Are Sandwich Bags Microwave-Safe?
What to know

Are Sandwich Bags Microwave-Safe?

Sandwich bags are disposable food containers. So this naturally means that sandwich bags from Glad and Ziploc aren’t microwave-safe, right? Actually, they are. Keep on reading to find out why!

Sandwich bags and containers can be used to defrost and reheat food and even drinks. They’re plastic so people are rightfully skeptical or concerned about using them for such a purpose, especially since normal food containers typically cannot be microwaved or frozen.

However, the polypropylene and polyethylene plastics of most sandwich bags shouldn’t get exposed to prolonged severe heat because they’re likely to melt if you do.

Are Sandwich Bags Microwave-Safe?

Yeah. As long as the manufacturer, like Ziploc, says it’s microwave-safe and got FDA approval for microwave-safeness then you can use the disposable sandwich bag for microwaving just fine. However, it’s also no. You shouldn’t do microwave cooking or steam on them.

They’re safe for mild heating at 30-second increments but you still have to monitor them in case they melt or warp. If the heat gets too high, like beyond 175°F, this can result in contamination and melted plastic atop your sandwich.

Sandwich Bag
Sandwich Bag

Use Microwave Bags Instead for Cooking

Microwave bags exist in order to allow you to cook things like fish in the microwave with minimal preparation. Ditto microwave steamers or steam containers wherein you can put the water underneath the food tray to steam things like Chinese meat buns.

Sandwich bags should be limited to reheating already prepared food, mostly sandwiches, for no more than 2 minutes and at 30-second increments to lower the risk of the bags catching fire or leaching BPA unto your food.

You can microwave sandwich bags, but using only mild heat and for short periods of time. It should only be used for reheating food and it should be used correctly to avoid the plastic from melting.

Are Ziploc Bags Microwave-Safe?

According to Ziploc, all of their bags are FDA-approved as microwave-safe. A genuine Ziploc sandwich bag can remain stable even when you reheat food inside them care of the microwave. This microwave-safeness extends to their bags for the following:

  • Slider bags
  • Snack bags
  • Freezer bags
  • Sandwich bags
  • Vacuum-seal bags
  • Stand-and-fill bags
  • Easy-open tab bags
  • Double-zipper bags
  • Gallon storage bags
  • 50-quart storage bags

Read more: Can You Microwave Ziploc Bags? Should You Do So Even?

How to Use Sandwich Bags in the Microwave

Although some sandwich bags are microwave-safe, they’re not all-the-way microwave-safe like glassware, ceramic, or even plastic Rubbermaid or Tupperware containers are. You can’t cook with them. You have to limit their microwave radiation exposure or else they could melt.

You should only use them for about 2 minutes or half-minute increments. If they get too hot they could melt, get themselves on fire, or leach off harmful plasticizers that contaminate your food.

Instructions for Microwave-Based Reheating of Food in a Sandwich Bag

  • Cut the Food Up: When reheating food in a microwaveable sandwich bag, cut the food up so that the small pieces get reheated quicker and more evenly. The faster you reheat the food, the less chance of the plastic bag would melt or overheat.
  • Watch out for Fatty or Sugary Foods: Reheating fatty or sugary foods should be done with caution. It’s because molecules for fat and sugar collect more electromagnetic or microwave rays than water molecules, leading to faster reheating and hotter results.
  • High Temperatures: When microwave reheating something like a pork chop or a hot pocket inside a sandwich bag, expect the temperatures to reach much higher than that of a regular glass of water microwaved to boiling, which could melt your sandwich bag.
  • Keep the Bag Unzipped or Open: Don’t allow steam or heat to build up inside a zipped Ziploc bag or Glad sandwich bag. Have an opening to allow the steam to get released instead of collecting inside the bag.
  • Heat Expansion Issues: A zipped Ziploc or a closed Glad sandwich bag can result in pressure, vapor, and heat buildup to grow exponentially until the bag bursts or the food explodes. Don’t turn your meal into a food bomb and leave the bag open as a pressure release.
  • Low or Medium Setting: Don’t microwave the sandwich bag food—like a ham or turkey sandwich—at high. Set it at medium or low power if you can. This will save you overheating and plastic melting risks.
  • Temperature Control: Don’t let the temperature inside the microwave to go beyond 175°F. Also, microwave your food or beverage at 30-second increments for the sake of keeping the temperature at manageable levels.
  • Check for Warping: Check your sandwich bag for melting or warping every 30 seconds. Just because they’re rated as microwave-safe by the FDA doesn’t mean they’re melt-proof or warp-proof. They’re still plastic.
  • Keep the Sauce Separate: Heat the sauce separately in a bowl if possible. Or don’t add the sauce until the last 30-second round of reheating. This is because inside the microwave, liquids heat faster than solids or the non-sauce parts of the meal.
  • The Dangers of Sauces: Adding the sauce at the beginning could raise the temperature of the bag so high that it could melt before the food itself is properly reheated. Only add at the last 30 seconds of reheating or before that if the food gets cooked sooner.
  • Don’t Reheat Crispy Foods: Don’t use sandwich bags to reheat crispy food. The microwave will make the bag humid from the inside, thus making pie crusts and pizzas soggy. It’s better to reheat crispy foods atop a napkin and on ceramic containers.

At the End of the Day

The polypropylene or polyethylene plastics used in sandwich bags have been deemed by the FDA as safe for microwaving but with certain caveats. They can only stay stable for short periods of time under mild heat. Don’t microwave them for too long though.

They can melt, warp, or catch fire at the highest microwave temperatures (comparable to oven temperatures). Use the low power setting to microwave your sandwich bag of food at 30-second increments.

This ensures even cooking without the bag getting compromised or the food getting contaminated. If the bag is damaged or ripped in any way, discard and use a new bag.


  1. Justin Micheal, “Can You Microwave Ziploc Bags And Containers?“, com, May 6, 2021

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