Good information for storing in plastic.

Safest plastics for food and beverages
By Lori Bongiorno Posted Mon Nov 3, 2008 10:28pm PST

Some plastics are safer to eat and drink from than others. Here's a quick guide to help you make informed choices. If you want to dig deeper, take a look at the Institute for Agriculture and Trade Policy's Smart Plastics Guide (PDF).
It's worth avoiding the following plastics when you can. You can identify a plastic by looking at the recycling code number that appears inside a triangle at the bottom of many containers.

Polyvinyl chloride (PVC) can leach phthalates, known male reproductive toxicants. It can be identified by code 3. One way to avoid it in the kitchen is by choosing plastic wrap made from polyethylene rather than PVC. If a box is not labeled, find a brand that is or call the manufacturer.

Polystyrene is used in Styrofoam products. It may leach styrene (a neurotoxin) when it comes into contact with hot, acidic, or fatty foods. It's marked with recycling code 6.

Polycarbonate can leach bisphenol-A (BPA), an endocrine disruptor associated with a long list of health concerns. Baby bottles, "sippy" cups, 5-gallon water jugs, and reusable beverage bottles are typically made out of this plastic. Products may be marked with recycling code 7 (also includes any plastic that doesn't fit into the 1 to 6 recycling code categories) and/or the letters "PC."
In response to the widespread concerns about BPA, baby bottles and other items made from alternative materials are springing up. Experts say stainless steel is your best bet for reusable water bottles right now. ThinkSport and Klean Kanteen are two widely available brands.
The following plastics are considered safest for food storage. Glass and stainless steel are also good options.

Polyethylene terephthalate ethylene (PETE), code 1.

High-density polyethylene (HDPE), code 2.

Low-density polyethylene (LDPE), code 4.

Polypropylene (PP), code 5.

Here are some tips for using all plastics safely:
Don't microwave food plastic containers. Chemicals are more likely to leach out when plastic is heated. "Microwaveable plastic" doesn't guarantee that chemicals won't leach. Cover foods in the microwave with wax paper or a plate. If you do use plastic wrap, then make sure it doesn't touch the food.
Avoid putting hot foods in plastic containers. Let leftovers cool off before storing them in plastic.Take good care of plastics by not washing them with harsh chemicals, and dispose of scratched and worn containers. Research has shown that older, scratched items will leach more, says Kathleen Schuler at the Institute for Agricultural and Trade Policy. (Don't put them in the dishwasher if you want to be completely risk-averse, she suggests.)