial remains sealed to avoid tampering during transit.

Label and tag

The milk grader affixes a label with the producer’s registration number to the sample lid.

If necessary, they use a buff tag to identify any problems at the farm on collection day that could affect the sample (such as an agitator not working, or a dipper not available). Tagging the sample lets the lab know that the sample is not representative of the milk in the tank and must not be tested for composition or quality.

The sample will still be available for inhibitor testing (such as antibiotics), and further grading if necessary.

5. Storage and transportation

The milk grader ensures the sample is kept between 0° and 4°C from the time it is collected until its delivery to a sample depot or the lab.

To maintain sample temperatures, milk graders transport samples in coolers fitted with plastic inserts that are filled with an ice-water mixture.

The cooler also contains:

  • a sample vial with water (referred to as a “water blank”) to allow the milk grader to easily monitor the cooler temperature using a hand-held thermometer inserted in the water vial
  • a time-temperature recording (TTR) device to record time and sample temperatures throughout transit to the lab

Laboratory delivery

Milk graders transport the samples in coolers directly to the lab, or to depot fridges where they are collected and transported to the lab.

When samples arrive at the lab, a lab technician downloads and reviews the temperature readings from the TTR to verify that samples have been maintained between 0°C and 4°C throughout their transport.

Lab staff also check the temperature of the water blank. Technicians cannot perform certain tests, such as bacteria testing, if sample temperatures have been below 0°C or over 4°C at any time.

Testing

The University of Guelph’s Agriculture and Food Laboratory conducts the sample testing, as approved by the Director under the Milk Act. It is an accredited lab, meaning that it must take extra steps to ensure the accuracy and repeatability of test results.

The samples are tested for:

  • bacteria levels, using a BactoScan™
  • presence of inhibitors, such as antibiotics
  • somatic cell count, which can indicate animal health and milk quality

Samples are also examined for their freezing point, which can indicate abnormalities such as added water.

Trained and experienced technicians document and validate sample handling and test methods and procedures. The lab technician will not test a sample if:

  • there is evidence of vial damage
  • the vial locking tab is not intact when it arrives at the lab

The lab will only test for bacteria in goat milk samples that are:

  • less than 48 hours old from time of collection at the farm
  • have been maintained between 0°C and 4°C since leaving the farm

Test results

The University of Guelph’s Agriculture and Food Laboratory reports the sample test results to the Ministry of Agriculture, Food and Rural Affairs’ Inspection Programs Unit. The ministry then communicates the results to producers.

The ministry tracks and reviews test results to determine when follow-up is needed. Ministry staff can help producers determine the cause of the problems if they have ongoing milk quality concerns.

Testing conducted by goat milk brokers

Some goat milk brokers conduct additional sample testing to proactively detect problems and promote high milk quality standards.

Brokers are responsible for reporting the test results directly to producers and the ministry.