Viruses like Hepatitis A and Norovirus, and fungi such as molds, cause foodborne illness through contaminated food, water, or surfaces, leading to symptoms like vomiting, diarrhea, fever, and fatigue. Hepatitis A spreads via the fecal-oral route through contaminated water, ice, or pre-peeled fruits, especially in areas with poor water treatment, causing weeks of illness.

Norovirus, responsible for 40% of cases, triggers brief vomiting and diarrhea, spreads via contaminated surfaces in crowded settings like cruise ships, and survives for weeks, requiring a 1:9 bleach-to-water solution for sanitization. Molds grow deep mycelium roots, producing toxins that persist even after scraping, thriving on acidic foods or in refrigerators.

Prevent illness by washing hands thoroughly to block fecal-oral transmission, using safe water and serving food hot, and avoiding pre-peeled fruits in high-risk areas. Sanitize surfaces with a 1:9 bleach-to-water solution to eliminate Norovirus.

Discard moldy food or, for firm foods like hard cheese, cut one inch around mold cautiously. These practices—rigorous hand hygiene, safe food and water sourcing, surface sanitization, and proper mold management—are essential for food handlers to ensure consumer safety, as viruses and molds are highly persistent, pose unique risks, and demand strict adherence to safe food handling protocols to protect public health.

Read more About the lesson (Optional)

Welcome to the second lesson in the Understanding Foodborne Illness module of the Safe Food Handler Certificate course! In this lesson, you’ll explore how viruses and fungi cause foodborne illness, their transmission methods, and key prevention strategies. Let’s dive in!

Viral Foodborne Illness

Unlike bacteria, viruses do not multiply in food but inside their host by hijacking cells to replicate. They can survive on hard surfaces for up to a month or more, making them highly transmissible. Two common viral foodborne illnesses are:

• Hepatitis A: Transmitted via the fecal-oral route (unlike blood-borne Hepatitis B and C), often through contaminated food, water, or ice, especially from countries with less strict water treatment standards. Symptoms include fever, fatigue, and nausea, lasting weeks. Prevention includes:
  • Ensuring food is served piping hot.
  • Using safe drinking water and ice from reliable sources.
  • Avoiding pre-peeled fruits handled by others.
• Norovirus: Known as “Norwalk” or incorrectly “stomach flu” (not related to influenza, a respiratory illness), Norovirus causes 40% of foodborne illness cases. It leads to brief (12–24 hours) vomiting and diarrhea, spreads easily via contaminated surfaces or food, and survives on surfaces for weeks. A 1:9 bleach-to-water solution is needed to destroy it. It’s often linked to crowded settings like cruise ships.

Fungal Foodborne Illness

Fungi, including molds and yeasts, can cause foodborne illness, though yeasts rarely do. Molds are more concerning:

• Mold Growth: Molds grow like plants with deep root systems (mycelium) that produce toxins, which can cause illness. Unlike bacteria, molds thrive over a wide pH and temperature range, even on acidic foods in refrigerators.
• Safety Guidelines: Discard moldy food, as scraping off visible mold doesn’t remove deep toxins. For firm foods (e.g., hard cheese), cut at least one inch around the mold, but this is risky and not always safe.

Prevention Strategies

To prevent viral and fungal foodborne illness:

• Hand Hygiene: Wash hands thoroughly before eating or handling food to avoid fecal-oral transmission.
• Safe Food and Water: Use reliable water sources, serve hot food, and avoid pre-peeled fruits in high-risk settings.
• Surface Sanitization: Use a 1:9 bleach-to-water solution to clean surfaces contaminated by viruses like Norovirus.
• Mold Management: Discard moldy food or carefully cut around mold on firm foods, ensuring a one-inch margin.

Why This Matters

Viruses like Norovirus and molds pose unique risks due to their persistence and wide growth ranges. Proper hygiene, food handling, and surface cleaning are critical to preventing illness. Check course resources for more guidance on safe food handling practices.

Key Takeaways:

• Viruses (e.g., Hepatitis A, Norovirus) multiply in hosts, not food, and spread via the fecal-oral route or contaminated surfaces.
• Molds produce toxins in deep root systems, requiring food disposal or careful cutting on firm foods.
• Prevent illness with hand washing, safe water/food sources, and proper sanitization.