Why Milk is Spoiled? (The Actual Reasons )

Milk
Milk is a white opaque liquid food made from the mammary glands of mammals. It is the main source of nutrition for infants because they can’t digest solid food in the early stage of their childhood.

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Spoilage of Milk
Milk is an excellent source for the growth of many spoilage microorganisms because it has a high amount of free water, rich in nutrients and ideal pH level for the growth of microorganisms.

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Source of Milk Contamination
Microorganisms are the major cause of spoilage of milk and milk products. These organisms may come from the environment or the people involved in the milking process.

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Types of Milk Spoilage
The undesirable growth of harmful microorganisms may lead the milk to spoilage. These organisms grow in the milk and responsible for many undesirable changes in the physical and chemical properties of milk.

Some common types of milk spoilage are as following;
1. Gas Formation
it's due to the conversion of milk sugar (Lactose) into Lactic Acid, Butyric acid and Co2 gas. This milk is not suitable for human consumption as it may cause adverse effects on human health.

2. Proteolysis
The 2nd type of spoilage is the denaturation of milk proteins (Casein). This is due to the growth of harmful microorganisms and decreasing the pH of the milk. Consumption of such milk causes digestive problems.

3. Sliminess
Sliminess on the milk surface can be observed if the milk is collected from an unhealthy animal who is suffering from MASTITIS (Disease of Udders).

4. Breakdown of Milk Fat
The breakdown of milk fat may cause the production of a bad smell in the milk. During this reaction, the milk fat is attacked by Oxygen and some Enzymes which are responsible for the production of a bad smell in the milk.

5. Change the Milk Colour
Milk has its unique white colour. It differs from animal to animal, like cow milk has a slightly off-white colour while buffalo milk has shiny white colour. The growth of undesirable bacteria also causes a change in milk colour from its natural. Milk with abnormal colour is considered spoiled.