Food spoilage and preservation

• What is one advantage of food preservation?


  It avoids food waste.
• What are the methods of home preservation?

  • Freezing
  • Heat treatments
  • Chemical preservation
  • Dehydration
• How does freezing preserve food?


  By using low temperatures to inactivate microorganism growth and slow down enzyme activity.
• What should be done before freezing food?

  Food should be wrapped well to prevent freezer burn.
• What are the guidelines for home freezing?

  • Turn on the fast-freeze button 3–4 hours in advance.
  • Cool food before freezing.
  • Avoid freezing more than one-tenth of the freezer capacity in 24 hours.
  • Freeze foods in usable quantities.
  • Blanch vegetables before freezing.
  • Use strong, airtight, moisture-proof packaging.
  • Label packaging.
• What is the recommended temperature for the fast-freeze compartment?


  • 25°C.
• What is the first step in the jam-making process?


  Weigh out ingredients accurately.
• What is the purpose of adding sugar in jam-making?


  To help preserve the fruit and enhance flavor.
• What is the importance of sealing jam after making it?

  To prevent the re-entry of microorganisms.
• What are the steps in the chutney-making process?


  • Boil fruit and vegetables at 100°C.
  • Add sugar and vinegar.
  • Seal the chutney to prevent re-entry of microorganisms.
• What is the underlying principle of chemical preservation?


  It creates a concentrated solution that dehydrates microbial cells and lowers pH to inhibit growth.
• What are suitable foods for home dehydration?

  • Herbs (e.g., basil, rosemary)
  • Vegetables (e.g., chillies, parsnip crisps)
  • Fruits (e.g., apple slices, banana chips)
• What is the principle behind fermentation?


  It is the breakdown of carbohydrates by microorganisms to produce carbon dioxide, alcohol, and energy.
• What does irradiation do to food?


  It destroys microorganisms and prevents sprouting on vegetables.
• What are the advantages and disadvantages of irradiation?


  Advantages:

  • Destroys microorganisms
  • Kills pests
  • Slows ripening

  
  

  Disadvantages:

  • Strict legislation governs its use
  • May affect food quality
• What is the purpose of blanching vegetables before freezing?


  To preserve color and texture.
• What is the recommended storage time for frozen foods?


  Foods should only be stored for their recommended storage time.
• What is the first-in-first-out (FIFO) system in food storage?


  It is a method of using older foods before newer ones.
• What should be done when thawing food?


  Thaw food in the fridge and never refreeze thawed food unless cooked first.
• What is the importance of sterilizing jars before making jam?


  To remove microbes that could spoil the jam.
• What is the purpose of using a wooden spoon in chutney-making?

  To avoid reactions with the acid in vinegar.
• Why should cellophane covers not be used for chutney?


  They allow evaporation to take place inside the jar.
• What is the role of pectin in jam-making?


  Pectin helps the jam to set.
• What is the effect of adding vinegar in chutney-making?


  It helps to preserve the chutney by lowering the pH.
• What is the purpose of using brown sugar in chutney-making?


  It gives a richer color to the chutney.
• How does dehydration preserve food?


  By removing moisture, inhibiting microbial growth, and inactivating enzymes.
• What is the underlying principle of canning and bottling?


  Using high temperatures to destroy microorganisms and sealing food in airtight containers.
• What is the purpose of removing air from cans during the canning process?

  To prevent the growth of microorganisms.
• What is the role of labeling in the canning process?


  To provide information about the contents and date of canning.
• What is the effect of sulfur dioxide in dried fruits?


  It acts as a chemical preservative.
• What is the purpose of using antioxidants in food preservation?


  To prevent oxidation and spoilage of food.
• What is the role of lactic acid bacteria in fermentation?


  They convert lactose into lactic acid.
• What is the significance of the Radura symbol on irradiated foods?


  It indicates that the food has been treated with ionizing radiation.
• What are the effects of preservation on food?


  It maintains color, taste, texture, flavor, and nutritional value.