BIOL203 Lesson 10

• Each year in Canada, 4 million people get foodborne illness (1/8 people, 12.5% chance), for healthy people, risk of dying from foodborne illness is quite low
• Risk


  Measure of probability that a substance or activity will cause harm under defined conditions of exposure; Risk is dependent on behaviour
• Serious infection can lead to chronic sequelae (chronic secondary complications following an acute illness) 2-3% of foodborne disease cases
• Pathogens


  Microorganisms capable of causing a disease; some people are more susceptible than others: very young/old, pregnant women, those with compromised immune systems
• Foodborne illnesses


  Transmitted to humans through food and water; caused by eating foods contaminated with live pathogens
• Symptoms of foodborne illness include abdominal cramps, fever, vomiting, diarrhea
• Food intoxications


  Caused by eating foods containing natural toxins produced by pathogens
• Once consumed, foodborne illnesses can take 1 day to several weeks to develop; but for food intoxications, symptoms appear after a pre-formed toxin is consumed
• Foodborne bacterial pathogens

  • Campylobacter jejuni
  • Salmonella
  • Escherichia coli
  • Listeria
• Norwalk virus (Norovirus, stomach flu, winter vomiting disease)

  • Foodborne viral pathogen, highly contagious, transmitted through contaminated food, water, and human contact
  • Symptoms: vomiting, diarrhea, abdominal pain, body aches (<2 days)
• Bacterial toxin producers


  • Staphylococcus aureus: produces a toxin that makes you sick; bacteria commonly found on surface of skin --> handling food with unwashed hands is dangerous
  • Clostridium botulinum: produces botulinum, most poisonous substance known; spores are commonly found on plants and soil, pathogen grows and multiplies in absence of oxygen (often fatal, but extremely rare)
• Other microorganisms producing toxins include fungal toxins (aflatoxin) and marine toxins
• Pesticides are chemical used to control unwanted insects, weeds or fungi; they can potentially harm humans through inhalation, dermal contact, or ingestion
• Pasteurization


  Heat processing of food that inactivates some, but not all, microorganisms in food; not a sterilization process
• Other food preservation techniques

  • Heat and pressure
  • Refrigeration and freezing
  • Irradiation
• Irradiation of food involves use of low-dose radiation to kill pathogens; Health Canada regulates allowed dose to be used for spices, potatoes and flour
• Canadian agencies responsible for food safety


  • Health Canada
  • Canadian Food Inspection Agency
  • Agriculture and Agri-Food Canada
  • Environmental Bureau of Agriculture and Agri-Food Canada
  • Environment Canada
  • World Health Organization (WHO)
• Campylobacter jejuni: comes from eating undercooked meat and improperly handled poultry

  • This pathogen and Salmonella are responsible for 1.8 million infections per year, such as Guillain-Barré syndrome (GBS), reactive arthritis, and irritable bowel syndrome (IBS)
• E. coli

  • Infections occurring from improperly handled raw ground meat or eating it undercooked
• Listeria

  • Found in soil and water, it can find its way into packaged food and proliferate; It can be killed by pasteurization and cooking
• Fungal toxins: produced by fungi; aflatoxin is produced by mouldy crops and has long been known to cause liver cancer
• Marine toxins: can accumulate in some fish; most known is toxic red tides along the Gulf of Mexico