What are the Dangers of Cooked Meat Left Out Overnight?

Raw chicken breasts marinating
A bowl of raw chicken breasts marinating in a bowl. (Image: Elena Elisseeva/iStock/Getty Images)

Until refrigeration became cheap and widespread in the 20th century, our forebears kept leftovers covered at room temperature in their pantries. Not surprisingly, sudden illnesses were also common in those days. In the modern era of powerful microscopes, homemakers now have the luxury of understanding the life cycle of bacteria and why it's dangerous to leave foods sitting out.

Bacteria and Other Pathogens

Bacteria and other microorganisms are all around us, every day. Only a very few, referred to collectively as pathogens, are dangerous to humans. Most of them thrive at temperatures between 40 and 140 degrees Fahrenheit, referred to as the food safety "danger zone." Below 40 F or above 140 F, bacteria struggle to survive and have little energy to spare for reproduction. At temperatures of 170 F or above, most pathogens are killed, so when your roast comes from the oven it's pretty sterile. Unfortunately, that changes quickly once its temperature drops.

Time and Temperature

Time and temperature are key factors in food safety. Once your food drops back below 140 F and into the danger zone, it quickly becomes repopulated with bacteria. Bacteria reproduce quickly and can double their population in as little as 20 minutes. The longer they have to reproduce at room temperature, the more bacteria there are in the food. It takes a certain number of bacteria, referred to as the "infective dose," to make someone sick. That number varies from species to species, but invariably the more bacteria there are, the greater the risk.

Other Risks

Bacteria and microscopic pathogens are not the only risk factors for food left out. The longer your food sits, the greater the likelihood that it will become contaminated by dust, flies, pet dander, hair, insects, rodents, curious pets or your children's unwashed hands. A more serious risk is contamination from allergens or household cleaning products, which can be quite toxic if ingested.

Proper Care

To minimize the risk of foodborne illness, always follow the food safety guidelines laid out by the USDA's Food Safety and Inspection Service. Don't let your food cool for more than a half hour at room temperature before refrigerating it. Ideally, leftover meat should be reduced to 40 F or below within two hours. Neither refrigeration or freezing kills bacteria, but both prevent them from reproducing and arriving at an infective dose. Always package your leftovers in airtight bags or containers to prevent contamination by other foods or outside elements.

REFERENCES & RESOURCES
Load comments
PARTNER & LICENSEE OF THE LIVESTRONG FOUNDATION

Copyright © 2019 Leaf Group Ltd. Use of this web site constitutes acceptance of the LIVESTRONG.COM Terms of Use, Privacy Policy and Copyright Policy. The material appearing on LIVESTRONG.COM is for educational use only. It should not be used as a substitute for professional medical advice, diagnosis or treatment. LIVESTRONG is a registered trademark of the LIVESTRONG Foundation. The LIVESTRONG Foundation and LIVESTRONG.COM do not endorse any of the products or services that are advertised on the web site. Moreover, we do not select every advertiser or advertisement that appears on the web site-many of the advertisements are served by third party advertising companies.