Food Poisoning Overview Quiz

Food Poisoning Overview

• Food poisoning, also known as foodborne diseases, is an illness caused by eating contaminated food with pathogens (bacteria, molds, or viruses) or their toxins.
• Food poisoning includes foodborne intoxications and foodborne infections.

Foodborne Intoxications

• This occurs when a person consumes food or drinks that contain toxins produced by certain bacteria (e.g., Bacillus cereus, Staphylococcus aureus, Clostridium botulinum).
• Food intoxication does not involve the presence of pathogens.
• Severe cases can lead to hospitalization or death.

Foodborne Infections

• This type of poisoning occurs when consuming food containing harmful bacteria, viruses, or parasites (e.g., Salmonella, E. coli, Listeria monocytogenes).

Bacterial Food Poisoning

• Food infection: The presence of bacteria or other microbes infect the body after consumption.
• Food intoxication: Ingestion of toxins contained within the food, including bacterially produced exotoxins.

Symptoms of Food Poisoning

• Feeling sick (nausea)
• Diarrhea
• Stomach cramps
• Vomiting
• Fever
• Feeling tired or having aches and chills
• Symptoms usually begin within a few hours or days after eating contaminated food.

Microbial Toxins

• Microbial toxins are produced by microorganisms including bacteria, fungi, and algae.
• Bacterial toxins are classified into exotoxins and endotoxins.
• Exotoxins are proteins produced inside pathogenic bacteria.
• Endotoxins are lipid portions of lipopolysaccharides that compose the outer membrane of gram-negative bacteria. They are released when the bacteria die.

Bacillus cereus

• A gram-positive spore-forming foodborne pathogen.
• Causes two types of gastrointestinal illness: the emetic (vomiting) syndrome and diarrheal syndrome.
• Emetic type: Symptoms are nausea and vomiting appearing within 0.5 to 6 hours after eating contaminated food. Cereulide toxin is extremely stable.
• Diarrheal type: Characterized by watery diarrhea and abdominal pain, usually appearing 8 to 16 hours after eating contaminated food.
• B. cereus enterotoxins are acid-labile and easily destroyed by heating.

Clostridium botulinum

• A Gram-positive, rod-shaped, anaerobic, spore-forming bacteria.
• Produces botulinum toxins (A-H), some of which cause disease in humans.
• The toxins are rapidly destroyed at 100°C but resistant to enzymes in the gastrointestinal tract.
• Symptoms typically appear within 12-36 hours of exposure.
• Botulinum toxins are neurotoxic and affect the nervous system.
• Foodborne botulism symptoms include weakness, vertigo, blurred vision, dry mouth, difficulty swallowing/speaking, flaccid paralysis, no fever and no loss of consciousness.

Staphylococcus aureus

• A gram-positive, non-spore-forming cocci.
• Produces at least 14 different staphylococcal enterotoxins.
• Type A is most common in food poisoning.
• Staphylococcal food poisoning primarily due to enterotoxin intoxication.
• Causes symptoms such as nausea, vomiting, abdominal cramping (with or without diarrhea).
• Symptoms typically appear quickly (2–8 hours) after consuming contaminated food.
• Staphylococcal enterotoxins are remarkable in their heat and acid resistance.
• Often associated with dairy foods, cured meats, cheeses, pasta, sandwiches, and sausages

Salmonella

• Gram-negative, flagellated, facultative anaerobic bacilli.
• Over 1800 serovars are known.
• Often transmitted from raw or undercooked meat, poultry, eggs, raw milk, dairy products, or seafood, and food handlers.
• Symptoms: stomach pain, diarrhea, nausea, chills, fever, headache usually appearing 8-72 hours post-consumption.

Escherichia coli (E. coli)

• A Gram-negative, facultative anaerobic, rod-shaped bacterium.
• Most strains are not pathogenic, naturally found in the lower intestine.
• Virulent strains cause enteric diseases.
• Symptoms include: severe abdominal cramps, diarrhea, hemorrhagic colitis. Vomiting, sometimes fever.
• Five classes (virotypes) cause diarrheal diseases: ETEC, EIEC, EHEC, EPEC, EAEC

Listeria monocytogenes

• Gram-positive, non-spore-forming, motile, facultatively anaerobic rod-shaped bacterium.
• Found in moist environments, soil, water, decaying vegetation and animals.
• Can survive and even grow in refrigeration and other food preservation environments.
• Causes listeriosis.
• Symptoms include fever, muscle aches, nausea, vomiting, and diarrhea.
• Produces an exotoxin called Listeriolysin O toxin, which is associated with foodborne systemic illness and meningitis.