Milk is a very useful product for human health, which is recommended for use at any age in the absence of contraindications to this. However, it should be noted that only the product that fully meets all the requirements of GOST and will not have any defects will be useful. We will talk about what milk defects exist later.
Requirements for milk in accordance with GOST
Any high-quality milk must fully comply with the requirements established by GOST. It states that this product is presented in the form of an opaque liquid, which in some cases may have slight greasy sludge (if the proportion of fat in the product is more than 4.7%).
As for the consistency, on the basis of the information contained in GOST R52054-2003, it should not only be liquid, but also non-viscous, but slightly viscous. Moreover, the mass should not contain pieces of fat and protein flakes.
GOST R 52054-2003 indicates that milk can have a smell and taste only that which is natural for such a product, the presence of other characteristics is not allowed. If milk belongs to the category of baked, it should have a pleasant creamy aftertaste, which can be slightly sweet.
GOST 31449-2013 also provides certain color characteristics that normal milk must meet that can have a beneficial effect on the human body. In accordance with them, normal milk should be white. In the event that the product is fat-free, the presence of a bluish tint is allowed, and if melted, then a creamy tone should be present in it.
GOST 31449-2013 establishes certain requirements in relation to physicochemical parameters. They established acceptable indicators of the mass fraction of fat, suitable for different degrees of fat content of the product relative to the acidity of the product, its density, as well as its temperature when leaving the enterprise.
Next, we consider in the most detailed way the main deviations inherent in this product, which are not allowed by any GOST - in production they are called defects.
Taste
GOST R 52054-2003 strictly spells out the taste characteristics that normal, suitable milk should have. It should be noted that taste defects are of bacterial origin - this means that taste deviations occur, as a rule, as a result of the intervention of harmful bacteria.
Milk that does not meet the standards presented in GOST may have a bitter, sour or rancid taste. Consider the main reasons for the formation of such deviations.
Milk can become rancid only as a result of prolonged storage of the product at low temperatures. Due to these conditions, bacteria are formed in the product that actively release the lipase enzyme, which breaks down fats.
In the event that the taste of milk is endowed with bitterness, you should be aware that the product became damaged as a result of prolonged storage at low temperature and in the absence of sanitation. So, as a result of this, putrefactive bacteria begin to form in the liquid, which in the process of their life destroy the proteins contained in the product, which makes it bitter. In order to prevent the manifestation of such a defect, it is necessary to provide sanitary conditions for the storage of bacterially contaminated milk.
The presence of an acidic taste in milk suggests that during its curing and during primary processing the standard sanitary norms were not observed, which created favorable conditions for the multiplication of bacteria that break down milk sugar, which ultimately leads to a quick souring.
Other flavors
Milk is a product that may have other flavors that were acquired during its processing and storage. As practice shows, the most common problems are the presence of a metallic or soapy taste. How to remove the taste of milk, unconventional for a normal product? Practice shows that it is possible to eliminate these deviations only by removing the main causes of the problem. If the taste of metal is characteristic of milk, it is necessary to exclude the storage of the product in poorly tinned or, worse, in rusty dishes. Also, the cause of the manifestation of a metallic taste in milk can be the regular watering of animals with water containing a large amount of iron oxides.
If milk has a soapy taste, then you should pay attention to the conditions under which it is stored after the milking process, because the main reason for this phenomenon is the content of the product, which has not undergone the cooling process, in a closed metal dish.
Ductility
Another type of bacterial malformation of milk is its stickiness. This phenomenon is caused by the presence of lactic acid type bacteria in the product, which during the course of their life release mucus.
Practice shows that milk having this type of vice has a sticky consistency, and it also has a sour taste.
How to avoid the formation of such a vice of milk? To do this, first of all, it is necessary to provide a full range of sanitary conditions for milking cows, and after it immediately cool the resulting product at an acceptable low temperature.
Color spots
The presence of colored spots in milk is another version of the defect, which belongs to the group of bacterial. It can occur only during prolonged storage of a product that, after being donated, has not been sufficiently cooled. What are these colored spots? This is the result of the activity of bacteria with a coloring pigment - it is they that emit colored particles, which subsequently form spots of different shades: red, blue, orange, etc. Specialists strongly do not recommend using such a product as food, as it harms human health.
In some cases, the presence of red spots is a manifestation of the presence of blood in the product, and this indicates that the udder of the cow is unhealthy. In this situation, there is only one solution: identify unhealthy cows and cure them.
Various spots can also be evidence that cows eat certain types of grass, incorporating coloring pigments.
Fermenting milk
When analyzing the quality of milk, attention is also drawn to whether there are signs of active fermentation in it. If there are any, then the product is considered unfit for consumption.
The presence of fermentation processes in the product is primarily due to the fact that its composition contains yeast or certain types of harmful bacteria, including E. coli, butyric acid and other types of microorganisms. The main signs of spoiled milk is the release of gases by the product, which are accompanied by yeast and alcohol seasonings.
In order to avoid the occurrence of such a vice, it is necessary first of all to comply with all sanitary standards when milking a cow and processing a product. You should also remove containers with milk from the barn in time - immediately after milking.
In order to avoid the formation of gases in milk, it is impossible to feed cows and to remove manure before milking.
Bad smell
The presence of an unpleasant smell of the product is another vice. What smells of milk that meets GOST standards? Its aroma is light, milky, with the presence of light creamy notes. If the product is characterized by a rotten aroma with an admixture of the traditional smell prevailing in the barn, then this is a significant deviation from the norm and a sign of a defect of physico-chemical origin.
How to remove odor from milk, uncharacteristic for the product? In order to avoid undesirable aromatic impurities in milk, it is necessary to eliminate the root cause that causes them. To do this, you need to regularly ventilate the barn, as well as store flasks with the prepared product under tightly closed lids. It is also important to remember that when ventilating before milking cows, drafts should not be allowed.
Rennet milk
Rennet lethargy of milk is another product defect that arises from the regular feeding of cows with feed containing inadequate amounts of calcium salts. This product is ideal for processing into canned food or butter, as well as into cottage cheese, but subject to the addition of a large amount of calcium chloride solution.
Rennet milk is a product that does not coagulate at all, or it appears, but very weakly.
Rennet milk is not recommended for use in its entirety. What is whole milk? This is a product whose constituent parts have not been altered artificially. In other words, the content of proteins, carbohydrates, as well as the fat content of the product remain at the level of those indicators that were in the product immediately after the milking process.
Greasy aftertaste
The presence of a greasy flavor in the product is another fairly common reason why milk does not comply with GOST. Its manifestation is caused by prolonged storage of the product, as well as the implementation of the process of its processing under the influence of direct sunlight.
In order to avoid such a phenomenon, experts in the field of agriculture and cow breeding strongly recommend that milk stores be built so that the windows of the buildings face north, and coolers are generally located as far as possible from them. Only in this way can the product be protected from sunlight, which will cause the formation of such a milk defect as a greasy flavor.
Curd consistency
What should be the consistency of milk provided for in accordance with GOST? As indicated above, a liquid consistency is considered normal when there are no lumps and flakes. Quite rarely, but there are situations when a product acquires a curdled consistency. The reason for the manifestation of this problem is the presence in the product of dairy microorganisms, which are characterized by the development of rennet. Another reason for the manifestation of the consistency of the consistency is the presence in the product of bacteria from the group of Escherichia coli, yeast or microorganisms, which form acid during their life. In some cases, the main cause of this phenomenon is mastitis, which manifests itself only in the case of accumulation of mastitis streptococcus in milk.
Water content of milk
Another variant of milk defect is the excessive water content of its consistency. The cause of this negative phenomenon can be a number of diseases, including catarrhal inflammation of the udder or tuberculosis. Also, the reason for this may be feeding the animal a large amount of watery food, as well as beets or bards. Often the cause of excessively liquid milk is the process of estrus in the cow.
Sometimes the cause of excessive milk fluid may be improper milk processing. In particular, watery mass is formed when the thawing of milk, frozen not using technology, or its dilution with water is carried out.