Dive into how bacteria grow exponentially, doubling every 15 to 20 minutes under ideal conditions like room temperature, potentially reaching over 1 billion in 10 hours on leftover chicken left out since this afternoon. Potentially hazardous foods, rich in protein, with a neutral pH above 4.5 and high moisture, create the perfect environment for this rapid multiplication, making them prone to contamination. To prevent foodborne illness, keep these foods out of the danger zone (4 degrees Celsius to 60 degrees Celsius) for no more than two hours by controlling at least one of the FAT-TOM conditions—Food, Acidity, Time, Temperature, Oxygen, or Moisture.

This includes refrigerating promptly at or below 4 degrees Celsius or cooking to safe temperatures above 60 degrees Celsius. Mishandling can lead to dangerous bacterial levels, posing serious health risks, so always follow safe practices and refer to course resources for detailed guidance on proper storage and preparation techniques.

Read more About the lesson (Optional)

Welcome to the seventh lesson in the Understanding Microorganisms module of the Safe Food Handler Certificate course! In this lesson, you’ll learn how quickly pathogenic bacteria can multiply through exponential growth and why potentially hazardous foods require careful handling to prevent foodborne illness. Let’s get started!

Exponential Growth of Bacteria

Bacteria grow by dividing in two, a process called exponential growth. One bacterium becomes two, two become four, and so on. Under ideal conditions, bacteria can double every 15 to 20 minutes. For example:

• If one pathogenic bacterium is left on leftover chicken at room temperature for 10 hours, it can multiply to over 1 billion bacteria. This rapid growth shows how quickly a small contamination can reach illness-causing levels.
• To prevent this, potentially hazardous foods must not be left at room temperature for more than two hours, as bacteria thrive in the danger zone (4°C to 60°C).

Potentially Hazardous Foods

Potentially hazardous foods are more likely to support rapid bacterial growth because they have three key characteristics:

• High Protein: Foods like meats, dairy, and eggs provide nutrients for bacteria.
• Neutral pH: Foods with a pH above 4.5 (e.g., meats, dairy, vegetables) are ideal for bacterial growth.
• High Moisture: Foods with available water support bacterial multiplication.

Food handlers should always ask, “Is this a potentially hazardous food?” If yes, apply the barrier method by controlling at least one of the six FAT-TOM conditions (Food, Acidity, Time, Temperature, Oxygen, Moisture) to prevent bacterial growth.

Why This Matters

The exponential growth of bacteria highlights the importance of strict time and temperature controls for potentially hazardous foods. Leaving food out too long can lead to dangerous bacterial levels, causing foodborne illness. Check course resources for more guidance on safe handling practices.

Key Takeaways:

• Bacteria grow exponentially, doubling every 15 to 20 minutes, potentially reaching 1 billion in 10 hours.
• Potentially hazardous foods are high in protein, have a neutral pH (above 4.5), and high moisture, making them ideal for bacterial growth.
• Keep potentially hazardous foods at room temperature for no more than two hours to prevent illness.