Community medicine

• Food


  A nutritious substance eaten by human beings or animals to maintain vital life processes
• Food


  • It is a fundamental need, a basic right
  • Essential for the existence of all living things
  • Energy production, survival, prerequisite to good health
  • Social interactions, celebrations, funerals, weddings
  • Satisfying emotional needs, sign of friendship
• Food hygiene


  All sanitary measures, principles, and procedures put in place to ensure that food is free from agents of contamination or disease germs in any form
• Food hygiene


  1. Chain of events from growing in the farm through storage and distribution to finally eating the food

  2. Includes the collection and disposal of food wastes

  3. Possibility of contamination by microorganisms or unwanted chemicals at every step of the chain, directly or indirectly, knowingly or unknowingly
• Food safety


  Food is free from all possible contaminants and hazards
• Objectives of food hygiene

  • Prevent food spoilage
  • Inform and educate people about simple and practical methods of keeping food safe
  • Protect food from adulteration
  • Ensure proper practice in the food trade to prevent the sale of offensive or defective food
• Key considerations in food safety

  • Keep a clean food preparation and serving utensils and environment
  • Separate raw and cooked food
  • Cook food thoroughly
  • Keep food at safe temperatures
  • Hand washing at all times
  • Use safe water and raw materials
• Types of foodstuff


  • Organic: CHO, Proteins, Fats (Energy, growth, tissue repair, cell multiplication)
  • Inorganic: Water, mineral elements, and vitamins (Physiological functions, blood circulation)
• Contamination is the unintended presence of harmful substances or microorganisms in food
• Types of harmful substances to food

  • Biological Hazards: Bacteria, viruses, parasites, fungi
  • Chemical Hazards: Pesticides, food additives, misapplication of food-keeping chemicals
  • Physical Hazards: Foreign matter such as dirt, broken glass, and other objects that accidentally get into food
• Cross-contamination is the transfer of harmful substances or microorganisms to food
• Ways of cross-contamination


  • Hands
  • Food-contact surfaces
  • Cleaning clothes and sponges
  • Raw or contaminated food in contact with cooked food
• Foodborne illnesses are usually infectious or toxic in nature and caused by bacteria, viruses, parasites, or chemical substances entering the body through contaminated food
• Food safety, nutrition, and food security are inextricably linked
• Contaminated food in contact with cooked food

  Risk of foodborne illnesses
• Foodborne illnesses


  Usually infectious or toxic in nature caused by bacteria, viruses, parasites, or chemical substances entering the body through contaminated food
• Global Burden of foodborne diseases

  • An estimated 600 million people fall ill after eating contaminated food
  • 420,000 die every year due to foodborne illnesses
  • 33 million healthy life years (DALYs) are lost annually
  • US$ 110 billion is lost each year in productivity and medical expenses from unsafe food in low- and middle-income countries
  • Children under 5 years carry 40% of the foodborne disease burden with 125,000 deaths annually
  • Foodborne diseases impede socioeconomic development by straining health care systems and harming national economies, tourism, and trade
• Reasons for foodborne disease outbreaks include failure to thoroughly heat or cook food, infected employees, poor personal hygiene of food vendors, preparing food in advance, mixing raw food with cooked food, allowing food to stay at favorable bacterial growth temperatures, failure to reheat cooked foods, cross-contamination, and inadequate cleaning of equipment
• Causes of foodborne illnesses

  • Bacteria: Salmonella, Campylobacter, Enterohaemorrhagic E.coli, Listeria, Vibrio cholerae
  • Virus: Norovirus, Hepatitis A
  • Parasites: Echinococcus spp, Taenia spp, Cryptosporidium, Entamoeba histolytica, Giardia
  • Prions: infectious agents associated with neurodegenerative diseases
  • Chemicals: Naturally occurring toxins, persistent organic pollutants (POPs), heavy metals, radioactive nucleotides
• Salmonella symptoms include abdominal pain, headache, nausea, vomiting, fever, and diarrhea. Sources include domestic and wild animals and human beings. Foods involved are poultry, meat, milk, shell eggs, and other protein foods
• Shigella symptoms include fever, chills, diarrhea, and dehydration. Sources are human beings (intestinal tract) and flies. Foods involved are potatoes, tuna, shrimp, turkey, and macaroni salad, lettuce
• Staphylococcus symptoms include nausea, vomiting, dehydration. Sources are human beings (skin, nose, throat, infected sores) and animals
• E. coli symptoms include diarrhea, severe abdominal pain, nausea, vomiting, occasional fever. Sources are animals, particularly cattle, and human beings (intestinal tract). Foods involved are raw and undercooked ground beef, red meats, imported cheese
• Source of E. coli

  • Animals, particularly cattle, human beings (intestinal tract)
• Foods involved in E. coli contamination

  • Raw and undercooked ground beef and other red meats, imported cheese, unpasteurized milk
• Hepatitis A is a contagious viral disease that causes inflammation of the liver
• Contamination of food by microorganisms

  Poor personal hygiene by food handlers, contaminated water supplies, shellfish taken from sewage-contaminated water
• Improving food safety


  1. Education and information

  2. Policy formulation and enforcement

  3. Control of street food

  4. Provision of facilities

  5. Training of personnel

  6. Good environmental sanitation of food premises

  7. Inspection and certification of food

  8. Pre-engagement medical examination of staff in food premises
• Agencies responsible for food safety

  • Ministry of Health
  • Sierra Leone Standards Bureau
  • Ministry of Fisheries
  • Ministry of Agriculture
  • Freetown City Council
• Food inspection


  1. Inspection of food premises to prevent transmission of foodborne diseases

  2. Ensure food for human consumption is prepared in a clean and hygienic manner

  3. Ensure workers involved in food preparation are healthy

  4. Ensure food is prepared in a clean and healthy environment

  5. Ensure raw food products are safe
• Elements to evaluate in a food store or warehouse

  • Design of the premises (accessibility, free from sources of contamination, availability of physical facilities)
  • Hygiene status of the premises (walls, floors, drainage, ventilation, waste containers, hand washing facilities)
  • Food storage (cleanliness, temperature, air circulation, labeling of products, stacking of food)
  • Personal hygiene (staff medically examined, personal protective gear, staff training, adequate water supply)
• Inspection of restaurant/catering service, cookery shops


  Check plan and cleanliness, location of premises, adequate space, lighting and ventilation, storage facilities, water supply, liquid waste management, cloakroom, solid waste management, storage for raw and finished products, personnel appearance, medical certificate of fitness, uniforms, food handling, equipment and utensils cleanliness