- How to check the quality of milk. Quality control of milk at home
How to check the quality of milk. Quality control of milk at home
To check the quality of milk at home. It does not need to perform complex laboratory research, it is enough that there is always at hand.
milkmilk diluteddiluted waterlitmus paperdrop milkfilter paper
It is likely that not every home will have acid-base indicator paper, but having to check the quality of food, it can be easily purchased at the pharmacy.
So, strips of litmus paper are available. What's next? And then it is necessary to moisten one strip of indicator paper in brought from the store or market milk, wait 1-2 minutes and carefully consider a strip of litmus paper.
Coloration of litmus paper into blue color will indicate the presence in milk of soda or other alkali, red litmus paper would react to acidic environment resulting from adding the milk, bleach-based acids. If the color of the litmus paper strips has not changed, can quietly rejoice soda, boric and salicylic acid in the milk is purchased by you, no one added.
The presence of starch, which is added to the milk to give it density, can be quickly and easily identified using ordinary iodine from a home kit. In a small amount of milk should drip a few drops of an alcoholic solution of iodine.
If the milk will turn blue, therefore it mixed with starch, and a yellowish-orange color will indicate its absence in milk.
With alcohol can accurately determine if the milk diluted with water if to 1 part milk add 2 parts alcohol, and then the resulting mixture was actively stirred in for 1 minute.
When you are finished stirring, you must immediately pour the mixture of milk and alcohol in a bowl or saucer, carefully watching the state of the mixture locking time after which it will be flakes of white.
Rapid (within 5-6 seconds) flocculation of the casein is separated from whey alcohol, will indicate high quality milk, if the flakes will appear with a considerable delay, you know – milk diluted with water.
By the time of formation of casein flakes to judge the degree of razbavlenii milk water. If the formation of flakes it took about a minute, 20% of the volume of milk is replaced by water, the time interval in 25-30 minutes will indicate the content in the milk of 40% of the water, as if flakes of casein began to appear only after 40 minutes, the milk diluted with water half.
Pouring in a glass of warm water trickle a small amount of milk can with high probability determine whether it was before diluted with water.
High-quality milk in the form of a white clot will gather at the top of the Cup, the diluted milk will behave differently – it is almost completely dissolved in the water, turning it into a dirty-white color.
Another way to determine the degree of razbavlenii milk water. For want of a filter paper you can use paper towel or toilet paper, the main requirement is that they must be of sufficient quality.
Dipped in milk thin stick, toothpick or matchstick, you need to put on the surface of filter paper a small drop of milk. It is very important it to be smaller and with maximum convex shape resembling a hemisphere. For the reliability of the result of these drops is better to put several.
Since the filter paper has a fine-pored structure of the surface, it will start to absorb the water contained in the milk. Thus on the surface of the paper drops will appear around the wet ring, the ring width will be greater, the larger the amount of water in milk.
A drop of undiluted milk will create a damp ring of a thickness not exceeding 1 mm, at room temperature it will dry in about 2 hours. Water ring around drops of milk diluted with water by 10%, will be significantly wider and will dry more quickly – about an hour. For half an hour dry ring around a drop of milk, diluted by 30%, and drying the rings left by a drop of milk divorced in half with water, need only 10-15 minutes.
Unfortunately, at home it is impossible to check whether the purchased product is natural or made from powdered milk. But check milk for the presence of antibiotics and various substances inhibiting the growth of bacteria is very simple. Natural without additives and milk, left at room temperature for a day should turn sour. If not, then chemicals in it – loads.Let the milk purchased by you will always be quality, wholesome and natural!
Drink his health! Bon appétit!