|
|
|
|
|
|
The dairy farm
Milk processing starts at the dairy farm. The cows are milked and the milk is transported to the dairy where it is processed into various products.
Dairy cows The dairy farmer selects breeds of cattle that are most suitable for producing milk. Some breeds give large quantities of milk, and others give milk that contain a high percentage of butterfat. There are many dairy cattle in South Africa including the Holstein, Jersey, Ayrshire and Guernsey breeds.
|  |
Douglasdale milk is free of rBST growth hormone and preservatives!
How to keep milk fresher for longer
- Minimise the milk's exposure to sunlight as this destroys the riboflavin content (Vitamin B12).
- Refrigerate the milk upright below 5 degrees centigrade
- Store the milk in a closed container; otherwise it is likely to absorb the flavour of other foodstuff stored in the refrigerator.
Douglasdale Dairy milk is suitable for home freezing
Freeze on the day of purchasing and use within one month from date of purchase by defrosting in the fridge for a minimum of 8 hours. Once defrosted shake thoroughly and use within three days of thawing.
HACCP Certification
Douglasdale Dairy is proud to be one of the first Gauteng based fresh milk dairies to achieve international Food Safety Standard, HACCP (Hazard Analysis and Critical Control Point) certification. |
|
Today's dairy farmer must have a thorough knowledge of cattle breeding, feeding, milk production and modern milking techniques in order to produce a high quality product of a regular quantity throughout the year. The quality and quantity of milk produced by the cow depends on the fodder that it eats. This is usually silage, oats, bean hay, maize stalks, lucern, cottonseed, seedcake or dairy meal. Cattlefeed with a high nutritional value improves the quality of the milk. |
|
|
Milking
In the past cows were milked by hand, but today milking machines are used. These reduce milking time and are more hygienic. In the milking parlour on the farm each teat is tested for mastitis. Mastitis is an infection of the udder, and milk from a cow infected with mastitis is not suitable for human consumption. If the test shows that the udder is healthy, the cow's teats are connected to the milking machine by four rubber suckers. The milk flows through the tubes across very fine filters that remove any impurities, and then it is pumped into stainless steel tanks.
Immediately after milking, the milk, which is at body temperature, must be cooled to below 5° C to slow down the reproduction rate of the bacteria. The rate at which bacteria which are responsible for the spoiling of milk reproduce, dramatically accelerates at temperatures above 5° C. Consequently, milk can spoil easily and will go sour in a short time if left at room temperature. |
|
The milk is collected from the farm in large insulated road tankers and taken to the dairy. Before the milk is pumped into the road tanker at the farm, samples of the milk are taken to be tested. The milk is smelt and tasted to check whether it is sour, and also pH tested to measure the acidity of the milk. If the milk passes these tests, it is pumped into the road tanker and hauled to the dairy. |
|
Douglasdale tests the milk at every stage from delivery by the road tanker to packaging for sale to shops and consumers.
When the road tankers arrive at Douglasdale, the milk in the tanker is tested for antibiotics, quality levels and water content. The samples collected at the farm are also tested in Douglasdale's own laboratory for butterfat, protein, lactose and added water. If all the samples are approved, the milk is pumped from the road tanker into Douglasdale's large milk silos. While it is being pumped, a drip sample is taken and then a further test is done for water and butterfat content. The water content test ensures that no water has been added to the milk during transport and the butterfat test provides the actual butterfat content of the entire tanker.
Antibiotic testing: Each compartment is checked for antibiotics. If positive, it is rejected. This is important because some people can have sever allergic reactions to antibiotics.
Water content: Milk consists of 88% water and 12% solid constituents. A water content test measures the freezing point of the milk. If the percentage of water is greater than 88% then water has been added and the freezing point changes. By measuring the freezing point, it is possible to predict exactly how much water has been added. No milk will be accepted with added water.
Butterfat content: The amount of butterfat in the milk is important because this is what gives milk its creamy taste.
Freshness and keeping quality: The raw milk is also tested for freshness and keeping quality, and for this a test called the Resazurin or dye reduction test is used. Resazurin is a dye that reacts to the chemical changes in milk caused by the bacteria that make the milk go sour. The dye changes colour and is a measure of the total number of living bacteria in the milk.
Other bacterial tests, including the test for coliform bacteria, are performed on Douglasdale's processed milk to ensure that the milk is of the best quality before being distributed to the public.
|
|
|
Douglasdale processes the milk into different products and in so doing ensures that its products are healthy and nutritious. A whole range of modern processing equipment is used. |
| The bactofuge (bacteria-removing centrifuge) The bactofuge removes heat-resistant and other bacteria from the milk prior to pasteurisation. This includes the spores of heat resistant bacteria such as Clostridia sp. and Bacillus sp. which can remain active in the milk after pasteurisation. By using a bactofuge, Douglasdale improves the quality of the milk it supplies. It has a longer shelf life, better taste, lower bacterial cell counts and reduced impurities. |
|
|
Pasteurisation
Milk is a favourable breeding ground for bacteria which is pasteurised to destroy pathogenic organisms. This is not complete sterilisation but a heat treatment in which the temperature is just high enough to destroy bacteria without affecting the taste. The milk is pumped through a pasteuriser which consists of many stainless steel plates that are clamped together. A plate pasteuriser employs a regenerative process to improve energy efficiency, which means that the hot milk leaving the pasteurisation process is used to heat the cold milk entering the pasteurisation process. The incoming milk is finally raised to pasteurisation temperature by hot water and the milk leaving the pasteurisation process is finally cooled to 4 °C using chilled water. Pasteurisation does not have any significant effect on the nutritional value of milk. |
Centrifugal separator
The centrifuge is a machine used for separating and removing cream from milk. Its operation is based on the fact that skim milk (milk with virtually no butterfat) is heavier than cream. The separator consists of a centrifuge in the form of a rapidly revolving bowl containing a set of disks. As the milk enters the bowl, it is distributed to the disks through a series of openings. Thin films of milk are forced between the disks and the heavier skim milk is thrown to the outer edge of the bowl and led off through an opening. The cream concentrates in the interior and moves up to the cream outlet near the centre of the bowl. |
|
|
The homogeniser
The purpose of the homogeniser is to spread the butterfat evenly throughout the milk. If this is not done, the butterfat due to its lower density will rise to the top of the container and form a creamy layer. In the homogeniser, the milk is placed under high pressures causing the fat globules to break down and become evenly distributed throughout the milk. Homogenised milk is tastier, whiter and easier to digest. It also allows Douglasdale milk to be frozen. |
|
When the milk and milk products have been processed, they are filled into containers of different sizes for sale to consumers.
Each container is marked with an expiry date so that the consumer knows how fresh the product is. Milk left to warm and remain at room temperature will sour long before the expiry date while Douglasdale milk kept below 5° C will remain fresh well beyond the expiry date on the package. |
 |
|
|
| |
