Can You Microwave Ziploc Containers?

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Microwaving plastic containers can seem scary. You’ve probably heard the warnings about harmful chemicals leaching into your food when you microwave plastic. So, is it really safe to microwave those handy Ziploc containers? Let’s take a deeper look at the facts.

The Controversy Around Microwaving Plastic

The controversy stems from studies conducted over 30 years ago that suggested two potential issues with microwaving plastic:

  1. Heat could cause plastic to warp and leak chemicals into food.
  2. Chemicals called phthalates and bisphenol A (BPA) used in older plastics could leach into food, especially foods high in fat.

However, a lot has changed in 30 years. Modern food storage plastics are designed to be microwaved without leaching chemicals. Still, some people remain hesitant to microwave plastic of any kind.

Are Ziploc Containers Microwave-Safe?

According to Ziploc, their containers are 100% safe for microwaving. Here are a few key points from Ziploc’s website:

  • Ziploc containers do not contain phthalates or BPA – chemicals of concern in older plastics.
  • They are made from high-quality, microwave-safe plastics that do not warp from heat.
  • Ziploc containers and bags have been rigorously tested and deemed microwave-safe by consumer safety organizations.

Additionally, Ziploc complies with FDA regulations that prohibit any chemicals from migrating into food at levels that could pose a health risk.

Key Microwaving Guidelines

While Ziploc states their containers are safe to microwave, they do recommend a few precautions:

  • Do not microwave plastic containers above 212°F as very high heat could potentially cause warping over time.
  • Vent the lids – do not microwave sealed containers as steam buildup can make them warp or melt.
  • Do not microwave plastic that is stained or damaged.
  • Do not microwave plastic bags or plastic wrap, only rigid containers.

By following these tips, Ziploc says their containers provide safe, convenient microwaving.

Safety Standards for Microwave-Safe Plastics

For a plastic product to be labeled as microwave-safe, it must meet FDA requirements for minimal chemical migration. Specifially:

  • Formaldehyde – Less than 15 parts per billion can migrate into food when heated.
  • Dioxins – Less than 30 parts per trillion allowed.
  • Phthalates – Tiny amounts may migrate but must be far below levels of concern.

These strict safety standards ensure microwave-safe plastics will not pose health risks with normal use.

Here is a comparison of the allowable chemical migration limits for microwave-safe plastic versus other safety standards:

ChemicalMicrowave-Safe LimitEPA Safety Limit
Formaldehyde<15 ppb80 ppb (drinking water)
Dioxins<30 ppt0.7 ppt (drinking water)

As you can see, the amount of chemicals that could potentially migrate into food during microwaving is minute and well below other safety limits set by the EPA for food and drinking water.

Are There Any Risks to Microwaving Plastic?

With microwave-safe plastic like Ziploc containers, the risks are very low based on current evidence and safety standards.

A few general precautions include:

  • Don’t microwave anything in cracked or damaged plastic.
  • Don’t microwave plastic bags or plastic wrap – only rigid containers. The thinner plastic can more easily warp or melt.
  • Avoid microwaving fatty or oily foods in plastic, as these can theoretically absorb more chemicals.
  • Don’t microwave plastic above 212°F. This keeps the heat low enough to limit any potential warping.

By following basic guidelines, microwave-safe plastic offers a convenient way to quickly heat up leftovers, prep meals, and more. Any potential risks are minimized.

Microwaving Dos and Don’ts

To safely microwave in plastic containers, keep these dos and don’ts in mind:


  • Do choose plastic containers labeled “microwave-safe”
  • Do follow any instructions provided on container packaging
  • Do vent lids before microwaving to allow steam to escape
  • Do space food out evenly to prevent uneven hot spots
  • Do microwave food in shorter bursts and stir periodically


  • Don’t microwave plastic bags, plastic wrap, or styrofoam
  • Don’t microwave stained, damaged, or cracked plastic
  • Don’t microwave plastic with metallic paints or trims
  • Don’t microwave melamine plastic labeled “not for food use”
  • Don’t microwave above 212° F – use lower power levels

Following these simple dos and don’ts will ensure you safely use plastic containers in the microwave.

Food Safety Tips for Microwaving in Plastic

In addition to the plastic itself, food safety is also an important consideration when microwaving in plastic:

  • Use plastic containers meant for food prep and storage – Don’t reuse containers not intended for food, like plastic tubs or takeout containers.
  • Avoid reheating in plastic multiple times – Bacteria can build up on plastic over time. Use fresh containers for leftovers.
  • Don’t allow food to touch sides of container – This prevents direct contact with plastic during heating.
  • Wash containers thoroughly before each use – Use hot water and dish soap and dry completely.
  • Inspect for damage before microwaving – Don’t use containers that are cracked, stained or have cloudy looking plastic.

Following food safety best practices reduces any risks when using plastic containers in the microwave.

Microwaving Plastic vs. Glass

While plastic is considered safe these days, some people still prefer to use glass containers in the microwave. Here’s how plastic and glass compare:


  • Specifically designed for microwave use
  • Affordable, lightweight and shatterproof
  • Can warp or melt if overheated
  • Can absorb stains and odors over time


  • More resistant to high temperatures
  • Non-porous surface won’t absorb stains or flavors
  • Heavier and can shatter if dropped
  • Not always microwave-safe – check labels

For reheating leftovers, both materials are safe options when used properly. Glass is best for foods that need high heat like casseroles. Plastic works well for briefly heating foods like slices of pizza.

The Bottom Line

Based on all current research and safety testing, Ziploc containers are considered 100% safe for microwaving. Other microwave-safe plastic containers made from high-quality plastics and labeled “microwave-safe” are also considered safe choices.

Plastic products have come a long way over the past few decades. Reputable brands like Ziploc use innovative materials and rigorous safety testing to ensure their products can withstand microwave use without posing risks. By following the basic safety tips provided, you can confidently microwave foods in Ziploc containers and other microwave-safe plastic ware worry-free.

So next time you need to quickly reheat leftovers or prepare a meal, feel free to reach for those handy Ziploc containers! Just be sure to vent the lid and avoid overheating them. Then enjoy your conveniently microwaved meal knowing you can feel safe using these innovative products.

By Rosie Elliott

I’m Rosie. I’m a professional chef with experience in Western, Mediterranean, and Italian cuisine. I’ve been cooking for over 15 years, and I have two daughters that keep me busy!

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