Are Ziploc Bags Microwave-Safe?  

They Do Meet US FDA Requirements - But You Need to Understand Proper Use

Ziploc bags are a must-have addition to every kitchen. They make food storage so easy and convenient that it’s hard to go without them (at least for many households). From preserving cooked meals, fresh fruits, vegetables, meats, poultry, etc., in the refrigerator to pack snacks for school or picnics, the bags are a handy packaging solution.

An Overview of Ziploc Brand Bags From the Manufacturer

But how convenient are the bags for reheating or defrosting food? Can you microwave a ziploc bag without risking them melting or chemicals leaching into the food? In other words, are Ziploc bags microwave safe?

The answer is yes- Ziploc bags meet the relevant U.S. Food and Drug Administration (FDA) safety requirements and are therefore safe for defrosting and reheating food in microwaves. So you can microwave Ziploc bags.

While Not All Plastic Bags Are Microwave Safe, Ziploc Bags do Meet FDA Requirements for Microwave Use (It is unknown if the bag in the photo above is microwave safe)

However, when you microwave Ziploc bags, you must observe basic safety precautions to avoid damaging or making them unsafe. Continue reading for the tips and some additional information about the bags and and how to use them safely in a microwave oven.

In the article:

• What Are Ziploc bags?
• What Happens When You Microwave Food in Plastics?
• How to Microwave Food Using Ziploc Bags
• Can You Reuse Ziploc Bags?
• Types and Sizes of Ziploc Bags

What Are Ziploc Bags?

A Ziploc bag is a reusable plastic bag with a press and seal zipper produced by SC Johnson. From Sandwich & Snack bags for packing lunches and snacks to a Freezer bag for long-term food preservation and Storage, Slider, and various specialty bags for ordinary food refrigeration, Ziploc bags come in a wide variety of choices.

Perhaps, the best attribute of a Ziploc bag is that won’t take up much space, not forgetting their superior sealing technology that blocks out air keeping the food fresh. And with different varieties and sizes of bags available - Freezer, Storage, Sandwich & Snack, Slider, etc. - the brand conveniently meets food storage needs.

Besides the storage benefits, the bags are environmentally friendly, which is a plus for the sustainability-conscious consumer. According to the manufacturer, they are both reusable and recyclable and meet the safety requirements for food storage and microwave use.

Here is a quick overview of their features.

• Made from safe plastic - Ziploc bags are a product of polyethylene, a safe and recyclable plastic material with excellent resistance to extreme temperatures.
• Recyclable - If a consumer wants to dispose of used bags, they can rinse them and drop them off (clean and dry) in bins at collection points for recycling.
• FDA-approved - Ziploc bags have met the FDA’s safety requirements for refrigeration/freezing and heating/defrosting.
• BPA-free - Ziploc bags are Bisphenol A (BPA) free. According to studies, (BPA), a chemical used in the production of plastic products, has been shown to interact with estrogen hormone, encouraging the development of endocrine disorders such as infertility (male and female), breast and prostate cancers, among other conditions.
• Dioxin-free - Ziploc bags are also dioxin-free. Dioxin is a pollutant compound that forms as a by-product of burning (when chlorine combines with temperatures above 1,500 degrees F).

What Happens When You Microwave Food in Plastics?

Manufacturing plastics requires adding substances (plasticizers) to increase their flexibility.

Some plastics contain safe additives that can withstand extreme temperatures without contaminating food; others are safe for packing food but only recommended for use under room temperatures, while others are entirely unsuitable for food packaging or storage.

Unsafe plastics contain chemicals that can leach into food. When the plastics are exposed to heat, e.g., microwaving food, the chemicals can leach faster, exposing people to various metabolic and endocrine disorders such as infertility and certain cancers.

For this reason, it’s advisable to refrain from storing or heating food in containers not meant for that purpose, e.g., single-use margarine tubs. Also, one should check manufacturer labels on food containers for instructions on those that are microwave safe and those that are not. Usually, a plastic microwave safe container has a symbol or writing indicating it’s safe.

How to Microwave Using Ziploc Bags

As mentioned earlier, Ziploc bags are microwave-safe, meaning they do not contain harmful additives that may leach into the food during heating. However, it’s essential to observe some basic safety standards when heating or defrosting food using them.

Here are some tips.

1. Follow the usage instructions on the label - Ziploc has a range of bags for use under different temperatures, such as the Freezer bags for freezing food, Zip n’ Steam for steaming, and so forth. As such, reading the instructions on each bag before using it to store, reheat, or defrost food is essential.
2. Place the bag on a microwave-safe dish - As much as the bag is microwave-safe, it’s recommended not to put it directly on the microwave plate when heating or defrosting. If the bag is damaged, the food could spill during heating and damage the microwave; hence it’s safe to place it inside a microwave-safe dish.
3. Vent the bag by opening the zipper about an inch wide - During heating, the steam can build up inside, causing a burst. Always open the zipper about an inch wide to let any pressure that may build up.
4. Do not overheat the food - Overheating food is also discouraged as very high temperatures can damage the bag. Ziploc bags are only suitable for reheating and defrosting; hence it’s safe to stick to low power settings and short heating intervals.
5. Reduce the size of food pieces - Where possible, cutting the food into small pieces can reduce the heating time. Ultimately, this reduces heat damage on the bag and prolongs its life.
6. Handle the bag carefully - The bag gets pretty hot after microwaving food. If not opened or handled with care, it can cause steam burns.

Can You Cook Food in Ziploc Bags?

Ziploc bags are only suitable for reheating and defrosting food. Usually, cooking food requires high temperatures, which can damage the bag. While polyethylene plastic has a melting temperature of 230 degrees Fahrenheit, it may begin to get soft at much lower temperatures.

Even though the bags are free of the harmful chemical BPA, it’s safe to stick to the recommended use and don't expose plastic Ziploc products to high temperature. You definitely don't want to place the bag into boiling water.

Besides, at cooking temperature, the bag can melt into the food, making it unsafe for consumption, or it could burn your hands.

Sous Vide Cooking

Sous vide cooking involves sealing food in a vacuum sealed plastic bag and cooking at low temperatures - between 125 and 195 degrees Fahrenheit. If you choose to participate in sous vide cooking, you'll want to make sure that you're using bags that are designed for this purpose.

The bags should stay intact at temperatures of 195 degrees and above and should be able to be vacuum sealed. Ziploc bags aren't ideal for this purpose.

Sous Vide Cooking Involves Cooking Food Sealed in a Plastic Bag at Medium to High Temperatures

Can You Reuse Ziploc Bags?

Yes, Ziploc bags are not only recyclable, but you can reuse them multiple times before disposing of them. However, to avoid cross-contamination, you should exercise caution with bags used for foods such as raw meat and eggs. If you must reuse the bags, it’s advisable to store similar food products.

Generally, the bags are durable enough to withstand a few washes and reuses. But you should replace it once it gets pricked, torn, or thins out.

Washing Ziploc Bags the Right Way

People have different preferences. Some toss away the bags after a single use, which is also okay because they’re recyclable. However, if you’re one of those who prefer reusing them and saving some extra dollars, here are some cleaning tips.

Washing Using Hands

1. Turn the bags inside out, especially if they had greasy food, for a thorough clean-up.
2. Soak them in the sink with cool or slightly warm water (whichever you prefer). Don’t use hot water to avoid damaging the plastic.
3. Use a sponge and dish soap to clean the bag and rinse under running water.
4. Air dry them before storing food again. Ensuring the bags are dry discourages mold growth, which besides being harmful to your health, can make them smelly. For better drying, you can use plastic bags, a drying rack or improvise one using a stable jar and non-edgy skewers.

Using a Dishwasher

1. Turn the bags inside out and place them in the dishwasher, preferably on the top rack. This way, the water jets can hit the greasy surfaces for a thorough cleaning
2. Anchor the bags with other utensils to keep them from being blown around during cleaning. However, ensure you leave enough space to keep the bags from blocking other dishes.
3. Once they’re clean, pour out any water that may have gathered in the bags and dry them using your dishwasher’s air-dry setting.

Types and Sizes of Ziploc Bags

The type of Ziploc you buy determines how long you can use it. For instance, a Ziploc freezer bag is much thicker than a Ziploc sandwich bag, meaning they can give you more service with repeated use. But that superior feature comes with a higher price, which can be unnecessary when cheaper options are more appropriate.

On the same note, you might require to stock different bag sizes depending on the food portions you want to pack. For instance, smaller bag sizes would be ideal if you need to reheat or defrost small amounts of food. Storing all the food in one big bag would require microwaving it severally, leading to faster damage.

In other words, storing food in the right bag size can also affect its usage (microwaving) frequency. With that in mind, here are the types of Ziploc bags available and their sizes.

Freezer Bag

• Are tough and durable, featuring a sturdy zipper (Grip n’ Seal technology) that locks out freezer burn and keeps the food fresh
• Perfect for freezing poultry, fish, meat, soups, gravies, etc.
• Sizes include: Two Gallon/XL, Gallon/Large, Quart/Medium, and Pint/Small

Storage Bag

• Are durable and feature either a Smart Zip Plus seal or Grip n’ Seal technology, depending on the size
• Ideal for storing poultry, vegetables, fruits, meat, seafood, etc., in the refrigerator
• Sizes include: Two gallon/XL, Gallon/Large, Quart/Medium

Snack & Sandwich Bag

• Used for keeping sandwiches and snacks fresh while on the go, either going to school or picnic, they feature a Grip n’ Seal technology
• Perfect for packing sandwiches, cookies, pizza slices, fruit, carrot sticks, chips, and more
• Features various sizes from XL downwards

Slider Bag

• Flat-based and reliable bags featuring an expandable bottom, Power Shield technology, and Smart Zip seal
• Ideal for storing bulky food and items
• Sizes include: Slider Freezer (Gallon/Large and Quart/Medium) and Slider Storage (Gallon/Large and Quart/Medium)

Specialty bag

• Include a range of bags for specialized use, such as;
• Marinade bags are ideal for storing meats, marinades, and liquids, while Zip n’ Steam bags are primarily for steaming fresh or frozen vegetables, potatoes, etc.
• Zip n’ Steam bags can hold 2-3 servings.

In addition to the ready-to-use bags, Ziploc also features Vacuum Sealer Gallon and Quart Bag Refills, which you can seal using their Vacuum Sealer system. The refills are ideal for storing anything from meat, fish, poultry, fruits, vegetables, pre-portioned meals, etc.