At present, the plastic bags sold on the market are mainly divided into three categories in terms of raw materials: the first category is polyethylene, which is mainly used for packaging ordinary fruits and vegetables; the second category is polyvinylidene chloride, which is mainly used for cooked food. , Ham and other products; the third category is polyvinyl chloride plastic bags. Polyvinyl chloride plastic bags need to be added with additives during production. These additives are easy to migrate out when heated or in contact with oily foods, and remain in the food and cause harm to the human body. Therefore, do not put vegetables and other foods in the plastic bag. Heat it in the microwave, and don’t put the plastic bag in the refrigerator.
In addition, the plastic bag made of any material should be used in accordance with the temperature range specified on the product packaging, and the plastic bag should not be in direct contact with food for a long time. When heating, leave a gap or pierce a few small holes in the plastic bag. In order to avoid explosion, and prevent high temperature water vapor from falling on the food from the plastic bag.
Milk in a flat bag is safe to drink: The flat bag used to pack milk is not a layer of film. In order to maintain air tightness, general plastic bags are made of multiple layers of film, and the inner layer is polyethylene. It will not be a problem to drink after warming.
Colored plastic bags do not pack imported food: At present, many plastic bags used by vendors selling vegetables and fruits on the market are partially transparent and white, but also red, black, and even yellow, green, and blue. Plastic bags are used to pack cooked foods and snacks for direct consumption. It is best not to use colored plastic bags. There are two reasons: First, the pigments used for dyeing plastic bags have strong permeability and volatility, and will easily ooze out when exposed to oil and heat; if it is an organic dye, it will also contain aromatic hydrocarbons. Secondly, many colored plastic bags are made of recycled plastics. Because recycled plastics contain more impurities, manufacturers have to add pigments to cover them.
How to detect the presence of non-toxic plastic bags: non-toxic plastic bags are milky white, translucent, or colorless and transparent, flexible, smooth to the touch, and waxy on the surface; toxic plastic bags are cloudy or light yellow in color, Tacky to the touch.
Water testing method: Put the plastic bag in the water and press it into the bottom of the water. The non-toxic plastic bag has a small specific gravity and can surface. The toxic plastic bag has a large specific gravity and sinks.
Shake detection method: grab one end of the plastic bag with your hand and shake it vigorously. Those with a crisp sound are non-toxic; those with a dull sound are poisonous.
Fire detection method: non-toxic polyethylene plastic bags are flammable, the flame is blue, the upper end is yellow, and it drips like candle tears when burning, has a paraffin smell, and has less smoke; toxic PVC plastic bags are not flammable and leave the fire. It is extinguished, the flame is yellow, the bottom is green, softened and can be drawn, with a pungent odor of hydrochloric acid.
Post time: Dec-17-2021