Microwaving plastic containers can seem confusing – with so many different types of plastics out there, how do you know which ones are safe to use? If you’ve ever noticed those numbers printed on the bottom of plastic containers, you’ve probably wondered what they mean. One common question is: is number 5 plastic microwave safe?
The short answer is yes – number 5 plastic, also known as polypropylene (PP), is generally considered safe for microwave use. Polypropylene has high heat resistance and won’t melt or leach chemicals into your food when heated.
What Do The Numbers On Plastic Mean?
The numbering system used on plastics is known as the resin identification coding system. It was created by the Society of the Plastics Industry to help consumers identify and properly recycle different types of plastic.
Here’s a quick rundown of what each plastic number stands for:
- 1 – PETE (Polyethylene Terephthalate)
- 2 – HDPE (High Density Polyethylene)
- 3 – PVC (Polyvinyl Chloride)
- 4 – LDPE (Low Density Polyethylene)
- 5 – PP (Polypropylene)
- 6 – PS (Polystyrene)
- 7 – Other/Miscellaneous
Generally, you want to avoid putting plastics labeled 3, 6, and 7 in the microwave, as these types of plastics can melt and leach chemicals when heated. Number 5 PP plastic, on the other hand, has a high melting point which makes it more stable and safer for microwave use.
Why Is Number 5 PP Plastic Ideal For Microwaves?
Polypropylene, or number 5 plastic, is a thermoplastic polymer that can withstand temperatures up to 230°F without deforming. Here are some of the properties that make PP an ideal choice for microwave-safe plasticware:
- Heat resistance – PP plastic retains its shape even when exposed to boiling water. It won’t warp or melt in the microwave.
- Microwave transparency – PP allows microwaves to pass through evenly and heat food contents. Other plastics can block or absorb microwaves.
- Sturdy – Items made from PP plastic are durable and won’t crack or scratch easily. Damaged plastics are more likely to leach chemicals.
- Non-leaching – PP is chemically stable and does not contain plasticizers. Chemicals like BPA and phthalates won’t leach out.
- Reusable – You can keep using PP plastic containers without degradation. Don’t reuse other plastics after microwaving.
Overall, number 5 polypropylene ticks all the boxes for safe, reusable microwaveable plasticware.
How To Tell If A Plastic Container Is Microwave-Safe
The plastic resin code is a good starting point to tell if a container is microwave-safe, but here are some other tips:
- Check for microwave-safe symbol – Look for the microwave-safe symbol or words indicating it’s safe for microwave use.
- Avoid old, damaged plastics – Don’t use old, cracked or scratched plastic in the microwave. This can allow chemicals to leach out.
- No foam containers – Foam products like Styrofoam are never microwave safe.
- Don’t reuse some plastics – Single-use plastics like deli containers are not meant for repeated microwave use.
- Follow container guidelines – Check the package or manufacturer’s instructions to verify microwave safety.
- Use BPA-free plastics – Look for a BPA-free symbol if microwave safety is unknown.
Following these simple guidelines will help you determine if a plastic container is truly microwave-safe. When in doubt, switch to glass or ceramic microwave-safe dishware instead.
Safely Microwaving Number 5 Plastic Containers
While polypropylene plastic is microwave-safe, you’ll want to take some additional precautions when heating food in PP containers:
- Use lower power settings and shorter cooking times. Avoid high temperatures.
- Don’t microwave empty containers. Food absorbs some of the heat.
- Allow food to cool before removing from the container. Hot food can still leach chemicals.
- Transfer heated food to another non-plastic container. Don’t store or reheat food in plastic.
- Discard any warped or damaged containers. Don’t reuse questionable plastics.
- Never microwave plastic with metallic paints, trims or glues.
Following the manufacturer’s instructions and avoiding overheating number 5 plastic containers will ensure safe, chemical-free microwave cooking.
What If Plastic Melts in The Microwave?
If you ever notice plastic containers or wrap melting in the microwave, stop the microwave immediately. Melting plastic is a sign that the plastic is not microwave-safe and can release toxic chemicals into your food. Even if the container is labeled microwave-safe, it’s possible for plastics to warp, melt, or scald when heated too long or at too high of a temperature.
Plastic that has melted in the microwave should not be used again. The bonding of the plastic breaks down when melted, allowing harmful phthalates, dioxins or other plasticizers to leach out of the container and into food. Consuming food that has touched melted plastic can cause hormonal issues, reproductive problems, cancer, and other long-term health effects.
You’ll want to discard any food that has come into contact with melted plastic, even if it looks untouched. It’s not worth the health risks. Going forward, always double check that plastics are microwave-safe and avoid putting them in for extended periods at high heats. Switch to glass or ceramic containers if you have any doubts about microwave safety.
The Takeaway On Number 5 Plastic
When used properly, polypropylene or number 5 plastic containers are generally considered safe for microwave use. PP plastic is resistant to heat, microwave-transparent, and non-leaching. Take care to identify microwave-safe plastics, follow usage guidelines, and avoid overheating.
With the proper precautions, number 5 plastic is a good option for reheating leftovers and cooking convenience foods. But when in doubt, choose glass or ceramic microwave-safe dishware for guaranteed safe use. Checking plastic numbers, symbols, and labels allow you to make informed choices when microwaving plastic.