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Is It Safe to Heat Food in Ziploc Bags? | What to Know

Plastic containers and packaging play an important role in the kitchen. Plastic containers help to protect food from spoiling, preserve its freshness, and reduce waste. Ziploc plastic bags and containers are very popular for their versatile use in the kitchen, but there’s a lot of confusion going around on whether they are safe for heating food.

It is perfectly safe to heat food in a Ziploc bag. Ziploc bags and containers are specially manufactured for the safe heating of food in the microwave or oven. They meet the safety and quality requirements of the FDA (Food and Drug Administration) for toxicity, chemicals, and melting properties.

For frequent reheating in the microwave, here are some Ziplocs specifically designed for the microwave, found on Amazon.

While it is safe to heat food in Ziploc bags, there are certain risks involved if you’re not doing it the right way or using the correct equipment or bags. In the rest of this article, we’ll discuss in detail how to ensure food safety when heating food in Ziploc bags.

Is Heating Food in a Plastic Bag Safe?

Food in Ziploc Bag in Microwave

Cooking or heating food in a plastic bag comes with its risks. Chemicals from the container may leach into your food, the plastic can melt, and you could suffer bodily burns if the bag is not used properly. The only plastic bags recommended for heating or boiling food are those approved by the FDA and labeled as such.

Before plastic manufacturers can get this designation from the FDA, their containers must have been tested and evaluated for melting times and temperatures, toxic chemicals, and other behaviors under heat and acidic conditions.

One of the chemicals that has caused a lot of safety concerns is Bisphenol A (BPA). It is a chemical used in making certain types of plastics, such as water bottles, plastic plates, and cling wraps. BPA has an estrogen-like structure. It can bind with estrogen hormones and affect bodily functions such as growth, reproduction, energy levels, and cell repair.

Plastic bags made out of a type of plastic known as polycarbonate release BPAs when heated to a high temperature. This chemical is dangerous and is mostly found in plastic plates, take-out containers, and cling wraps. Also, plastic bags made out of Polyvinyl Chloride (PVC) should not be used to heat food as they release dioxin when heated to a certain temperature.

The safest plastic bags to heat food in are those made with high and low-density polyethylene. These types of plastic are denser than other plastics; hence they are safe even under high heat. Ziploc bags are completely safe for heating food as they are made out of polyethylene without any additives and are both BPA-free and 100% dioxin-free.

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Which Ziploc Bags are Safe for Heating Food?

When choosing a Ziploc bag or any other zipper-lock bag to heat your food in, it is important to read its package label. By following the label directions on your Ziploc bag, you’re ensuring the safety of yourself and your food.

In general, only Ziploc storage bags may be used for heating or reheating food in the microwave. You can also use Ziploc freezer bags for defrosting frozen food without any concerns. For steam cooking, Ziploc zip ‘n steam bags are specifically designed for this purpose. Again, it is important to check the label of the Ziploc bag before using it.

It is not recommended to use Ziploc produce bags, bread bags, and sandwich and bread bags for heating food. Although they do not contain BPA, these bags are too thin and can melt and release chemicals or ink into your food.

How Hot Can Ziploc Bags Get?

I mentioned earlier that Ziploc bags are made out of polyethylene. Polyethylene plastic typically softens when heated at about 195°F or 90°C. This softening point means that the plastic will start melting at the boiling point of water, which is about 212°F or 100°C.

To avoid any issues whatsoever, always heat your food below the bag’s softening temperature. Going over this temperature can cause the bag to fail and ruin your food with plastic, ink, and all sorts of chemicals.

If you’re heating food in water temperatures close to the softening temperature, I recommend combining two Ziploc bags because heat can open up the bag at the seams and allow water into the food.

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Reheating Food in Ziploc Bags


Ziploc bags are BPA and dioxin free, and you can safely reheat your food in them. Most of these bags are labeled “microwave-safe” and have been approved by the FDA. Also, defrosting frozen food in a Ziploc freezer bag is perfectly safe, and no harmful chemicals will be released into your food.

However, steam can build up inside the bag when it is being heated, which can cause it to rupture and melt. To prevent steam and pressure buildup in the bag, always open a corner of the zip one inch to allow the steam to escape. If you’ll be heating the bag in a microwave, ensure it is placed on a microwave-safe dish and avoid going above the softening temperature of the bag.

Also, if you’re reheating foods that have high fat or sugar content such as bacon, cheese, and pastries, you will need to be very careful as they can heat up very quickly to high temperatures, sometimes exceeding the bag’s softening temperature. To avoid the growth of harmful bacteria, heat your food at or above 140°F or 60°C.

More Safe Ziploc Heating Tips

Ziploc bags are one of the greatest innovations in the world of food storage. They are convenient and robust and won’t melt, burn, or make you sick if you use them correctly. Here are some extra tips you could use when reheating those leftovers in your kitchen.

When heating food in a Ziploc bag, always handle it with care, as the bag and its content may become very hot. Be sure to read the instructions on the package and check for the specific heating requirements of the bag.

Also, to make your heating easier and reduce the heating time, you may cut the food into smaller pieces. Reduced heating time also helps to keep the bag from warping, thereby prolonging its life. If you can’t find the label “microwave-safe” on the bag, check for a microwave symbol or image with squiggly lines on it.

Final Thoughts

Ziploc bags are safe for boiling and reheating food. They are made out of polyethylene and do not contain dangerous chemicals such as Bisphenol A (BPA) or Dioxin. Ziploc bags are also FDA-approved, so you can have peace of mind when using them.

However, using Ziploc bags has its risks and can cause food or bodily damage if not used correctly. Here are the most important things to keep in mind when heating food in Ziploc bags:

  • Never use plastic zipper-lock bags made with Polyvinyl Chloride (PVC) or polycarbonate plastic for heating food.
  • Always check the label on the bag for the specific maximum and minimum temperatures it can handle.
  • Only use Ziploc storage bags for reheating leftover food and Ziploc freezer bags for defrosting frozen foods.
  • Avoid using Ziploc produce bags, bread bags, and sandwich and bread bags for heating food.
  • As a general rule, never heat food above the softening point of polypropylene, which is 195°F or 90°C.
  • Always leave a small opening at the corner of the zipper to allow steam to escape from the bag.
  • Be careful when handling the bag and its content. Foods high in fat and sugar can heat up very quickly to high temperatures.