Key Takeaways
- Temperature danger zone is 41°F to 135°F
- Bacteria can double every 20 minutes in the danger zone
- TCS food cannot be in the danger zone more than 4 hours total
- Two-stage cooling: 135°F to 70°F in 2 hours, then 70°F to 41°F in 4 more hours
- Use ice baths, shallow pans, and smaller portions to cool food quickly
2.1 The Temperature Danger Zone
Temperature control is one of the most critical aspects of food safety. Bacteria grow rapidly in certain temperature ranges, making proper temperature control essential.
What Is the Danger Zone?
Temperature Danger Zone: 41°F to 135°F (5°C to 57°C)
This is the temperature range where bacteria multiply most rapidly. Within this zone, harmful bacteria can double in number every 20 minutes under ideal conditions.
Why These Temperatures?
| Temperature | What Happens |
|---|---|
| Below 41°F | Bacteria growth slows significantly (safe cold holding) |
| 41°F to 135°F | DANGER ZONE - Bacteria multiply rapidly |
| Above 135°F | Bacteria growth stops (safe hot holding) |
| 165°F+ | Most bacteria are killed (cooking temperatures) |
The 4-Hour Rule
TCS foods should NOT be in the temperature danger zone for more than 4 hours total.
This includes:
- Time during receiving
- Time during storage
- Time during preparation
- Time during cooking
- Time during holding
- Time during service
If TCS food has been in the danger zone for more than 4 hours, it must be discarded.
Two-Stage Cooling
When cooling hot food, it must pass through the danger zone quickly:
Stage 1: Cool from 135°F to 70°F within 2 hours
Stage 2: Cool from 70°F to 41°F within 4 additional hours
Total cooling time: 6 hours maximum
For the Exam: Remember "2 then 4" for cooling. If you can't reach 70°F in 2 hours, the food must be reheated to 165°F and start cooling again.
Methods to Cool Food Quickly
- Ice bath - Surround container with ice water and stir
- Ice paddle - Stir with hollow paddle filled with ice
- Shallow pans - Divide into portions less than 2 inches deep
- Ice as ingredient - Add ice directly to soups/stews
- Blast chiller - Specialized rapid cooling equipment
- Smaller portions - Divide large items into smaller pieces
What is the temperature danger zone?
How quickly can bacteria double in number within the danger zone?
What is the maximum total time TCS food can be in the temperature danger zone?
When cooling hot food, what temperature must it reach within the first 2 hours?