Food safety

🍽 1. Microorganisms and Food Safety

Bacteria

• Single-celled microorganisms that can cause foodborne illnesses.

• Multiply rapidly under favorable conditions: warmth (5–63°C), moisture, food, and time.

• Common food poisoning bacteria:

  • Salmonella: Raw poultry, eggs, unpasteurized milk; causes diarrhea, fever, and cramps.

  • E. coli (Escherichia coli): Raw/undercooked meat, unpasteurized milk, contaminated water; can cause kidney failure.

  • Listeria monocytogenes: Soft cheeses, pâté, unpasteurized milk; grows at refrigeration temperatures; risk for pregnant women and elderly.

  • Campylobacter: Raw poultry, unpasteurized milk; leading UK cause of food poisoning.

  • Staphylococcus aureus: Human skin/nose; produces heat-resistant toxins in warm foods.

  • Clostridium perfringens: Soil, raw meat; spores survive cooking.

  • Clostridium botulinum: Soil, water; dangerous neurotoxin in improperly canned foods.

  • Bacillus cereus: Soil, grains (rice, pasta); spores survive cooking.

  • Shigella: Contaminated food/water; causes dysentery.

  • Contaminant: Campylobacter

    • Onset of symptoms: 2 to 5 days

    • Foods affected and means of transmission: Meat and poultry. Contamination occurs during processing if animal feces contact meat surfaces. Other sources include unpasteurized milk and contaminated water.

    Contaminant: Clostridium botulinum

    • Onset of symptoms: 12 to 72 hours

    • Foods affected and means of transmission: Home-canned foods with low acidity, improperly canned commercial foods, smoked or salted fish, potatoes baked in aluminum foil, and other foods kept at warm temperatures for too long.

    Contaminant: Clostridium perfringens

    • Onset of symptoms: 8 to 16 hours

    • Foods affected and means of transmission: Meats, stews and gravies. Commonly spread when serving dishes don't keep food hot enough or food is chilled too slowly.

    Contaminant: Escherichia coli (E. coli) O157:H7

    • Onset of symptoms: 1 to 8 days

    • Foods affected and means of transmission: Beef contaminated with feces during slaughter. Spread mainly by undercooked ground beef. Other sources include unpasteurized milk and apple cider, alfalfa sprouts, and contaminated water.

    Contaminant: Giardia lamblia

    • Onset of symptoms: 1 to 2 weeks

    • Foods affected and means of transmission: Raw, ready-to-eat produce and contaminated water. Can be spread by an infected food handler.

    Contaminant: Hepatitis A

    • Onset of symptoms: 28 days

    • Foods affected and means of transmission: Raw, ready-to-eat produce and shellfish from contaminated water. Can be spread by an infected food handler.

    Contaminant: Listeria

    • Onset of symptoms: 9 to 48 hours

    • Foods affected and means of transmission: Hot dogs, luncheon meats, unpasteurized milk and cheeses, and unwashed raw produce. Can be spread through contaminated soil and water.

    Contaminant: Noroviruses

    • Onset of symptoms: 12 to 48 hours

    • Foods affected and means of transmission: Raw, ready-to-eat produce and shellfish from contaminated water. Can be spread by an infected food handler.

    Contaminant: Rotavirus

    • Onset of symptoms: 1 to 3 days

    • Foods affected and means of transmission: Raw, ready-to-eat produce. Can be spread by an infected food handler.

    Contaminant: Salmonella

    • Onset of symptoms: 1 to 3 days

    • Foods affected and means of transmission: Raw or contaminated meat, poultry, milk, or egg yolks. Survives inadequate cooking. Can be spread by knives, cutting surfaces or an infected food handler.

    Contaminant: Shigella

    • Onset of symptoms: 24 to 48 hours

    • Foods affected and means of transmission: Seafood and raw, ready-to-eat produce. Can be spread by an infected food handler.

    Contaminant: Staphylococcus aureus

    • Onset of symptoms: 1 to 6 hours

    • Foods affected and means of transmission: Meats and prepared salads, cream sauces, and cream-filled pastries. Can be spread by hand contact, coughing and sneezing.

    Contaminant: Vibrio vulnificus

    • Onset of symptoms: 1 to 7 days

    • Foods affected and means of transmission: Raw oysters and raw or undercooked mussels, clams, and whole scallops. Can be spread through contaminated seawater.

Moulds

• Fungi that grow on food, causing spoilage.

• Some produce mycotoxins, which can be harmful if ingested.

• Appear as fuzzy or discolored patches.

Yeasts

• Single-celled fungi that ferment sugars, producing gas and alcohol.

• Cause spoilage in sugary foods and drinks.

• Beneficial in bread-making and brewing.

Viruses

• Smaller than bacteria; cannot multiply in food but can be transmitted via contaminated food/water.

• Common examples: Norovirus, Hepatitis A.

• Spread via poor hygiene, infected food handlers.

Food Spoilage

• Deterioration of food quality, making it unsafe or unappealing.

• Caused by microorganisms, enzymes, or chemical changes.

• Signs: off-odors, texture changes, color changes, mold growth.

Contamination

• Introduction of harmful microorganisms or substances into food.

  • Biological: bacteria, viruses, parasites.

  • Chemical: cleaning agents, pesticides.

  • Physical: hair, glass, metal.

• Cross-contamination: transfer of harmful bacteria between foods, surfaces, equipment, or handlers.

Food Poisoning

• Illness from consuming contaminated food.

• Symptoms: nausea, vomiting, diarrhea, cramps, fever.

• High-risk groups: young children, elderly, pregnant women, immunocompromised.

Implications of Food Poisoning

• For consumers: health risks, hospitalisation, long-term effects.

• For businesses: legal penalties, fines, closure, reputational damage, financial losses.

🍽 2. Food Safety: Allergenics and Food-Related Illnesses

Food Allergies

• Immune system reaction to specific food proteins.

• Common allergens: peanuts, tree nuts, milk, eggs, fish, shellfish, soy, wheat, sesame, celery, mustard, lupin, molluscs, sulphites.

• Symptoms: hives, swelling, breathing difficulty, anaphylaxis.

Food Allergens

• Substances in food that cause allergic reactions.

• UK law requires clear labelling of the 14 major allergens.

• Businesses must prevent cross-contact in preparation and service.

Food Intolerance/Sensitivity

• Non-immune response to certain foods, usually due to enzyme deficiency.

• Example: lactose intolerance.

• Symptoms: bloating, abdominal pain, diarrhea.

Coeliac Disease

• Autoimmune disorder triggered by gluten (wheat, barley, rye).

• Damages small intestine lining, causing nutrient absorption issues.

• Management: strict gluten-free diet.

Implications for Consumers and Businesses

• Consumers: need accurate allergen information to stay safe.

• Businesses: legal duty to label allergens clearly and train staff; failure can cause serious harm and legal consequences.

🍽 3. Food Safety in Practice

Legislation

• Food Safety Act 1990: ensures food is safe to eat and accurately described.

• General Food Law Regulation (EC) 178/2002: overall food law principles, now in UK law post-Brexit.

• Food Hygiene Regulations 2006 & 2013: outline hygiene requirements, staff training, premises standards.

• Food Information Regulations 2014: require clear allergen labelling and nutritional information.

Systems of Compliance: HACCP

• Hazard Analysis and Critical Control Points (HACCP): identifies, assesses, and controls food hazards.

  • Conduct hazard analysis.

  • Identify critical control points (CCPs).

  • Establish critical limits.

  • Monitor CCPs.

  • Establish corrective actions.

  • Verify system effectiveness.

  • Record-keeping and documentation.

Food Premises

• Clean, well-maintained, designed to prevent cross-contamination.

• Adequate lighting, ventilation, handwashing, and pest control.

• Separate areas for raw and cooked food.

Responsibilities of Food Handlers

• Maintain personal hygiene: wash hands, wear clean clothes, hairnets/hats, no jewelry.

• Report illness to supervisors.

• Follow proper handling to prevent cross-contamination.

• Undergo regular food safety training.

Important Temperatures in Catering

• Fridge: 0–5°C.

• Freezer: -18°C or below.

• Hot holding: above 63°C.

• Cooking: core temp 75°C for 2 minutes.

• Danger zone: 5–63°C where bacteria multiply rapidly.

Protective Clothing

• Aprons, hairnets, hats, gloves — worn to prevent contamination.

• Changed when dirty or after handling raw foods.

Training

• Food handlers must be trained in hygiene and food safety relevant to their tasks.

• Levels 1–3 depending on role; includes refresher courses and updates on legislation.