Why does milk turn sour? What gives it sour taste?

Milk is a great thirst quencher and provides the body with the necessary nutrients needed for growth and development. In fact, no mammal can survive without it. Whether it’s a kitten, deer, elephant, a dolphin, or a human being, the first things they will be eating at the onset of their lives is milk.

However, despite its beneficial elements and distinct pleasing taste, one drawback of milk is that it is easy to spoil. But why is it so, and why does it turn sour?

First, let look at what constitutes milk. It is a nutritious, multi-component fluid created by the mammary glands to feed babies. Basically, it is components of different microelements, such as zinc, iron, copper, iodine, fluorine, and chromium. There are also macroelements, like its abundant calcium, and others like fluorine, magnesium, phosphorous, sodium, sulfur, and chlorine. Vitamins, fats, proteins, lactose enzymes are also present in milk. You might be surprised though that it also contains bacteria, such as lactobacilli, pseudomonas, micrococci, etc.

Now, why does milk turn sour? Well, as you see, bacteria are present in milk. In their standard form, they do not cause harm to the organism whose drinking it. However, due to certain outside factors, these bacteria will starts to multiply. Thus, turning the lactose component into lactic acid. Like most acids, lactic acid also possesses a sour taste.

The speed on how the milk will go bad depends on various elements. First is the temperature. The higher it is, the more sour the milk can be. The medium or container also plays a role. If it contains fat, dust, water, and other substances, the faster the milk can turn sour.

Of course, bad milk can surely be disgusting on a bowl of cereal, a cup of coffee, or a banana shake. If ever you accidentally gulp one, it is undoubtedly an odd way to start your day. With that, it is imperative to look for signs that your milk has gone bad.

When the milk begins to sour, it will start to release a rancid, unpleasant odor. It is subtle at first and, from time to time, outwits the power of the human nose, which is people tend to drink them inadvertently. However, as time pass by, the scent becomes more potent and will be harder to miss.

The milk’s taste will inevitably begin to change. The sour or acidic flavor will instantly replace its natural sweetness. Moreover, you can also see changes it is appearance and texture as well. As bad milk will start to develop a chunky, grimy, or slimy, yellow color.

While you shouldn’t try to drink bad milk, it is still far from being to no purpose. If the milk hasn’t curdled yet or grows mold and is just slightly acidic, there is an array of ways to use it in the kitchen.

You can use it as a substitute for buttermilk, sour cream, or yogurt in recipes like pancakes, cornbread, and biscuits. If you love cheese, you can use it to create a farmer’s or cottage cheese. Soups, casseroles, and stews can also benefit from sour milk as few amounts can help thicken it and add a distinct richness, making every sip a palatable one. Lastly, you can use it as a tenderizer, marinate fish or meat, or soak grains and beans to soften them.

More Readings:

Milk (Wikipedia)

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