The density of whole milk is one of the most important quality parameters of this product. All substances are balanced in such a way that milk has become a source of essential minerals, vitamins and a complex of easily digestible proteins for humanity for thousands of years. The density of milk determines the naturalness of the product and its nutritional value.
What is the density of milk and its norm
Density is the amount of milk (mass) at +20 ° C, equivalent to the amount of distilled water, with a temperature of +4 ° C, with equal volumes of liquids.
Milk is a heterogeneous liquid consisting of various components; the product certainly contains:
- protein;
- milk fat;
- lactose;
- water;
- complex of mineral salts.
Increasing the content of protein, lactose and mineral salts in the liquid increases the density of the product. High fat content reduces the indicator. Skim milk will have a higher rate. The normal specific gravity of whole raw milk is 1.028. It is measured with a hydrometer. Values may fluctuate slightly.
| Milk product | Density kg/m3 |
| Whole | 1,0127-1,032 |
| Prefabricated | 1,028-1,030 |
| Low fat | 1,033-1,035 |
| Colostrum | 1,038-1,040 |
| Cream | 1,005-1,020 |
Adding 10% water to whole milk reduces the indicator by approximately 3 kilograms per cubic centimeter. If the density is below 1.0127, there is water in the milk; a reading of exactly 1.0127 is suspicious; 1.0128 means a quality product is being analyzed.
Factors affecting density
It increases when water is added to milk and decreases when skim milk is added to it. But even for a conscientious owner, indicators may change for a number of reasons;
- seasonal fluctuations in fat content;
- feeding characteristics of the livestock;
- breed of livestock;
- depends on the lactation period (in the first months after calving, the fat content of cow's milk is higher);
- animal health.
To bring the indicator to the average value, collected milk is measured (from different cows, with different percentages of fat content).
Is it possible to increase the indicators
They can be increased by observing the regime for keeping animals. Cows should be examined regularly by a veterinarian. It is necessary to ensure that animals do not suffer from mastitis or diseases of the gastrointestinal tract. Be sure to monitor calving cows.
Milk from sick animals is checked additionally; it is usually discarded and not sold or processed.
Pedigree livestock is capable of producing a high-quality product. Dairy animals provide an increased amount of protein and minerals in milk compared to other types of cattle. The feed requires mineral supplements and vitamins. Animals are provided with high-quality hay, vegetables, roughage to improve digestion in winter, and are grazed in summer. Careful selection of pasture affects the quality of the product.
Regular cleaning of the barn, changing bedding, treating drinking bowls and feeders prevent the development of dangerous diseases in cows.
The complex of these measures allows you to increase the amount of protein, mineral salts, and therefore the quality and density of the product.
It is necessary to ensure that water does not enter the product during milking and storage of products. Immediately after milking, the indicator will be higher, since milk fat is still evenly distributed in the product. After storage, when it rises to the surface, the density indicator will decrease.
Measurement methods
Large farms have equipped quality control laboratories. To measure the density, whole milk is poured into the measuring cylinder to half or 2/3 of the volume at a temperature of +20 °C. The hydrometer is immersed in it. The indicator is recorded.
Important: for accuracy, take at least 2 measurements and calculate the average value.
There are no laboratories on the private farmstead; the quality and density of milk is checked as follows:
- A few drops of milk are added to a container with water; if they are immersed in water, gradually dissolving, the product is of high quality, the milk in which water has entered spreads like a film over the surface.
- Milk is mixed with alcohol in a ratio of 1:2. A quality product will curl into flakes. In diluted milk with low density, flakes do not form for a long time.
Simple methods allow you to determine the density and quality of milk. You can also find it out when purchasing at the market or from an unfamiliar manufacturer. This is one of the most important quality parameters of the product. It must be measured when milk is sent for sale or further processing.
