The Department of Veterinary Services has a mandate to ensure that milk and milk products destined for the consumer, are derived from a healthy national dairy herd. The Division of Field Services conducts surveillance and monitoring of the animals and cleanliness of the farms in collaboration with the Department of Animal Production`s Dairy Section. The milk at various levels of processing is also monitored for its quality and health status. The Dairy hygiene section of the veterinary laboratory tests samples to monitor: udder health, standard of hygiene associated with milking, efficiency of heat treatment (pasteurization) and to check for certain disease conditions such as brucellosis. The quality of milk and milk products is also tested according to national and  international standards.

What type of samples can the lab receive?

Raw milk, pasteurized milk, ultra high temperature treated (UHT) milk and other dairy products samples are received from the whole country. These may be sent by extension officers, other government departments, milk processors and directly by farmers. farmers may be interested in the health status of individual animal or entire herd.

What are the various tests available?

Tests are performed on the different samples submitted according to the clients request. This may be to check for fitness for human consumption or herd health monitoring. The following tests can be carried out: 

Raw milk (direct from the farm)  

 1. Milk quality tests

Presence of added water

To determine and detect amount of water has been added to milk. This is a quality test

      Milk composition

To determine the amount of fat or protein is in the milk as well as other components of milk (total solids, solid non fat, lactose, casein, free fatty acids and density). 

 2. Herd health tests

Milk can be tested for presence of brucella antibodies which indicates a possibility of brucellosis infection in the herd. This disease is transmissible to man.

Mastitis is a sign of an unhelathy udder. An unhealthy udder will release more cells than normal. This condition is monitored by testing for level of somatic cells in the milk. If these cells are over a certain number in the milk it shows that the cows could be having sub clinical mastitis and further tests will be done to check  for causes of the infection and further the type of treatment remedies that can be used. The type of treatment available comes in options and can assist the farmer to select one taking into consideration the milk withdrawal periods.

 3. Inhibitory substances

No food item is expected to have veterinary drug residues. Veterinary drug residues tests are performed  to check for inhibitory substances in the milk such as antibiotics which may have undesirable effects on consumers.

4. On Farm Hygiene

There are various tests that can be done on milk which to give an idea of the standard of hygiene at the farm. If these tests fail it shows that hygiene practices are not well carried out when milking. These include coliforms, resazurin and acidity tests.

Pasteurized milk (fresh milk in shops)

Efficiency of pasteurization

These are tests on milk to check if pasteurized milk has been heated enough to kill all bacteria that may be harmful when consumed and the general hygiene of the pasteurising plant.

Added water is also checked in pasteurized milk as well as drug residues, fat and protein content.

UHT milk (Long life milk)

Total spores

Other dairy products (yoghurts, sour milk/madila, juices, cheeses etc)

Determination of Shelf life

These products are tested for how long they can stay before they go off (shelflife).

Contamination

Yoghurts have fruit pieces added to them therefore tests are run to check if fruits used had no harmful organisms, and checks for any other contaminats that might have occured during packaging.

What is the cost of each tests?

All these tests are done at no cost to the dairy farmers in Botswana as Government supports to the infant dairy industry. Services are provided to individual local dairy farmers, dairy processors, dairy extension staff and other food control laboratories including Botswana Bureau of Standards (BOBS).

Summary of tests that can be requested for different samples