Understanding the Resin Code: What is Number 5 Plastic?
When you look at the bottom of a plastic container, you'll often see a triangular recycling symbol with a number inside. This number is the Resin Identification Code (RIC), and for number 5 plastic, it signifies the material is Polypropylene, or PP. Polypropylene is a versatile thermoplastic polymer that is known for its durability, flexibility, and excellent resistance to heat and chemicals. Unlike some other plastics, it is naturally opaque and lightweight. Its properties make it a popular choice for a wide variety of consumer products, from car parts to textiles.
Where You Find Number 5 Plastic in Your Home
Polypropylene is a staple in many households, primarily because of its food-grade status and heat resistance. It is often used for products that need to withstand high temperatures or repeated use. You will typically find it in:
- Yogurt, margarine, and sour cream tubs
- Bottle caps and lids for various containers
- Syrup and medicine bottles
- Some reusable food storage containers like Tupperware
- Microwave-safe trays for prepackaged meals
- Drinking straws
- Packaging for certain snack foods
Is Number 5 Plastic Food Safe? The Verdict
In short, yes, number 5 plastic is generally considered safe for food contact by regulatory bodies such as the U.S. Food and Drug Administration (FDA). This safety is attributed to several key characteristics:
- High Heat Tolerance: PP has a high melting point, typically between 320°F and 331°F (160-166°C), and can withstand normal microwave heating and dishwasher cycles without breaking down.
- Chemical Resistance: It is non-reactive with most foods and liquids, which means it is less likely to leach harmful chemicals into your food, even when heated.
- BPA-Free: A major advantage of polypropylene is that it does not contain Bisphenol A (BPA), a chemical found in some other plastics that has raised health concerns.
The 'Generally Safe' Caveat: What to Know
While considered safe, it's crucial to understand the nuances. Some older research has pointed to potential issues with certain manufacturing additives or degradation over time. The most prudent approach is to follow best practices for food storage and heating, which includes replacing any container that shows signs of wear such as cracks, scratches, or discoloration. If you are concerned about any potential for minor chemical leaching, especially with fatty foods or high heat, transferring food to a glass or ceramic dish for heating is the safest option.
Comparison of Plastic Types for Food Safety
To put #5 plastic's safety into context, it is helpful to compare it to other common plastic types. The following table provides a quick overview based on resin codes.
| Resin Code | Plastic Type | Food-Safe for Reusable Use? | Common Food Uses | Microwave Safe? |
|---|---|---|---|---|
| 1 | PET (Polyethylene Terephthalate) | No (Single Use) | Water bottles, soda bottles, salad dressing | No |
| 2 | HDPE (High-Density Polyethylene) | Yes | Milk jugs, juice bottles, butter tubs | Generally |
| 3 | PVC (Polyvinyl Chloride) | No | Biscuit trays, cling wrap | No |
| 4 | LDPE (Low-Density Polyethylene) | Yes | Bread bags, squeeze bottles, some wraps | No |
| 5 | PP (Polypropylene) | Yes | Yogurt tubs, margarine tubs, reusable containers | Yes |
| 6 | PS (Polystyrene) | No | Styrofoam cups, meat trays, egg cartons | No |
| 7 | Other / Mixed Plastics | No (Avoid) | Some baby bottles, 5-gallon water jugs | Often No |
The Lowdown on Recycling Number 5 Plastic
While polypropylene is widely used and generally considered safe, its recyclability is a more complex issue. Polypropylene is technically recyclable, and recycled PP can be used to make new products like car battery cases, brooms, and storage bins. However, several factors make it less straightforward to recycle than plastics #1 or #2:
- Varied Acceptance: Not all local municipal recycling programs accept #5 plastics. The economics of collecting and processing can be challenging, leading some facilities to not handle it.
- Contamination: Many PP products are found in food packaging, and residue can contaminate recycling streams if not properly cleaned.
- Degradation: Mechanical recycling can degrade the polymer, reducing its quality over successive cycles. Some recyclers mix it with new PP to maintain quality.
Check with your local recycling guidelines to see if #5 plastic is accepted in your area. For products not accepted curbside, programs like Preserve's Gimme 5 (if still active) offered a drop-off option, or check Earth911 for local alternatives.
Conclusion
Number 5 plastic, made of polypropylene (PP), is a safe and reliable choice for food contact, backed by FDA approval and scientific evidence. Its standout qualities, including high heat resistance and being naturally BPA-free, make it superior to many other plastic types for repeated use, including microwaving. While it is technically recyclable, the process is less widespread and more complex than for other plastics, so always check local guidelines. By using #5 plastic responsibly, such as replacing damaged containers and checking for microwave-safe labels, consumers can confidently use this material for their food storage and heating needs while staying informed about its environmental impact.
