Section Revision: Food Safety

This lesson provides a comprehensive revision of food safety content for the AQA GCSE Food Preparation and Nutrition exam (8585), covering bacteria, temperatures, storage, cross-contamination and hygiene.

---

Key Temperatures

These are the most frequently tested facts in the food safety section:

Temperature	Significance
-18°C	Freezer — bacteria dormant (NOT killed)
0–5°C	Fridge — bacterial growth very slow
5–63°C	DANGER ZONE — bacteria multiply rapidly
37°C	Optimum for most pathogenic bacteria (body temperature)
63°C	Hot holding minimum (top of danger zone)
72°C	Pasteurisation (72°C for 15 seconds)
75°C	Core cooking and reheating minimum
100°C	Boiling point
135°C	UHT treatment (135°C for 1–4 seconds)

Exam Tip: These temperatures appear in almost every food safety exam. Learn them so thoroughly that you can recall them instantly.

---

The Five Food Poisoning Bacteria

Bacterium	Main Source	Onset	Key Symptom	Serious Complication	Unique Feature
Campylobacter	Raw poultry	2–5 days	Bloody diarrhoea	Guillain-Barré syndrome	Most common in UK; do NOT wash chicken
Salmonella	Poultry, eggs	12–72 hrs	Diarrhoea, vomiting	Septicaemia	Lion mark eggs; egg vaccination
E. coli O157	Raw beef (mince)	1–4 days	Bloody diarrhoea	HUS (kidney failure)	Very low infective dose (~10 bacteria)
Listeria	Soft cheese, pâté	1–70 days	Flu-like; meningitis	Miscarriage/stillbirth	Grows at fridge temperatures
S. aureus	Human skin, nose, cuts	1–6 hrs	Violent vomiting	Dehydration	Heat-resistant toxins

Quick Onset Order (fastest to slowest)

flowchart LR
    A["S. aureus<br/>1-6 hrs"] --> B["Salmonella<br/>12-72 hrs"]
    B --> C["E. coli O157<br/>1-4 days"]
    C --> D["Campylobacter<br/>2-5 days"]
    D --> E["Listeria<br/>1-70 days"]

    style A fill:#e74c3c,color:#fff
    style E fill:#2c3e50,color:#fff

---

Cross-Contamination Prevention

Method	How It Prevents Cross-Contamination
Raw meat on bottom shelf	Prevents drips falling on ready-to-eat food
Separate chopping boards	Red = raw meat; Blue = raw fish; Green = salad; Yellow = cooked meat
Separate utensils	Different knives and tongs for raw and cooked food
Handwashing	Removes bacteria between handling different foods
Clean and disinfect surfaces	Two-stage process: clean (remove dirt) then disinfect (kill bacteria)
Do not wash raw chicken	Washing splashes bacteria around the kitchen
Cover foods	Prevents bacteria from one food reaching another

---

Personal Hygiene

Requirement	Detail
Handwashing	Hot soapy water; at least 20 seconds; between fingers, under nails, wrists
When to wash	Before food prep; after raw meat; after toilet; after touching face/hair; after pets
Hair	Tied back; hair net in commercial kitchens
Clothing	Clean apron; remove outdoor clothing
Nails	Short, clean; no nail polish or false nails
Jewellery	Remove rings, watches, bracelets
Cuts	Blue waterproof plaster (visible; contains metal strip for detection)
Illness	48-hour rule: symptom-free for 48 hours before returning to food handling
Temperature probes	Insert into thickest part; avoid bone; clean before and after use

---

Storage Principles