Temperature Danger Zone
The Temperature Danger Zone is the temperature range between 41°F and 135°F (5°C to 57°C) in which foodborne bacteria grow most rapidly, potentially doubling in number every 20 minutes. TCS foods must be kept out of this range to prevent foodborne illness.
Exam Tip
Temperature Danger Zone = 41°F to 135°F. Bacteria double every 20 minutes in this range. 4-hour rule: discard food after 4 total hours in the zone. Two-stage cooling: 135°F to 70°F in 2 hours, then 70°F to 41°F in 4 more hours. This is THE most tested concept on ServSafe.
What Is the Temperature Danger Zone?
The Temperature Danger Zone is the critical temperature range where pathogenic bacteria can grow rapidly in Time/Temperature Control for Safety (TCS) foods. Food left in this zone for extended periods becomes unsafe to eat and must be discarded.
Temperature Danger Zone Range
| Boundary | Temperature | Significance |
|---|---|---|
| Upper limit | 135°F (57°C) | Minimum hot holding temperature |
| Lower limit | 41°F (5°C) | Maximum cold holding temperature |
| Most rapid growth | 70°F - 125°F (21°C - 52°C) | Bacteria multiply fastest in this range |
Critical Temperature Benchmarks
| Temperature | Application |
|---|---|
| 165°F (74°C) | Poultry, stuffing, reheated leftovers (15 seconds) |
| 155°F (68°C) | Ground meats, injected meats, eggs for hot holding (15 seconds) |
| 145°F (63°C) | Whole cuts of meat, fish, shell eggs for immediate service (15 seconds) |
| 135°F (57°C) | Minimum hot holding; fruits, vegetables, grains, legumes for hot holding |
| 70°F (21°C) | Food must cool from 135°F to 70°F within 2 hours |
| 41°F (5°C) | Maximum cold holding; food must cool from 70°F to 41°F within 4 hours |
| 0°F (-18°C) | Frozen food storage |
The 4-Hour Rule
| Time in Danger Zone | Action Required |
|---|---|
| 0-2 hours | Safe to serve, reheat, or refrigerate |
| 2-4 hours | Must be served immediately or discarded |
| Over 4 hours | Must be discarded — cannot be saved |
Two-Stage Cooling Method
| Stage | Requirement | Time Allowed |
|---|---|---|
| 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 | 135°F to 41°F | Within 6 hours total |
If food does not reach 70°F within 2 hours, it must be reheated to 165°F and the cooling process restarted or the food must be discarded.
Common Violations
- Leaving cooked food on the counter to cool
- Holding food at room temperature during service without temperature controls
- Placing large pots of hot food directly in the refrigerator without cooling first
- Failing to monitor holding temperatures during buffet service
Exam Alert
The Temperature Danger Zone (41°F to 135°F) is the single most important concept on the ServSafe exam. Know all four cooking temperature tiers, the two-stage cooling method, and the 4-hour total accumulation rule. Food that has been in the danger zone for more than 4 hours total must be DISCARDED.
Study This Term In
Related Terms
TCS Foods (Time/Temperature Control for Safety)
TCS foods are foods that require time and temperature control for safety to limit the growth of pathogenic microorganisms or toxin formation. These foods are high in moisture, protein, and have a neutral to slightly acidic pH, making them ideal environments for bacterial growth.
Big Six Pathogens
The Big Six pathogens are six highly infectious microorganisms identified by the FDA Food Code that require food workers to be excluded from or restricted in food service operations when diagnosed: Norovirus, Hepatitis A, Salmonella Typhi, Shigella spp., Shiga toxin-producing E. coli (STEC), and non-typhoidal Salmonella.
Foodborne Illness
A foodborne illness (food poisoning) is a disease transmitted to people through contaminated food or beverages, caused by biological hazards (bacteria, viruses, parasites), chemical hazards (toxins, cleaning agents), or physical hazards (foreign objects). The CDC estimates 48 million cases occur annually in the United States.
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