louis pastuer
Pasteurisation does not kill all bacteria in the milk. Some bacteria are not killed in the heating process and will start to multiply again after pasteurisation. Cooling after pasteurisation is needed in order to limit the amount of bacterial growth that occurs. Bacteria reproduce very slowly in cold conditions, but very quickly in hot conditions. Cooling is the only preservative that is used after pasteurisation.
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PASTEURISATION
There is none
Milk
louis pasteur
None, other than the cost
Yes
pasteurization
he discovered pasteurisation
Pasteurisation kills any microorganisms (e.g. bacteria, fungi) that might be in the milk that could cause it to go sour or spoil.
There are a couple of methods for pasteurisation: 1. Batch pasteurisation In this method milk is heated in a tub while stirring to not less than 63°C for at least 30min. This is followed by cooling within 30min to below 5°C. This method is less commonly used today. 2. High temperature short time pasteurisation Using a continuous system (stainless steel pipelines) milk is pumped through heat exchangers for pasteurisation at 72°C for 15 seconds. After this it is cooled down to below 5°C quickly through heat exchangers. The more the temperature is increased, the less time is needed for the pasteurisation to be effective. After pasteurisation, the standard test to see if it was effective is the phosphatase test.