Factors involved in spoilage of MILK
Milk is every household’s staple. Whether it is fresh, it is sold in packets/pouches, or in a carton processed to extend its shelf life for months. Milk has many nutrients: protein and lactose.
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Yet, compared to other staples, milk does not have a long shelf life, lasting only for two to four days. In the case of milk cartons, they have a shelf life up to 6 months, but once opened, they must be consumed in a day or two.
Harmful germs are present in raw milk, such as bacteria, viruses, and parasites, that can make you very sick. Do not consume milk, which is not pasteurized (heated to a specific temperature for a set amount of time). The harmful germs don’t change the look, taste, or smell of raw milk. Pasteurization is the only way to ensure the milk is safe for consumption.
Hence, most of the milk we buy from the store is already pasteurized under high temperatures.
Here are a few tips on how to handle milk right from the store to consumption.
At the store.
Read your label properly. For example, Mfg dated:-10.06.2020 Time:- 00:00:00, Use by date:- 13.6.2020 Time:- 00:00:00. So that at least you have some time to store the product and use them fully.. Kindly note, milk will not be consumable beyond 13.6.2020. Don’t buy milk or other dairy foods if you can’t use them before the “use by” date.
Isolate the milk packet away from other products for some time. Wash the packet with warm running water and store the milk in the chiller-milk trays.
Before consuming, boil the milk (100*C) and consume it within a day. Ensure the vessels used are clean so that this must not cause hazards during the process.
Refrigerate milk and milk products between 0–5*C. Never store milk in the refrigerator door where it is susceptible to warmer temperatures caused by the opening and closing of the door.
Keep milk containers closed to prevent the absorption of other flavors. Although this could change the taste, the milk itself is still safe.
Never store milk, butter, cheese in the freezer. Storage conditions are different with ice creams and frozen yogurt.
When opening milk pouches, there should be no odor whatsoever. Spoiled milk smells sour and even foul. The color will most likely stay white, but a tainted or sour smell is the key indicator that the milk should not be consumed.
Factors playing a major role in spoilage of milk
Light plays a major role in the spoilage of milk. It is advisable to store under artificial light or sunlight.
Milk absorbs flavors of other ingredients. Keep the container closed. A strong pungent smell from garlic and onion can be one of the major factors affecting the quality of the milk.
Milk when left outside for a long period of time, spoils. If milk is not consumed within its validity period it will not be good for consumption.
Milk if not stored between 0–5 C, will get spoiled. If the temperature shifts too much, milk spoils more. Do not reheat already boiled milk. Continual and rapid temperature shifts can breed bacteria such as lactococci and lactobacilli.
Microorganisms involved in spoilage are psychrotrophic ( bacterias that grow at low temperature) organisms. Some strains of Bacillus, Clostridium, Lactobacillus, Micrococcus, and Streptococcus survive pasteurization and grow at refrigeration temperatures which can cause spoilage problems.
Adulteration is a method of making food unsafe for consumption by adding extraneous ingredients. In milk, they usually add starch or water to increase the volume.
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Ways to identify adulterants in milk:-
On a white porcelain plate, add two to three drops of milk and slide them away. Under the light, if you notice any traces of water, then the milk is adulterated with water.
Another method of adulteration is the addition of starch content. Add a few drops of iodine tincture to the milk, if the milk turns blue, then it is adulterated with starch content.