Milk gets spoiled over a period of time due to harmful bacteria. It is preserved by a method known as pasteurisation where milk is boiled for 15 minutes at 72° C and then cooled. This process kills harmful bacteria. However in this change, no new substance is formed amd milk retains its original properties. It is a physical but irreversible change.
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Milk gets spoiled over a period of time due to harmful bacteria. It is preserved by a method known as pasteurisation where milk is boiled for 15 minutes at 72° C and then cooled. This process kills harmful bacteria. However in this change, no new substance is formed amd milk retains its original properties. It is a physical but irreversible change.
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It is a chemical change