Foodborne Pathogens

Introduction

Foodborne pathogens are microorganisms that cause foodborne illnesses, which can result from consuming contaminated food or beverages. The main types of pathogens include bacteria, viruses, and parasites. Understanding these pathogens is essential for ensuring food safety and preventing disease.

Bacterial Foodborne Illnesses

Most Common Bacterial Pathogens

• Salmonella

  • Sources: Chicken, eggs, produce

  • Symptoms: Severe diarrhea, fever

  • Hospitalizations: Most common cause

  • Example: Undercooked poultry or eggs

• Clostridium perfringens

  • Source: Improperly cooked/stored food

  • Symptoms: Diarrhea, abdominal pain

• Campylobacter jejuni

  • Source: Poultry, raw milk

  • Symptoms: Diarrhea, fever

• Staphylococcus aureus

  • Source: Skin, utensils, food handlers

  • Symptoms: Nausea, vomiting

• Escherichia coli (E. coli)

  • Source: Ground meat, produce

  • Symptoms: Severe diarrhea, hemolytic uremic syndrome (HUS)

  • Strain: ETEC (O157:H7) is particularly dangerous

• Listeria monocytogenes

  • Source: Soft cheese, deli meats, milk

  • Symptoms: Fever, muscle aches, diarrhea

  • Risk: Especially dangerous during pregnancy

Comparison of Bacterial Pathogens

Viruses and Parasites

Viruses

• Norovirus

  • Most common viral foodborne illness

  • Highly contagious; causes short, intense illness

  • Source: Contaminated water, shellfish, produce

• Hepatitis A

  • Causes liver infection

  • Source: Contaminated water, food

  • Prevention: Vaccination recommended for children

Parasites

• Protozoa

  • Single-celled organisms

  • Example: Giardia, Cryptosporidium

  • Source: Contaminated water, produce

  • Symptoms: Diarrhea, abdominal pain

• Worms (Helminths)

  • Tapeworms, roundworms, flukes

  • Source: Undercooked meat, contaminated water

  • Symptoms: Vary by species; can include abdominal pain, malnutrition

Food Safety Applications

High-Risk Foods

• Raw/undercooked poultry, eggs, and meat

• Unpasteurized milk and dairy products

• Raw produce (especially leafy greens)

• Improperly stored or prepared foods

Prevention Strategies

• Cook foods to safe internal temperatures

• Wash hands and surfaces often

• Separate raw and cooked foods

• Refrigerate foods promptly

• Avoid cross-contamination

Practice Questions and Answers

• Which foodborne pathogen is the most common bacterial cause of foodborne illness? Answer: Salmonella

• Which foodborne pathogen causes the most hospitalizations? Answer: Salmonella

• Raw/undercooked milk is considered a high-risk food because of the risk of it containing pathogens. Which type of pathogen is most likely to cause foodborne illness in association with raw milk? Answer: Bacteria

Key Terms

• Pathogen: A microorganism that can cause disease.

• Foodborne illness: Sickness resulting from eating contaminated food.

• Hospitalization: Admission to a hospital for treatment due to severe illness.

• Protozoa: Single-celled parasites that can cause gastrointestinal illness.

• Helminths: Parasitic worms that infect the digestive tract.

Summary Table: Pathogen Types and Examples

Additional info:

• Foodborne illnesses can be prevented by proper food handling, cooking, and storage.

• Children, elderly, and immunocompromised individuals are at higher risk for severe outcomes.