Food preservation Flashcards
Q: What is processed food?
A: Food that has been altered in some way during preparation such as freezing canning, baking, or drying.
Q: Why is food processed?
A: To make food edible,
improve shelf life,
ensure safety,
add variety,
enhance quality,
and offer convenience.
Q: What is food preservation?
A: Treating food to stop or slow spoilage and prevent foodborne illness while maintaining its nutritional value texture, and flavor.
Q: Define “shelf life” of a food product.
A: The time a product remains safe and acceptable under specified storage and packaging conditions.
Q: Difference between ‘use by’ and ‘best before’ dates?
A: ‘Use by’ is for safety; food should not be consumed after. ‘Best before’ is about quality; food is usually still safe but may not be optimal.
Q: What is blanching?
A: Mild heating (<100°C) to preserve color texture, inactivate enzymes, and reduce microbes before freezing or canning.
Q: What is pasteurization?
A: Heating food (like milk or juice) to kill most microorganisms e.g. milk at 72°C for 15 seconds (HTST method).
Q: What is sterilization in food processing?
A: Destruction of all life forms (microbes spores) using high temperatures (>100°C) e.g., autoclaving at 121°C for 15 min.
Q: What is Ultra-High Temperature (UHT) treatment?
A: Sterilizing food at ≥135°C for a few seconds with aseptic packaging to preserve taste texture
Q: What is canning and its relation to pH?
A: Sealing food in containers and applying heat. High pH foods (e.g. meats) need more intense sterilization than low pH foods (e.g.fruits).
Q: What are psychrotrophs?
A: Microorganisms that can grow at refrigeration temperatures causing spoilage.
Q: What is lyophilisation (freeze-drying)?
A: Removing water from frozen food to preserve it by slowing spoilage and microbial growth.
Q: Name non-thermal food preservation methods.
A: Filtration, ultrasonication, cold plasma, pulsed electric fields (PEF), high hydrostatic pressure (HHP), ozone, irradiation.
Q: What is food irradiation?
A: Exposing food to ionizing radiation to kill microorganisms and extend shelf life without significant heating
Q: What are examples of natural food preservatives?
A: Salt, sugar, vinegar, lemon juice, rosemary extract, garlic, and cinnamon.
Q: What is High Hydrostatic Pressure (HHP)?
A: Applying 100–600 MPa pressure to inactivate microbes without heat, preserving taste and nutrients.
