The quality of milk is determined by the following indicators: taste, color, smell, the presence of impurities, preservatives, vegetable fats. High-quality milk must comply with the parameters of GOST 13277-79.
Milk is one of the most important foods in the human diet. The quality of milk on store shelves is regulated by GOST 13277-79, and the examination of the product is carried out in laboratory conditions for organoleptic and physicochemical parameters. However, even at home, the buyer can check whether he has purchased a quality product.
How to check milk quality indicators
The organoleptic quality indicators include the appearance, taste and smell of the product. Fresh, undiluted milk has a delicate, rich taste and a pronounced milky aroma. Milk should not be bitter, sour or salty - this indicates that the product is stale or obtained from a sick animal. A burnt smell is unacceptable, since it means a violation of the temperature regime during milk processing.
The most common cheat when selling homemade milk is dilution with water. It is not so difficult to identify it: it is enough to put a drop of milk on some surface and observe it. Undiluted milk retains its shape well, so the drop does not spread for a long time.
Diluted skim milk has a watery taste and a bluish tinge. If it is not possible to determine the wholeness of milk by eye, you can use a hydrometer: the density of the product must be at least 1.027 g / cc.
How do various impurities, preservatives and vegetable fats affect the quality of milk?
The presence of impurities unambiguously degrades the quality of the product. Additives such as flour, lime, chalk, gypsum, boric acid and salicylic acid can be used to hide milk imperfections and increase its shelf life.
The presence of starch and flour can be identified by the characteristic mealy flavor. Acids are detected using a litmus test, which turns red in an acidic environment. To find out about the presence of lime, soda or chalk in milk, you can use a citric acid solution. Acid is dropped onto paper soaked in milk and the reaction is monitored. The hissing and the formation of bubbles suggests that it has not been without impurities.
Milk with a high fat content should be chosen with particular care. Many unscrupulous manufacturers use vegetable fats to increase the fat content, and not cream, as it should be according to GOST. Unfortunately, the presence of herbal supplements can only be determined in the laboratory, so when buying fatty milk you will have to rely on the manufacturer's reputation.
