"I try to recycle by re-using, such as the Chinese delivery plastic soup tubs, the plastic tupperware like containers some deli meat comes in, and recently learned I shouldn't microwave them. Is it ok to wash them in a dishwasher repeatedly or will they eventually "go bad" from the pressure and heat?" -- Submitted by Kim C. of New York, NY.
You're certainly doing the right thing by reusing as much as you can, but you are wise to have health concerns about plastic. Hot liquid and scrubbing can cause the plastic surface to degrade, with possible health implications. There are several types of plastic, each the subject of environmental and/or health issues.
Plastics are organized into six general categories. A triangle enclosed number from 1 to 7 can be found on the bottom of many plastic containers. Types 1, 2, 4 and 5 are generally considered to be the safer plastics. Plastic type 3, PVC, contains pthalates, ingredients which make the plastic flexible, but are known to be carcinogenic. Styrene, a suspected endocrine disruptor as well as a possible carcinogen, is a component of type 6, polystyrene. Plastic type 7 contains the hormone disrupter bisphenol A.
Hot foods or liquids can cause plastics to leach or give off bits of component materials. Scrubbing vigorously or scraping the food from a plastic container with a utensil can cause particles to leach. Since plastic is a pliant material, small scrapes and indentations occur easily and can become a breeding ground for bacteria from embedded food or liquid. Much as I hate to see more plastic added to the waste stream, many experts recommend that you err on the side of caution and not reuse these items. Recycle what is allowable under your local regulations. Glass or ceramic containers are a better alternative for food storage, lasting indefinitely and posing no health threats. Glass is readily recyclable, which is not the case with many types of plastic.
Submit your questions about consumer choices and how they affect the environment to cblayer@audubon.org.