Food spoilage and poisoning

• Causes of spoilage

  Enzyme Action

  • Ripening of Food: Enzymes naturally present in fruits and vegetables lead to ripening, softening the texture and changing the flavour and colour.
  • Browning of Food (Enzymatic Browning): Occurs when cut or bruised fruits and vegetables are exposed to oxygen.
  • Enzymatic Deterioration: Enzymes break down food components like proteins, fats, and carbohydrates, leading to spoilage.
• Controlling enzymic spoilage

  • Acids: Citric or ascorbic acid can inhibit enzymatic browning.
  • Heat: Cooking or blanching denatures spoilage enzymes.
  • Additives (Preservatives): Chemicals like sulfites prevent enzymatic reactions.
  • Cold Temperatures: Refrigeration slows down enzyme activity.
  • Blanching: Briefly cooking food in boiling water or steam to inactivate enzymes.
• moisture loss

  • Dehydration: Loss of water content leads to dry and tough textures in foods like fruits, vegetables, and meats.
  • Control Measures: Proper packaging and storage conditions help to retain moisture.
• Microbial Contamination

  • Yeasts and Moulds: Fungi that cause spoilage, especially in acidic foods and those with low moisture content.
  • Bacteria: Can cause spoilage in a variety of foods, particularly in protein-rich and high-moisture foods.
• Chemical food poisoning

  • Causes: Contamination of food with harmful chemicals, such as pesticides, cleaning agents, or metals like lead and mercury.
  • Prevention: Proper storage, handling, and use of chemicals, and adherence to safety regulations.
• Biological food poisoning

  • Causes: Caused by eating foods that naturally contain poisonous food substances.
  • Examples: Solanine in green potatoes and amatoxin in poisonous mushrooms.
• Bacterial food poisoning

  • Infectious Food Poisoning: Caused by consuming foods contaminated with bacteria that infect the gut.
  • Examples: Salmonellosis (Salmonella), and Campylobacteriosis (Campylobacter).
• Symptoms of food poisoning

  • Nausea, vomiting, diarrhoea, abdominal pain.
• Toxic food poisoning

  • Caused by consuming toxins produced by bacteria in food.
  • Examples: Botulism (Clostridium botulinum toxin), Staphylococcal food poisoning (Staphylococcus aureus toxins).