Buying and Storing Food

This lesson covers the principles of buying and storing food safely, including critical temperatures, date marks, and correct fridge positioning, as required by the AQA GCSE Food Preparation and Nutrition specification (8585), section 3.4. Proper food storage is one of the most practical and frequently examined aspects of food safety.

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Critical Temperatures Recap

Temperature control is the foundation of safe food storage. You must know these critical temperatures:

Temperature	Significance	Key Rule
-18°C	Freezer temperature	Bacteria are dormant; food can be stored for months
0–5°C	Fridge temperature	Bacterial growth is very slow; store perishable foods here
5–63°C	Danger zone	Bacteria multiply rapidly — minimise time in this range
63°C	Hot holding minimum	Bacteria cannot multiply above this temperature
75°C	Core cooking/reheating temperature	Most bacteria are killed at this temperature
100°C	Boiling point	Used for sterilisation and pasteurisation

graph TB
    A["🔴 100°C Boiling"] --- B["🟠 75°C Cooking / Reheating<br/>Bacteria killed"]
    B --- C["🟡 63°C Hot Holding<br/>Top of danger zone"]
    C --- D["🔴 37°C Body Temperature<br/>Optimum for bacteria"]
    D --- E["🟡 5°C Fridge Top Limit<br/>Bottom of danger zone"]
    E --- F["🔵 0-5°C Fridge Range<br/>Slow bacterial growth"]
    F --- G["🔵 0°C Freezing Point"]
    G --- H["⚪ -18°C Freezer<br/>Bacteria dormant"]

    style C fill:#ff6b6b,color:#fff
    style D fill:#ff6b6b,color:#fff
    style E fill:#ff6b6b,color:#fff
    style F fill:#4ecdc4,color:#fff
    style H fill:#45b7d1,color:#fff

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Date Marks: Use By vs Best Before

Understanding the difference between use-by dates and best-before dates is essential for food safety and is a common exam topic.

Use-By Date

The use-by date is about food safety:

• Found on perishable, high-risk foods (fresh meat, fish, dairy, ready meals, prepared salads)
• It is illegal for shops to sell food after its use-by date
• Food should not be eaten after the use-by date, even if it looks and smells fine
• After this date, pathogenic bacteria may have multiplied to dangerous levels
• The use-by date is only valid if the food has been stored according to the storage instructions on the label (e.g., "Keep refrigerated below 5°C")

Exam Tip: The key point about use-by dates is safety. Eating food past its use-by date is a food safety risk, even if the food appears normal. This links to the fact that pathogenic bacteria do not change the appearance, taste or smell of food.

Best-Before Date

The best-before date is about food quality:

• Found on longer-life foods (canned goods, dried pasta, biscuits, cereals, frozen foods)
• Food is safe to eat after the best-before date, but it may not be at its best quality
• Texture, flavour or nutritional content may have deteriorated
• It is not illegal to sell food past its best-before date (except for eggs, which have a legal best-before date of 28 days)
• Use common sense — check appearance, smell and texture

Comparison Table

Feature	Use-By Date	Best-Before Date
About	Safety	Quality
Found on	Perishable, high-risk foods	Longer-life, shelf-stable foods
After the date	Do NOT eat — risk of food poisoning	Safe to eat, but quality may decline
Legal to sell after?	No — it is illegal	Yes (except eggs)
Examples	Fresh meat, milk, cream, sandwiches	Canned food, pasta, biscuits, cereals

Display-Until and Sell-By Dates

• Display until and sell by dates are for shop staff, not consumers
• They help with stock management and rotation
• They are not required by law and are being phased out to reduce food waste
• Consumers should use the use-by or best-before dates for guidance

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Correct Fridge Storage and Positioning

A fridge should be set between 0°C and 5°C. The positioning of food within the fridge is important to prevent cross-contamination and ensure food stays safe.

Fridge Layout

graph TB
    subgraph "Correct Fridge Layout"
        A["TOP SHELF<br/>Ready-to-eat foods<br/>Cooked meats, leftovers,<br/>dairy products"]
        B["MIDDLE SHELF<br/>Dairy, eggs, deli items<br/>Butter, cream, yoghurt"]
        C["BOTTOM SHELF<br/>Raw meat, poultry, fish<br/>In sealed containers<br/>to prevent drips"]
        D["SALAD DRAWER<br/>Fruit, vegetables, salad<br/>Washed and prepared"]
        E["DOOR<br/>Condiments, juices,<br/>jams, dressings<br/>(least cold area)"]
    end

    A --- B
    B --- C
    C --- D

    style A fill:#27ae60,color:#fff
    style B fill:#2980b9,color:#fff
    style C fill:#e74c3c,color:#fff
    style D fill:#f39c12,color:#fff
    style E fill:#9b59b6,color:#fff

Key Principles of Fridge Storage

Principle	Explanation
Raw meat on the bottom shelf	Prevents raw juices dripping onto ready-to-eat foods below — this is the single most important rule
Ready-to-eat foods on top shelves	Keeps them away from potential contamination by raw foods
Cover all foods	Use lids, cling film or sealed containers to prevent cross-contamination and moisture loss
Do not overload the fridge	Air must circulate freely to maintain the correct temperature throughout
Allow hot food to cool first	Placing hot food in the fridge raises the internal temperature, putting other foods at risk
Keep the fridge clean	Wipe up spills immediately; clean regularly to prevent bacterial build-up
Check temperature regularly	Use a fridge thermometer; the built-in dial is not always accurate
Door is the warmest area	Store condiments and drinks here, not high-risk foods
Keep the door closed	Frequent opening raises the temperature

Exam Tip: If asked about fridge storage, always state that raw meat must go on the bottom shelf and explain why — to prevent raw juices dripping onto ready-to-eat foods. This demonstrates understanding rather than just recall.

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Freezer Storage

The freezer should be at -18°C or below. Key principles:

Principle	Explanation
Label and date food	So you know what it is and how long it has been frozen
Follow star ratings	⭐ (-6°C, 1 week), ⭐⭐ (-12°C, 1 month), ⭐⭐⭐ (-18°C, 3 months), ⭐⭐⭐⭐ (-18°C, 3–12 months depending on food)
Freeze food quickly	Rapid freezing produces smaller ice crystals, causing less damage to food cell structure
Do not refreeze thawed food	Once thawed, bacteria resume growth; refreezing allows bacterial numbers to accumulate through multiple thaw cycles
Defrost the freezer regularly	Ice build-up reduces efficiency and raises temperature
Use freezer bags or containers	Prevent freezer burn (dehydration of the food surface)

Thawing Food Safely

Method	Detail
In the fridge	Safest method — food stays cold while thawing. Allow plenty of time (large items may take 24–48 hours). Place on the bottom shelf in a container to catch drips.
In the microwave	Use the defrost setting. Cook food immediately after microwave defrosting, as some areas may have started to cook and entered the danger zone.
Never at room temperature	The outer surface thaws first and enters the danger zone while the centre remains frozen.
Cook from frozen	Some foods (e.g., frozen vegetables, thin items) can be cooked directly from frozen. Check packaging instructions.

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Buying Food Safely

Good food safety begins at the point of purchase:

In the Shop

Principle	Explanation
Check date marks	Choose items with the longest remaining date; check use-by dates are not expired
Inspect packaging	Reject dented cans, torn packaging, swollen packs, or broken seals
Check temperature	Chilled foods should feel cold; frozen foods should be solid
Pick up chilled/frozen items last	Minimise time out of cold storage
Use insulated bags	Cool bags or insulated bags for transporting chilled and frozen items, especially in warm weather
Separate raw and ready-to-eat	Keep raw meat separate from other foods in the trolley and shopping bags

At Home

Principle	Explanation
Unpack quickly	Put perishable items in the fridge or freezer as soon as possible — within 30 minutes of purchase
Check your fridge temperature	Ensure it is between 0°C and 5°C
First in, first out (FIFO)	Place new items behind older items so older food is used first
Follow storage instructions	Check labels for specific storage requirements (e.g., "Once opened, consume within 3 days")
Store in appropriate containers	Transfer opened food to clean, sealed containers

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Stock Rotation: First In, First Out (FIFO)

The FIFO (First In, First Out) principle ensures food is used in the correct order: