What is potentially hazardous food FDA?

November 13, 2025 •

3 min read

According to research published on the FDA website, improper cooling is one of the top contributors to foodborne illness, highlighting the critical importance of understanding what is potentially hazardous food FDA and how to control it. These are foods that require strict time and temperature control to limit the growth of harmful bacteria and prevent sickness.

Quick Summary

Potentially hazardous foods, now termed Time/Temperature Control for Safety (TCS) foods by the FDA, require strict management of temperature and time to prevent microbial growth and toxin formation. Proper handling is essential for limiting the growth of pathogens that cause foodborne illnesses. These foods have specific characteristics that make them ideal for bacterial proliferation.

Key Points

TCS Foods Defined: The FDA now refers to potentially hazardous food (PHF) as Time/Temperature Control for Safety (TCS) food, which requires specific temperature management.
Temperature Danger Zone: The critical temperature range for bacterial growth is 41°F to 135°F (5°C to 57°C), where TCS foods should spend a minimum amount of time.
The 4-Hour Rule: TCS foods held in the danger zone for more than four hours must be discarded to prevent foodborne illness.
Proper Cooling is Critical: Hot TCS foods must be cooled from 135°F to 70°F within two hours, then to 41°F or below within an additional four hours.
Control Cross-Contamination: Always separate raw TCS foods from ready-to-eat items during preparation and storage to avoid transferring harmful bacteria.
Use a Food Thermometer: An accurate food thermometer is essential for verifying that food is cooked to safe internal temperatures and is held at proper hot/cold holding temperatures.

Defining Potentially Hazardous Food (PHF)

In the United States, the Food and Drug Administration (FDA) has historically defined Potentially Hazardous Food (PHF) as a food that is capable of supporting the rapid and progressive growth of infectious or toxigenic microorganisms. However, modern terminology found in the FDA Food Code now refers to these items as "Time/Temperature Control for Safety" (TCS) foods. The core principle remains the same: these foods require specific controls over time and temperature to limit pathogenic growth or toxin formation, which are key to preventing foodborne illness.

Key characteristics that make a food potentially hazardous include its moisture content (water activity), pH level, and nutritional profile. Bacteria thrive in environments that offer a good balance of these factors, making items like meat, dairy, and cooked grains susceptible to rapid microbial growth if not managed correctly.

The Temperature Danger Zone and Time Control

Controlling the temperature of TCS foods is the most effective way to ensure their safety. The FDA defines the "Temperature Danger Zone" as the range between 41°F and 135°F (5°C and 57°C). Within this range, bacteria can multiply rapidly, potentially doubling in number in as little as 20 minutes. To protect consumers, food handlers must minimize the time these foods spend in this danger zone. Regulations typically require that cold TCS foods are held at or below 41°F, and hot TCS foods are held at or above 135°F.

For situations where time control is used instead of temperature, such as during preparation or display, the FDA guidelines often reference the "4-hour rule." For ready-to-eat TCS food that is held between 41°F and 135°F:

If it is held for less than two hours, it can be refrigerated or used immediately.
If it is held for between two and four hours, it can be used immediately but cannot be put back in refrigeration.
If it is held for four hours or longer, it must be discarded.

Proper Handling and Cooling Procedures

Effective management of TCS foods goes beyond simple storage. It involves a comprehensive approach to food handling, including cooking, cooling, and reheating. The FDA Food Code provides specific guidelines to ensure safety throughout the entire food preparation process.

Cooling Hot Foods

One of the most critical steps is cooling cooked TCS foods. Improper cooling is a leading cause of foodborne illness, as it allows bacteria to proliferate in the temperature danger zone for extended periods. The FDA-recommended two-stage cooling process is as follows:

Cool the food from 135°F to 70°F within two hours or less.
Cool the food from 70°F to 41°F or below within an additional four hours.

To facilitate this rapid cooling, large batches of food should be divided into smaller or thinner portions and placed in shallow pans or ice baths.

Reheating Foods

When reheating TCS foods for hot holding, they must be rapidly heated to a minimum internal temperature of 165°F for at least 15 seconds. This must be achieved within two hours. Warming trays and other hot-holding equipment should not be used for reheating, as they do not raise the temperature quickly enough to be safe.

Preventing Cross-Contamination

Raw TCS foods often contain pathogens that can be transferred to ready-to-eat foods. To prevent this, strict separation is necessary. This includes using separate cutting boards and utensils for raw and cooked foods and storing raw meat below other items in the refrigerator to prevent dripping.

Comparison Table: PHF/TCS vs. Non-PHF Foods


Characteristic	PHF/TCS Foods	Non-PHF/Non-TCS Foods
Moisture (Water Activity)	High (>0.85)	Low (<0.85)
pH Level	Neutral to slightly acidic (4.6-7.5)	High acid (<4.6)
Nutrient Content	High in protein and carbohydrates	Low nutrient content
Storage Requirement	Requires strict temperature control	Safe at room temperature
Examples	Raw meat, dairy products, cooked rice, cut melons	Dry goods, canned goods, popcorn, potato chips

Conclusion

Understanding what is potentially hazardous food FDA is the foundation of preventing foodborne illness. By properly identifying TCS foods and adhering to strict time and temperature control guidelines, both at home and in commercial settings, the risk of pathogen growth can be significantly minimized. Employing best practices for cooking, cooling, and handling these foods is crucial for ensuring the health and safety of anyone consuming them. Awareness of these food safety principles empowers individuals to make informed choices and take the necessary precautions to avoid contamination and sickness.

For more detailed information, consult the official FDA Food Code at the FDA website.

Frequently Asked Questions

TCS stands for Time/Temperature Control for Safety food. This is the modern FDA term for what was previously called potentially hazardous food (PHF), indicating that it requires specific temperature and time management to remain safe.

Foods are considered potentially hazardous when they have a high moisture content, a pH level between 4.6 and 7.5, and are rich in nutrients like protein and carbohydrates, as these conditions are ideal for bacterial growth.

The Temperature Danger Zone is the temperature range between 41°F and 135°F (5°C and 57°C). In this zone, bacteria that cause foodborne illness can multiply rapidly to dangerous levels.

According to the 4-hour rule, TCS food can be safely held within the temperature danger zone for a cumulative maximum of four hours. After four hours, the food must be discarded.

Examples of TCS foods include dairy products, eggs, meat, poultry, seafood, cooked rice, cooked pasta, cut melons, and raw seed sprouts.

To cool food safely, you must reduce its temperature from 135°F to 70°F within two hours, and then to 41°F or below within the next four hours. This can be done by dividing it into smaller portions, using shallow containers, or placing it in an ice bath.

When reheating TCS foods for hot holding, they must be rapidly heated to a minimum internal temperature of 165°F for 15 seconds within a two-hour timeframe.