Food spoilage, hygiene and storage
Explain the action of enzymes, bacteria, yeasts and moulds and apply personal, food and kitchen hygiene to storage and waste.
Section Paper 1 · Theory · Subject knowledge and written application
Exam scope and assessment notes
This original StudyForA lesson maps Cambridge IGCSE Food & Nutrition 0648 topic 10 for examinations in 2026–2029. These are not Cambridge questions, mark schemes or official grades. The practical examination is a real, centre-administered cooking test with a planning session and assessed preparation, time management, results and quality. These screen-based lessons can teach the theory and help rehearse planning and evaluation, but they cannot provide a kitchen, verify safe food handling or practical skill, replace teacher-supervised cooking, award the practical mark, or guarantee an exam grade. Follow your centre’s instructions, local food-safety rules, medical advice and emergency procedures. Any meal examples are for syllabus practice, not individual dietary or medical advice.
Before you begin
Work on paper. Try each question before revealing help, and explain why your method works.
Quick readiness check
Before you start: What does cross-contamination mean?
What you will learn
- Distinguish biological and enzymic spoilage
- Reduce contamination and cross-contamination
- Explain why refrigeration slows many spoilage processes
- Plan storage and waste handling using product and local guidance
What causes food to spoil
Food can change because of enzymes naturally present in it or microorganisms. Enzymes can cause ripening, softening, colour or flavour changes. Bacteria can multiply and break down food components, causing changes such as souring or decomposition. Yeasts ferment sugars and can produce gas and alcohol; moulds grow as visible networks and release enzymes that alter food. Some microorganisms spoil food and some cause illness. Spoilage signs are not a reliable way to prove food is safe; some hazards cannot be seen or smelled.
Growth depends on factors such as time, temperature, moisture, food type and acidity. Refrigeration slows many microbial and enzyme processes but does not sterilise food or make it safe indefinitely. Follow the product’s use-by, storage and cooking instructions and local food-safety rules.
Hygiene, refrigeration and waste
Personal hygiene includes clean hands, suitable clothing and covering cuts; food hygiene includes clean ingredients and preventing contamination; kitchen hygiene includes clean equipment and work surfaces. Separate raw and ready-to-eat foods, use clean utensils, and manage allergens to reduce cross-contamination. Shops and markets also need clean handling, protected displays and suitable storage.
Store food promptly at the temperature and conditions on its label, keep raw items from contaminating ready-to-eat foods, and use covered containers where suitable. Refrigerate or freeze according to product directions and avoid overloading equipment in ways that prevent proper cooling. Dispose of waste in covered, designated containers and clean spills promptly; local rules determine recycling and food-waste handling.
Sources for this lesson
Pause and explain
What does refrigeration generally do to many spoilage processes?
Worked example
Raw poultry and ready-to-eat salad are prepared on the same unwashed board. Explain the risk and a safer workflow.
Show the worked solution
- Raw food can transfer microorganisms to ready-to-eat food.
- Use separate clean equipment or clean and sanitise it appropriately between tasks.
- Wash hands and store raw food below or apart from ready-to-eat items.
Answer Microorganisms from raw poultry may transfer to salad that will not be cooked. Use separate equipment or clean it thoroughly between tasks, wash hands, and store raw food so it cannot drip onto ready-to-eat food. Follow local food-safety guidance.
Try a topic test
Choose Easy, Normal or Difficult. Save your answers and open worked review after finishing.
Test this topic →From guided practice to a new situation
Write your answer and reasoning first. Use a hint only if you are stuck. The model solution is for self-checking; your written work is not automatically marked.
A container of cooked food is left at room temperature before being stored. Explain why time and temperature matter and what a safe decision should use.
Give me a hint
Microorganisms may grow under suitable conditions; follow the actual product and local rules.
Compare my reasoning
- Explain that time and temperature affect microbial growth.
- Avoid guessing a universal safe time from the case.
- Use local food-safety rules and the food’s cooking and storage instructions.
Many microorganisms can multiply when food remains in suitable conditions for long enough. The safe response depends on the food, conditions and applicable local guidance; use authoritative storage instructions rather than deciding by appearance or smell alone.
Look for these in your work
- Connects growth to time and temperature
- Avoids inventing a threshold
- Uses authoritative instructions
A market stall sells chilled food in an uncovered display beside raw produce. Identify two hygiene checks.
Give me a hint
Look at temperature control, protection, separation and handling.
Compare my reasoning
- Check that chilled food is held under the required temperature conditions.
- Check that food is protected from contamination and kept separate from raw items.
- Review clean utensils, hand hygiene and product dates.
Check that the chilled food remains at the required temperature and is protected from contamination. Keep raw items separate, use clean utensils and hands, and check storage and date controls. The exact temperature standard should come from local food-safety requirements.
Look for these in your work
- Checks temperature control
- Checks separation and protection
- Uses local standards
A family throws away food whenever it passes its best-before date. Explain why a date label should be read with storage and food-safety information.
Give me a hint
Different dates communicate different things; inspect the exact label and local rules.
Compare my reasoning
- Read whether the label is a use-by or best-before date.
- Check storage conditions and whether the package was opened or prepared.
- Follow food-safety guidance; do not rely only on smell or appearance.
Date labels have different meanings, and storage conditions and opening instructions affect how they apply. Read the exact label and follow local food-safety guidance. Appearance and smell alone cannot prove that potentially hazardous food is safe.
Look for these in your work
- Distinguishes label meanings
- Checks storage context
- Does not use sensory inspection as proof of safety
Common mistakes
- Assuming food is safe because it looks or smells normal
- Treating refrigeration as sterilisation
- Using the same tools for raw and ready-to-eat foods without cleaning
What can you explain now?
What does refrigeration generally do to many spoilage processes?
Compare with the explanation
Slows them but does not sterilise the food
Use the syllabus concept, connect it to the stated evidence or needs, and explain any limit on your conclusion.
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Make it stick
Why are clean hands, separated equipment and correct cold storage parts of one hygiene system?
If you needed the solution, close it and solve the problem again from a blank page. A correct answer is stronger when you can explain the reason for each step.