Microorganisms can contaminate food through environmental sources like dust and soil, and through food handlers themselves. Dust can carry bacteria, so food must be covered, and vegetables from soil should be washed thoroughly. Food handlers can spread pathogens either by being sick (infection) or by carrying bacteria like Staphylococcus aureus on their skin or nose (colonization). Poor hand hygiene allows these microbes to transfer to food. Staph is especially dangerous—it can cause vomiting within 30 minutes, and its toxin is heat-resistant. A real-life outbreak at a food fair showed this clearly: a handler with poor hygiene contaminated a burger topping, which was then left at unsafe temperatures, allowing Staph to multiply. Reheating couldn’t destroy the toxin, and hundreds got sick. The key lessons are simple but critical: always wash hands thoroughly before handling food or after touching your body, and discard any food left in the danger zone too long, because cooking won’t make it safe again. Following these steps is essential to prevent foodborne illness and protect public health.
Read more About the lesson (Optional)
Welcome to the second lesson in the Understanding Microorganisms module of the Safe Food Handler Certificate course! In this lesson, you’ll learn how microorganisms get into our food, the role food handlers play in contamination, and key lessons from a real-world outbreak. Let’s dive in and keep those food safety capes on!
How Microorganisms Contaminate Food
Microorganisms don’t magically appear in food—they come from specific sources. Here are some common ways they end up in our meals:
- Environmental Sources:
- Dust: Dust can carry bacteria, so the Provincial Food Safety Regulation requires all food on display or in storage to be covered to prevent contamination.
- Soil: Vegetables grown in soil can harbor microorganisms. Wash them thoroughly with a scrub brush, and take extra care when home-canning to avoid contamination.
- Food Handlers:
Food handlers can introduce microorganisms in two main ways:- Infection: If a food handler is sick with a pathogen (e.g., experiencing symptoms like diarrhea or vomiting), poor hand hygiene can transfer those pathogens to food.
- Colonization: Some bacteria, like Staphylococcus aureus (commonly called Staph), live on the skin, scalp, or inside the nose of healthy people without causing illness. These bacteria can contaminate food if a food handler touches their body and then handles food without washing their hands properly.
The Dangers of Staphylococcus aureus (Staph)
Staphylococcus aureus is a common pathogenic bacterium found on the skin of about half the population at any given time. If it contaminates food and produces its toxin, it can cause vomiting within as little as 30 minutes. Staph outbreaks are often linked to poor hand hygiene among food handlers.
Case Study: A Fair Outbreak
At a large food fair, hundreds of people became violently ill with vomiting just hours after eating a novelty food item, a “cronut burger.” Investigations revealed that a food handler with poor hand hygiene contaminated one of the burger toppings days before the event. The handler likely touched their body, transferring Staph bacteria to the food. The contaminated topping was left in the danger zone (temperatures where bacteria thrive) for over two hours, allowing Staph to multiply and produce its heat-stable toxin. Even later cooking or reheating couldn’t destroy the toxin, leading to the outbreak.
Lessons Learned
This outbreak highlighted two critical food safety rules:
- Wash Hands Thoroughly: Always wash your hands before handling food and after touching your body (e.g., face, hair, or nose) to prevent contamination.
- Discard Temperature-Abused Food: If potentially hazardous food has been left in the danger zone for too long, it’s considered contaminated. No amount of cooking can make it safe—discard it immediately.
Why This Matters
Understanding how microorganisms get into food helps you prevent contamination and protect customers. Proper hand hygiene and temperature control are key to stopping pathogens like Staph from causing foodborne illness. Always follow the Provincial Food Safety Regulation and check course resources for more guidance.
Key Takeaways:
- Microorganisms come from environmental sources (dust, soil) and food handlers (via infection or colonization).
- Staphylococcus aureus can cause rapid illness if food is contaminated due to poor hand hygiene.
- Wash hands thoroughly and discard temperature-abused food to prevent outbreaks.