Preservation Flashcards
What is food preservation?
Is a treatment to the food to delay spoilage and inhibit the growth of pathogenic organisms which would otherwise make the food unfit to consume.
What are the treatments involved in preservation?
Use of low or high temperatures Take away the moisture Use of chemicals Controlled atmospheres and restriction of 02 in vacuum packaging Smoking Irradiation
How does the low temperature preservation method work?
Bacterial growth will be slowed in temperatures under 5 degrees however mould can still cause spoilage at these temperatures
How does the high temperature preservation method work?
Hate is used to destroy enzymes and bacteria however some bacteria is heat resistant.
How does the freezing preservation method work?
The moisture is frozen so the bacteria becomes dormant however some may die. Moulds and yeasts can still survive but it is unlikely for them to survive under -10 degrees.
What is blanching?
Blanching is when vegetables are placed in hot water for 1 minute and then frozen quickly to be preserved. The boiling water destroys any enzymes and bacteria.
How does the pasteurisation preservation method work?
The milk is heated to 72 degrees for 15 seconds then cooled rapidly to below 10 degrees. This destroys any pathogenic bacteria.
What is pasteurisation used for?
Milk which is kept in the fridge.
What does UHT stand for?
Ultra heat treatment.
What is UHT used for?
To maintain taste, texture and nutritional value.
How does the UHT preservation method work?
Heated to a minimum of 135 degrees for 1 second before being stored into sterile containers. This can be kept for several months.
How does the sterilisation preservation method work?
Temperatures are heated to 100 degrees then sealed into either a tin or can.
What does sterilisation destroy?
All pathogenic bacteria.
How does the spoking preservation method work?
Foods are preserved by removing the moisture.
How does the irradiation preservation method work?
The bacteria in the food is killed through radiation. Beams of electrons or gamma rays are used which reduces the risk of spoilage, chemicals and insects.
