Rumors about plastic's detrimental impact on our health have circulated for decades. Though the FDA, CDC, and other official agencies issue periodic reassurances, other experts believe that this miracle of modern alchemy may be lacing our food with chemicals. But you don't have to forgo all your wraps and containers just yet. By learning the ground rules for different types of plastic, you can strike a reasonable balance between convenience and caution.
The FDA keeps close tabs on anything designed for contact with foods -- and it stands by the safety of approved plastic containers, saying they leach negligible amounts of chemicals when used for their express purposes. But what about that yogurt container you used for leftovers and then popped into the microwave for reheating? Since federal standards only address how plastic performs during its "intended use," those of us trying to do the green thing by reusing plastics could be gambling with our health.
Stepping outside the bounds of intended use, we risk heightened exposure to preservatives and other additives. While studies are mixed as to how much of these chemicals we can tolerate, research does confirm at least three things: First, certain types of plastic contain dangerous compounds, including carcinogens and hormone imitators, substances that the body can mistake for estrogen; second, overheating or overusing plastic food containers may cause some of these compounds to "migrate" into food; and third, heat from microwaving or dishwashing and high levels of fat in foods like meat and cheese can expedite this migration.
In the case of polycarbonate, polystyrene, and polyvinyl chloride (plastics often used to make certain cling wrap, takeout, and durable food storage containers), even low-level migration of their chemicals may damage hormone and gene function over time. Studies have yet to prove that concentrations found in food pose a threat to humans, but the basic building blocks of these plastics include known human carcinogens and substances harmful to the reproductive system. Other plastics, such as polyethelenes (used to make some cling wraps and containers as well as zippered bags), contain fewer additives and less toxic ingredients. Optimal safety requires that you abide by manufacturer instructions and, in some cases, take a few additional precautions to minimize your exposure. With a little food-storage know-how, you can easily spot the best -- and the safest-plastic for the job.
polypropylene (PP, #5)
This plastic has a relatively high melting point, so it's usually safe for warm or cold foods. While many of these containers pass microwave-safety tests, they rarely undergo tests for prolonged use and may break down faster than durables. To limit risk of exposure to the preservative BHT, reuse these containers only as long as recommended by the manufacturer. If you can't find recommendations on the product packaging or on the company's Web site, use them no more than five or six times.
high-density polyethylene (HDPE, #2) or polypropylene (PP, #5)
Designed to store food at cold temperatures for a limited time, these containers will likely melt if subjected to heat, increasing your risk of exposure to chemical additives -- so reuse them for cold foods only. Be sure to recycle them when you see signs of wear, such as discoloration, warping, or scratches.
high-density polyethylene (HDPE, #2) or low-density polyethylene (LDPE, #4)
While both types of polyethylene may contain chemical antioxidants to prevent discoloration, they do not appear to cause health problems and are free of plasticizers -- chemicals often added to plastic for flexibility that some animal studies have linked to hormone dysfunction. To minimize exposure to preservatives, avoid using these bags with high-fat foods, which absorb additives more readily.
polyvinyl chloride (PVC or V, #3) or low-density polyethylene (LDPE, #4)
Choose wraps made from LDPE, such as those from Glad or Saran, since PVC contains the known carcinogen vinyl chloride. If you can't find "LDPE" or "#4" (in the chasing-arrows symbol on the box), don't buy it until you've checked with the company online or over the phone. If you buy plastic-wrapped meat or cheese, trim areas exposed to wrapping (since it's often PVC) and store the remainder in glass or ceramic. For freezing, try tempered glass; parchment paper works for shorter periods. In the microwave, use ceramic or glass covers; wraps can melt and release chemicals upon contact with hot foods and liquids.
low-density polyethylene (LDPE, #4), polypropylene (PP, #5), or polycarbonate (PC, #7)
Choose containers marked with #4 or #5; #7 PC can leach low levels of an estrogen imitator. Note that #7 is a catch-all "other" category that includes combinations of safer types, but because you can't discern between these and the #7s made with PC, avoid the category entirely. Many durables are microwave- and dishwasher-safe, but always check labels. Avoid using them to heat sugary foods, like syrup or sweetened tomato sauce, which reach very high temperatures and are more likely to melt plastic.
polypropylene (PP, #5) or polystyrene (PS, #6)
Polypropylene doesn't appear to leach chemicals, but since few takeout containers undergo testing to ensure safety beyond one-time usage, don't keep them for storage. Polystyrene, most recognizable as Styrofoam, can also assume a hard, clear form. Both forms are made with benzene and could leach styrene, a possible human carcinogen and hormone disrupter; they also can't be recycled in most communities. If you have food delivered in any of these plastics, store leftovers in another container. Also, don't reheat your food in them -- even if your takeout shows up cold -- unless you see a "microwave safe" label on the bottom.
high-density polyethylene (HDPE, #2) or low-density polyethylene (LDPE, #4)
These plastics have not been found to leach harmful chemicals, but save them for cold, low-fat foods. Both types of plastic melt fairly easily in this form, and fatty foods are more likely to absorb antioxidant preservatives.
From manufacture to disposal, plastics pollute air and water, consume massive amounts of fossil fuels, and take up landfill space. Here's how to reduce your impact.
1. Know your numbers. The number and chasing-arrows symbol on plastic containers indicates type of plastic -- not whether it can be recycled. Visit earth911.org or call 1-800-CLEANUP to find out which numbers your community recycles.
2. Pack your bags. The 100 billion plastic bags that Americans use every year require more than 21,000 barrels of oil daily to produce. Plastic recycling is expensive and energy intensive, so keep a stash of cloth or once-used grocery bags on hand to carry purchases.
Here is a simple way to make grocery bags sturdy enough for long term use:
Collapse the bottom of the paper bag.
Slide the paper bag into a plastic bag. Cut off the top portion of the paper bag in a gentle arc to create a wider opening for easier use.
Fit the bottom corners of the paper bag into the plastic bag to create a secure and sturdy foundation.
For easy packing and travel, simply fold your homemade bags up, tucking in the plastic and handles, and fold the bags in half. Multiple bags held together with rubber bands will fit neatly into the compartment in your car door or in your trunk.
3. BYORB. Bring your own reusable bottle. Check out Klean Canteen's lightweight stainless steel bottles at rei.com. When you do purchase a drink on the go, choose glass over plastic since it recycles more efficiently.
4. Skip the packaging. When you buy produce, think twice before grabbing a bag. Oranges, onions, and many other items don't need the extra protection. For prepackaged goods, buy in bulk to minimize waste.
5. Get involved. The Center for Health, Environment, and Justice recently launched a campaign to encourage companies to phase out PVC use in favor of less harmful materials. Microsoft, Victoria's Secret, and Wal-Mart are already on board. Help build momentum for change by visiting besafenet.com/pvc.
By Josie Garthwaite
Photograph by Peter LaMastro
Styling by Allison Canter
© 2013 Martha Stewart Living Omnimedia. All rights reserved.