Pizza should not be left out at room temperature for more than 2 hours to remain safe to eat. The USDA and food safety experts recommend the "2-hour rule" because pizza is a perishable food that can harbor bacteria such as Staphylococcus aureus, E. coli, and Campylobacter when kept in the temperature "danger zone" between 40°F and 140°F (4°C to 60°C)
. If the ambient temperature is above 90°F (32°C), the safe time to leave pizza out reduces to just 1 hour due to faster bacterial growth
. Bacteria can double in number every 20 minutes in this danger zone, significantly increasing the risk of foodborne illness
. Eating pizza left out overnight or for many hours beyond the 2-hour limit increases the risk of symptoms like nausea, vomiting, stomach pain, diarrhea, and fever, which can appear within hours to days after consumption
. While some people report eating pizza left out longer without immediate illness, this is risky and not recommended because foodborne illness depends on bacterial load and individual susceptibility
. To keep pizza safe, refrigerate leftovers within 2 hours in an airtight container and reheat to an internal temperature of 165°F (74°C) before eating
. In summary:
- Maximum safe time at room temperature: 2 hours
- If above 90°F (32°C): 1 hour
- Beyond this, risk of foodborne illness increases sharply
- Refrigerate leftovers promptly and reheat thoroughly before eating
This guidance applies to all types of pizza, including those with cheese, sauce, and various toppings, which are all prone to bacterial growth
