Quick Answer
It is not recommended to eat a hamburger that has been left out at room temperature overnight. Cooked ground beef should be discarded if left out for more than 2 hours at temperatures above 40°F. Bacteria can grow rapidly on cooked hamburgers, potentially leading to foodborne illness. Reheating the patty thoroughly may kill bacteria but does not eliminate the risk. For food safety, it is best to throw out cooked hamburgers that have sat at room temperature overnight.
What happens when you leave a cooked hamburger out overnight?
Leaving cooked hamburgers out at room temperature overnight allows bacteria like E. coli and Salmonella to grow to dangerous levels. These bacteria are killed during the cooking process but can quickly multiply once the patty cools. Bacteria thrive in the “danger zone” between 40°F and 140°F and can double in number every 20 minutes. Overnight, the hamburger passes through the danger zone for several hours, allowing bacterial levels to climb exponentially to potentially hazardous levels.
Is it safe to reheat and eat a hamburger left out overnight?
Although thoroughly reheating a hamburger left out overnight may kill any bacteria present, it does not necessarily make it safe to eat. Some bacteria produce heat-stable toxins that cannot be destroyed through cooking. If bacterial levels were high after sitting out overnight, the toxins will remain in the patty even after reheating. These toxins can still cause food poisoning. So while the bacteria may be dead, preformed toxins could make you sick if you eat the hamburger.
What are the risks of eating a hamburger left out overnight?
Eating a hamburger left at room temperature overnight poses a risk of contracting a foodborne illness. Potential dangers include:
- Salmonella – Causes diarrhea, fever, stomach cramps, and dehydration.
- E. coli – Can lead to severe stomach cramps, bloody diarrhea, vomiting, and fever.
- Listeria monocytogenes – May cause fever, muscle aches, nausea, and diarrhea.
- Staphylococcus aureus – Leads to nauseousness, vomiting, stomach cramps, and diarrhea.
Symptoms typically start within 1 to 3 days after eating contaminated food. Food poisoning can be life-threatening in certain groups like the elderly, pregnant women, young children, and those with compromised immune systems.
How long can cooked hamburgers be left at room temperature?
The United States Department of Agriculture Food Safety and Inspection Service recommends discarding cooked hamburgers left out for longer than 2 hours at temperatures above 40°F. Bacteria multiply rapidly in the danger zone and the 2-hour rule helps limit growth. Cooked hamburgers should also never sit out for more than 1 hour in temperatures above 90°F. If the weather is hot, the USDA suggests throwing out food left out for only 1 hour.
Tips to keep cooked hamburgers safe
To prevent foodborne illness from cooked hamburgers, follow these food safety recommendations:
- Refrigerate patties within 2 hours of cooking.
- Store cooked burgers in shallow containers to allow rapid cooling.
- Divide large quantities into smaller portions before refrigerating.
- Keep cooked meats separate from raw meats in the fridge.
- Discard any hamburgers left in the danger zone for over 2 hours.
- When reheating, cook patties to an internal temperature of at least 165°F.
Conclusion
Eating a hamburger left out on the counter overnight creates an opportunity for bacteria like Salmonella and E. coli to multiply to unsafe levels. Even if you reheat the patty thoroughly, toxins left behind by bacteria could still cause food poisoning. The USDA recommends throwing away cooked ground beef within 2 hours to prevent illness. Leftover hamburgers should always be refrigerated promptly in shallow containers. Following basic food safety rules will help protect you from risks of eating a hamburger left out too long at room temperature.
References
Hamburger Left Out Overnight – Is It Still Good?
U.S. Department of Agriculture Food Safety and Inspection Service. (2013, November). Danger Zone (40°F – 140°F). Retrieved from https://www.fsis.usda.gov/wps/portal/fsis/topics/food-safety-education/get-answers/food-safety-fact-sheets/safe-food-handling/danger-zone-40-f-140-f/CT_Index
U.S. Department of Agriculture Food Safety and Inspection Service. (2013, August). Basics for Handling Food Safely. Retrieved from https://www.fsis.usda.gov/wps/wcm/connect/fsis-content/internet/main/topics/food-safety-education/get-answers/food-safety-fact-sheets/safe-food-handling/basics-for-handling-food-safely/ct_index
U.S. Department of Agriculture Food Safety and Inspection Service. (2013, June). Food Safety While Hiking, Camping & Boating. Retrieved from https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/food-safety-while-hiking-camping-boating
Centers for Disease Control and Prevention. (2018, July). Food Safety. Retrieved from https://www.cdc.gov/foodsafety/food-poisoning.html
Washington State Department of Health. (2012, June). Food Safety Myths. Retrieved from https://www.doh.wa.gov/CommunityandEnvironment/Food/FoodWorkerandIndustry/FoodSafetyMyths
Utah Department of Health. (n.d.). Food Safety Facts – Power Outages, Flooding, and Storms. Retrieved from https://health.utah.gov/epi/community/foodsafety/PowerOutage.pdf
How Long Can Hamburgers Sit Out?
U.S. Department of Agriculture Food Safety and Inspection Service. (2021, April). Leftovers and Food Safety. Retrieved from https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/leftovers-and-food-safety
FDA. (2017, November). Refrigerator Thermometers: Cold Facts about Food Safety. Retrieved from https://www.fda.gov/consumers/consumer-updates/refrigerator-thermometers-cold-facts-about-food-safety
Centers for Disease Control and Prevention. (2019, July). Keep Food and Water Safe after a Disaster. Retrieved from https://www.cdc.gov/disasters/foodwater/facts.html
U.S. Department of Agriculture Food Safety and Inspection Service. (2013, June). Be Food Safe: Protect Yourself from Food Poisoning. Retrieved from
https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/be-food-safe-protect-yourself-food-poisoning
Academy of Nutrition and Dietetics. (2019, October). How Long Can Food Be Left Out? Retrieved from https://www.eatright.org/homefoodsafety/four-steps/refrigerate/how-long-can-food-be-left-out
Dangers of Eating Old Hamburgers
Centers for Disease Control and Prevention. (2018, May). Burger. Restaurant Burger. Dangerous Burger. Retrieved from https://www.cdc.gov/features/burgerpreparation/index.html
U.S. Department of Health & Human Services. (n.d.). Food Poisoning and Foodborne Illness. Retrieved from https://www.foodsafety.gov/food-poisoning
Centers for Disease Control and Prevention. (2018, May). Estimates of Foodborne Illness in the United States. Retrieved from https://www.cdc.gov/foodborneburden/estimates-overview.html
Mayo Clinic. (2019, August). Food poisoning. Retrieved from https://www.mayoclinic.org/diseases-conditions/food-poisoning/symptoms-causes/syc-20356230
Academy of Nutrition and Dietetics. (2019, October). Food Safety Mistakes You Don’t Know You’re Making. Retrieved from https://www.eatright.org/homefoodsafety/four-steps/mistakes-you-dont-know-youre-making
Properly Storing Cooked Hamburgers
U.S. Department of Agriculture Food Safety and Inspection Service. (2013, December). Safe Food Handling: What You Need to Know. Retrieved from https://www.fsis.usda.gov/wps/wcm/connect/a87cdc2c-6ddd-49f0-bd1f-393086742e68/Safe_Food_Handling.pdf?MOD=AJPERES
U.S. Department of Agriculture Food Safety and Inspection Service. (2013, April). Kitchen Companion: Your Safe Food Handbook. Retrieved from https://www.fsis.usda.gov/wps/wcm/connect/960c02b4-0025-4e1a-967f-393586742e68/Kitchen_Companion.pdf?MOD=AJPERES
Academy of Nutrition and Dietetics. (2020, February). Food Safety Recommendations for People with Cancer. Retrieved from https://www.eatright.org/health/wellness/healthy-aging/food-safety-recommendations-for-people-with-cancer
Utah Department of Health. (n.d.). Food Safety Facts – Taking Food Home from a Restaurant. Retrieved from https://health.utah.gov/epi/community/foodsafety/HomeFromRestaurant.pdf
FoodSafety.gov. (n.d.). Safe Food Handling: What You Need to Know. Retrieved from https://www.foodsafety.gov/keep/basics/index.html