Introduction: Milk is a great thing. Some people drink it every day, while others always keep it at home. However, if the milk you buy is not fresh or pure enough, its nutritional value is greatly diminished, and it can even harm your health. So, how can you tell if milk is fresh and not spoiled? The following will teach you a few methods to tell.
Method 1: Sensory Identification. Fresh milk (pasteurized milk) is milky white or slightly off-white, with the natural fresh aroma of cow's milk, no off-flavors, a uniform fluid with no sediment, no curdling, no impurities, no foreign objects, and no viscous phenomenon.
Method 2: Drop a bit of milk into clear water. If it does not disperse, it is fresh milk. If it disperses, it is not fresh milk. For bottled milk, if a thin layer is observed at the top or there is sediment at the bottom, it is not fresh milk.
Method 3: Boiling Test. Take about 10ml of milk sample in a test tube (or a transparent glass), place it in boiling water for 5 minutes and observe. If curdling or flocculent matter is produced, it indicates that the milk is not fresh or has spoiled.
Method 4: Good milk doesn't leave a residue. Quickly pour the purchased milk (not boiled or microwaved) into a clean, transparent glass, then slowly tilt the glass. If a thin milk film is left on the inner wall of the glass, does not stick, and can be easily washed off with water, then it is made from fresh raw materials. This type of milk is delivered to the processing plant in a short time and has a very low total bacterial count. If the milk film on the glass is uneven, or if there are even tiny, visible particles sticking to the wall that are difficult to clean, it means the milk is not fresh enough.
Besides these "original" little tricks, there are also some recognized principles that can help you choose high-quality milk. First, among products of the same price, choose the one with a higher fat content. Generally, the higher the milk fat content of raw milk, the better the quality. Unlike protein, milk fat rarely has artificial chemical adulteration. A high protein content does not necessarily mean the milk is of high quality. Second, among products with the same fat content, choose the one that has been pasteurized, as pasteurized products retain nutrients more comprehensively.
In addition, it is also necessary to distinguish between pure milk and milk-containing beverages: Pure milk is also called fresh milk or pure fresh milk. From the product's ingredient list, you can see that it has only one ingredient: fresh milk. The quality of pure milk is mainly judged by two indicators: total solids (also called total milk solids) and protein. The content of these two indicators is usually stated on the product packaging. The higher their content, the higher the nutritional value of the milk, and generally, the price will be relatively higher. Furthermore, yogurt, which is very popular among consumers, is made by fermenting pure milk, so yogurt also belongs to the category of pure milk.