Plastics: What Do Those Numbers Mean?
In addition to PVC (polyvinyl chloride), also avoid using the following plastics with food, as a precaution: #6 PS (polystyrene) and polycarbonate (often indicated by the #7). These plastics have also exhibited the ability to leach questionable chemicals into foods they come into contact with, especially fatty foods and particularly at higher temperatures.
By the numbers
Often found on the bottom of plastic bottles, other containers, and shopping bags, the numbers and letters shown with the chasing-arrows "recycling" symbol mean the following:
- #1 PETE or PET (polyethylene terephthalate): used for most clear beverage bottles.
- #2 HDPE (high density polyethylene): used for "cloudy" milk and water jugs, opaque food bottles.
- #3 PVC or V (polyvinyl chloride): used in some cling wraps (especially commercial brands), some "soft" bottles.
- #4 LDPE (low density polyethylene): used in food storage bags and some "soft" bottles.
- #5 PP (polypropylene): used in rigid containers, including some baby bottles, and some cups and bowls.
- #6 PS (polystyrene): used in foam "clam-shell"-type containers, meat and bakery trays, and in its rigid form, clear take-out containers, some plastic cutlery and cups. Polystyrene may leach styrene into food it comes into contact with. A study in Environmental Health Perspectives concluded that some styrene compounds leaching from food containers are estrogenic (meaning they can disrupt normal hormonal functioning). Styrene is also considered a possible human carcinogen by the World Health Organization’s International Agency for Research on Cancer.
- #7 Other (usually polycarbonate): used in 5-gallon water bottles, some baby bottles, some metal can linings. Polycarbonate can release its primary building block, bisphenol A, another suspected hormone disruptor, into liquids and foods. In 1998, the Japanese government ordered manufacturers there to recall and destroy polycarbonate tableware meant for use by children because it contained excessive amounts of bisphenol A. Other sources of potential bisphenol A exposure include food can linings and dental sealants.
Unfortunately, many plastic products are not labeled with a number or initials. When in doubt, you can call the manufacturer directly. On food products, there is usually a toll-free question/comment number listed.
