Is a Big Mac Safe to Eat if it Was Left Out Overnight?

Big Mac hamburger, fries, and drink in McDonald's cup on tray.
Big Mac hamburger, fries, and drink in McDonald’s cup on tray.

We’ve all heard of that Big Mac that looks nearly identical after over a decade of being left out. Does that mean we can eat one that’s been left out overnight?

Although the USDA recommends that foods should not be eaten after 2 hours of sitting at room temperature, a Big Mac is lower in moisture and doesn’t contain highly perishable ingredients like milk and eggs. It may be safe after one night but always err on the side of caution with food safety.

The decade-old Big Mac might not have had mold, but that doesn’t mean that they’ll still be safe to eat. I’ve been there. As a broke college student, I suddenly became willing to eat foods that were questionably old.

It’s important to take stock of the cleanliness of your home, if the Big Mac was covered, and the humidity of your home. In general, because of the lack of moisture in a Big Mac, they’re still good after a night of being left out in the box.

USDA Food Saftey Guidelines

The USDA doesn’t just consider the development of mold, or funky smells coming from foods.

The USDA uses analysis of the growth of different bacterias to know when a food has really gone bad. The presence of too many of these bacteria will cause sickness that ranges from slight to excruciating.

The USDA tends to give guidelines that are on the safest side that we can be on. These guidelines are specially meant for restaurants and food handlers. They protect these establishments from the liability that comes with harming customers with bad food.

The best way to do this is to handle food in such a way that it’s not even close to being bad. To learn more about specific kinds of bacteria and see the most up-to-date information check out the USDA’s website.

Bacteria “Danger Zone”

The USDA specifies that within the range of 40-140 degrees Fahrenheit certain foods are in the bacteria danger zone. This applies especially to foods high in moisture, dairy products, or proteins that haven’t been cooked. That includes raw eggs and raw meat.

They recommend that food that is stored over a longer period of time than 2 hours should be kept below 40 or above 140 degrees Fahrenheit.

How Clean is Your Space?

The USDA specifies another important clarification for food safety is keeping the handling of the food as clean as possible. Where’s your Big Mac at? Is it still in the box? Is it on a semi-clean plate? Is the counter clean that it’s on? These are all important things to consider.

A Big Mac might not have a tendency to grow a lot of bacteria, but if it’s exposed to an environment that will introduce a lot of bacteria, this can become problematic.

Two hamburgers and a cup of drink served on a dark wooden table.
Two hamburgers and a cup of drink served on a dark wooden table.

Big Mac Breakdown

Let’s take a look at what’s in a Big Mac and how that affects the stability of the food. Some things to recognize: some things act as natural preservatives. Fats and salt will last a long time when left out.

What does fast food have a lot of? You guessed it, fat and salt! That’s not even counting McDonald’s’ proprietary blend of wonderful preservatives and colorings that help those burgers stay pretty after years of being left out.

Moisture Levels

Now, don’t be too quick to judge McDonald’s and swear off fast food altogether, just for a famous social media gimmick. There are many other reasons to dislike fast food and use some of our articles to make some amazing food for yourself!

Part of the reason that these burgers will last so long is that they have very low moisture content in the first place. Moisture, access to air, and a temperature in the bacterial “danger zone” are the necessary ingredients for bacteria to flourish.

When we want to preserve food for a longer period of time we automatically remove one or more of these conditions to protect the food. To keep fruit from spoiling for a long time, we dehydrate it. This removes the moisture.

If we want to keep a sandwich edible for a day or two we can put it in a sealable bag in the fridge. This removes exposure to air and pulls it out of the bacteria “danger zone”.

A Big Mac is high in fat, salt, and is already low in moisture. That means it’ll be good for a couple of hours. It will most likely be okay after being left out overnight. Don’t push your luck too much past this range.

If you’re really tempted to eat it past that point, ask yourself, why do you want to eat a 4 day old McDonald’s hamburger? You might need to take a step back and analyze your priorities!

How do the Ingredients Affect a Big Mac?

Close up of Burger ingredients: beef patties, sesame bun, fresh vegetables, pepper, mushrooms over dark wooden table.
Close up of Burger ingredients: beef patties, sesame bun, fresh vegetables, pepper, mushrooms over dark wooden table.

Bread: Bread shouldn’t be refrigerated according to the USDA. This can cause the bread to become staler than it would originally have been. There’s one piece of the Big Mac we don’t have to worry about.

Patty: The meat contains salt and fat. In the restaurant, it will have been cooked to an adequate temperature. Because it’s cooked on a griddle the meat will lose a lot of its moisture during the cooking process.

Sauces: The majority of sauces can be left out at regular room temperature. This applies to ketchup, mustard, and mayo. Those are the usual toppings on a McDonald’s burger.

Cheese: The standard for most cheese is that it will last around 6 hours at room temperature. When it starts to go bad, you’ll notice because of discoloration and it will start to dry out.

Certain kinds of cheese will last longer than others when exposed. American cheese is very processed and pasteurized and so it doesn’t have nearly as many active enzymes as other kinds of cheese that are a little more likely to go bad.

If you’ve read this far, you’re very dedicated to two things: food safety, and eating old food. To you, I say congratulations on being so educated and frugal!

Health Disclaimer

In trying to decide on health decisions consult professionals for a final word of advice. This article is meant to expose you to some USDA standards, and help you gain a base level knowledge of some standard food safety practices.

Many people have been safe and eaten food that was left out overnight, but some people aren’t. Practice caution and use USDA accepted guidelines when making decisions. Enjoy your leftovers, and enjoy some good food with friends!

Anna Silver

Anna Silver is the principal creator of, a website dedicated to new go-to original recipes. Inspired by her grandmother’s love of cooking, Anna has a passion for treating the people in her life to delicious homemade food and loves to share her family recipes with the rest of the world.

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