We're reader-supported. If you buy through our links, we may earn a commission at no cost to you.

Accidentally Left Frozen Fries Out Overnight?

Whoops! You left the fries out overnight. Do you throw them out or do you pop them back in the freezer?

When unpacking groceries or preparing food for the household, it’s often tempting to get distracted by the things life throws our way. In doing so, we can forget simple but important steps to ensure the safety of the food that we and the family members at our table eat.

If you left a bag of frozen fries out on the counter, no matter if they were opened or not, and you forgot to put them back in the freezer—where they belong—should you throw them out, or are they still safe for you to cook and eat?

Frozen fries are a perishable food. As such, they shouldn’t be kept at room temperature for more than 1-2 hours. Otherwise, harmful bacteria may form in the package and render the fries unsafe to eat.

According to the USDA’s Food Safety and Inspection Service, leaving perishable food out too long at room temperature can cause harmful bacteria to grow to dangerous levels on its surface, and thus cause food-borne illness.

This includes breeds of pathogenic bacteria (a “pathogen” meaning any organism that can cause disease) that we’ve all read and heard about, including but not limited to Staphylococcus aureus, Salmonella Enteritidis, Escherichia coli O157:H7, and Campylobacter.

Bacteria require five conditions to thrive: a source of protein, sufficient moisture, favorable temperature, moderate acidity, and enough time. Frozen fries, with a good amount of plant protein, plenty of moisture, and their mild acidity, are a good breeding ground for bacteria when left out.

The Centers for Disease Control and Prevention (CDC) estimates that 48 million Americans contract food-borne illnesses each year. Of them, 128,000 are hospitalized and 3,000 die.

Simply put, if you left frozen fries to sit out for too long, no matter if you opened the package or not, play it safe and throw them away. It’s better to give up fries for dinner than to end up with a stomachache or, worse, food poisoning.

Will Cooking the Fries Make Them Safe to Eat Again?

Despite lore to the contrary, cooking fries—on the stove, in the oven, air fryer, or microwave—that have been left to sit out for too long won’t make them any more safe to eat.

Although cooking and reheating does kill most bacteria, it doesn’t remove or inactivate the toxins that these bacteria left behind in your food. In many cases, it is those toxins that give you food poisoning.

Some bacteria can form endospores, an extremely resistant inner layer that protects them from adverse conditions such as high heat or dehydration. As soon as the conditions have normalized, the bacteria reactivate.

What If They Don’t Smell or Taste Bad?

The bacteria that can make your food spoil are not the same as the bacteria that can give you food poisoning. In other words, the fries in the package may look, smell, and taste perfectly safe to eat, even if they really aren’t.

Spoilage bacteria give food a mushy feel, off odor, and repulsive flavor. Pathogenic bacteria don’t, so it’s virtually impossible for you to tell if the fries are safe just by looking at them, smelling them, or giving them a taste test.

When it comes to food storage, temperature and time are the two factors that you need to care about. The hotter it is and the longer you leave fries out, sealed or opened, raw or cooked, the less they will keep.

In summer, especially when the outside temperature is 90°F (32°C) and above, don’t leave fries out for longer than 1 hour. In fall, winter, and spring, you can safely leave food out for up to 2 hours.

Warm, Refrigerate, Freeze, or Discard

Whenever you’re dealing with a perishable food item, you have four options to choose from: warm, refrigerate, freeze, or discard.

If you’re hosting a party or cookout, you can keep perishable food items, including fries, safe to eat for hours on end by keeping them at a temperature at or above 140°F (60°C).

This can be done in the oven, but a more convenient option that gives your guests access to the food is a disposable aluminum chafer or stainless steel chafer

Should you choose to go this route, emulating the catering professionals, you will also need chafing dish fuel cans, each capable of keeping your food warm for 2 hours.

If you just want to keep food safe for you and the family to eat, refrigerate or freeze uncooked foods shortly after bringing them back home from the grocery store or farmer’s market.

Chill cooked foods to room temperature, wrap them in plastic or transfer them to food storage containers, and put them in the fridge for short-term or in the freezer for long-term storage.

The shelf life of refrigerated foods will vary. However, all frozen food items remain safe to eat indefinitely, as freezer temperature puts bacterial activity on halt. That said, frozen food eventually dries out and loses its best texture, aroma, and flavor, so don’t take too long to eat it up.

As a general guide, uncooked fries keep their best quality for up to 12 months in your freezer. Refrigerated, cooked fries stay good for 4 to 5 days.

Know your author

Written by

Jim is the former editor of Home Cook World. He is a career food writer who's been cooking and baking at home ever since he could see over the counter and put a chair by the stove.