It is medically controversial as to how harmful storing food and water in plastic containers might be. We do know that when food or water is stored in certain types of plastic, some of the chemicals from the plastic will leach into them. A number of studies have linked the chemicals to cancer, at least in laboratory animals. Others studies indicate that the chemicals may be estrogenic.
Fortunately, not all plastic containers are dangerous, and there are easy ways to tell which are potentially harmful. It turns out that plastic containers are numbered according to their ability to be recycled. This number is found on the bottom of the container in a triangle.
Here are the guidelines you need:
1. Containers with a 1 or 2 on the bottom are the safest. These include clear water containers, as well as most cloudy containers you will find water and milk in. These containers, called PETE and HDPE, are safe for storing food and drink.
2. Containers with a 4 or 5 on the bottom are generally considered safe.
3. Containers with a 3, 6, or 7 on the bottom are the most dangerous. They contain a volatile chemical called BPA which is recognized as harmful.
Finally, it is important to never microwave plastic containers. This increases the likelihood of chemicals from the plastic leaching into the contained food.