Understanding the FATTOM Principles
The most effective way to prevent food poisoning is to control the conditions that bacteria need to multiply. The acronym FATTOM is a simple and memorable way to recall these six critical requirements: Food, Acidity, Time, Temperature, Oxygen, and Moisture. By understanding and managing each of these elements, you can significantly reduce the risk of foodborne illness in your home and business.
F: Food (Nutrients)
Bacteria, like all living organisms, need a food source to grow and reproduce. They are not picky eaters, and most foodborne pathogens will thrive on the nutrients found in many common food items. Foods rich in proteins and carbohydrates are particularly susceptible to bacterial growth.
- High-Risk Foods: These include meats, poultry, seafood, dairy products, eggs, and cooked rice and pasta.
- How to Control: Proper storage and handling are key. Never leave these foods unrefrigerated for extended periods.
A: Acidity (pH Levels)
Most food poisoning bacteria prefer a neutral or slightly acidic environment to grow, typically with a pH range of 4.6 to 7.0. Highly acidic foods, such as pickles, lemons, and vinegars, naturally inhibit bacterial growth.
- How to Control: Lowering the pH of food can be an effective preservation method. This is why many foods are pickled or fermented, creating an acidic environment where most bacteria cannot survive.
T: Time
Under ideal conditions, food poisoning bacteria can multiply to dangerous levels in a relatively short period. Some bacteria can double their population every 15 to 30 minutes in the right environment.
- The 2-Hour Rule: Perishable foods should not be left in the temperature danger zone for more than two hours. If the ambient temperature is above 90°F (32°C), this time is reduced to just one hour.
T: Temperature
This is arguably the most critical factor for controlling bacterial growth. The temperature danger zone is the range where bacteria multiply most rapidly.
- Temperature Danger Zone: 40°F to 140°F (4°C to 60°C).
- How to Control: Keep hot foods hot (above 140°F/60°C) and cold foods cold (below 40°F/4°C). This stops or significantly slows down bacterial multiplication.
O: Oxygen
The oxygen requirements of food poisoning bacteria vary. Some, known as aerobes, need oxygen to grow, while others, anaerobes, thrive in its absence. Still others, called facultative anaerobes, can survive in either condition.
- Anaerobic Bacteria: An example is Clostridium botulinum, which causes botulism and can grow in improperly canned foods where oxygen is scarce.
- How to Control: Proper sealing and packaging methods, like vacuum-packing, can control oxygen levels to inhibit specific bacteria.
M: Moisture (Water Activity)
Bacteria need water to grow and survive. Water activity (aw) measures the amount of free, unbound water available for bacterial growth.
- Water Activity Requirements: Most bacteria need an aw of 0.91 or higher to multiply. Drying or adding solutes like sugar and salt decreases water activity, which is why jams and jerky last longer.
Comparison of Key Bacterial Requirements
| Requirement | Favorable Condition for Bacteria | Control Measure for Prevention |
|---|---|---|
| Food (Nutrients) | Foods rich in protein and carbohydrates, such as meat, dairy, and cooked grains. | Refrigerate perishable foods, use fresh ingredients, and avoid cross-contamination during preparation. |
| Acidity (pH) | A neutral to slightly acidic pH range (4.6 to 7.0). | Store acidic foods safely, and use acidification methods (e.g., vinegar) to preserve some foods. |
| Time | Extended periods spent in the temperature danger zone. | Follow the two-hour rule for keeping perishable foods out at room temperature. |
| Temperature | Temperatures between 40°F and 140°F (4°C to 60°C), the 'danger zone'. | Keep cold food cold (≤40°F/4°C) and hot food hot (≥140°F/60°C). |
| Oxygen | Depends on the bacteria; some need oxygen (aerobic), some don't (anaerobic). | Use appropriate packaging (airtight or vacuum-sealed) for different food types to control oxygen exposure. |
| Moisture | High water activity (above 0.91) in food, indicating free water is available. | Use drying, salting, or sugaring to lower water activity in food items. |
Specific Bacterial Examples
Different food poisoning bacteria have specific sensitivities and growth preferences. For example, Listeria monocytogenes is a notable exception that can grow slowly at refrigeration temperatures (below 40°F/4°C), making proper temperature control especially critical for ready-to-eat deli meats and cheeses. In contrast, Clostridium botulinum spores can survive high heat and thrive in low-oxygen environments, which is why safe canning practices are crucial. Salmonella and E. coli are two of the most common causes of foodborne illness in the U.S., found in undercooked poultry, meat, and contaminated produce, underscoring the importance of proper cooking and avoiding cross-contamination.
Conclusion: Your Role in Food Safety
Controlling the requirements for the growth of food poisoning bacteria is not a passive responsibility; it requires active measures. By mastering the principles of FATTOM, you empower yourself to prevent the conditions that lead to bacterial proliferation. Simple, consistent actions—like proper handwashing, separating raw from cooked foods, cooking to the right temperature, and chilling foods promptly—can make all the difference in safeguarding your health and the health of those you feed. Food safety is a shared responsibility, and every individual plays a vital role in minimizing the risk of foodborne illnesses in their community.
References
- Food Safety Net Services. (2024). FATTOM: A Key to Microbial Control and Food Safety.
- World Health Organization. (2024). Food safety.
- Centers for Disease Control and Prevention. (2024). About Four Steps to Food Safety.
- U.S. Department of Agriculture. (2024). Keep Food Safe: Food Safety and Inspection Service.
