Common plastic food bags are made from polyethylene film, the film toxic, it can be used to hold food. There is a thin film made of polyvinyl chloride, PVC itself is also non-toxic, but according to the film's use of additives is often joined by harmful substances, have some toxicity. This type of film and the films of plastic bags should not be used for holding food. To identify PVC plastic bags and polyethylene plastic bag, can be identified by following simple.

Polyethylene film (non-toxic)

Thin Milky, translucent (a few stacked to observe especially), which feels more lubrication, seems on the surface is coated with a wax layer, jitter, sound brittle, fire flammable, yellow flames, burning mucus drip and smell the burning candles.

PVC film (commonly toxic)

If not pigment, transparent surface in some sticky to the touch, shake, voice low, fire resistant and burning, fire that was put out, the flame is green.