Food is closely related with People's Daily lives, so closely contact with food packaging when the choose and buy, I need to pay attention to what aspect? The following knowledge can be reference for need food sack of choose and buy friends:
1, Food packaging bags to choose pay attention to the name of material, there are several kinds of material is we need to be aware of: polyethylene (PE film) is now widely used in food packaging;Transparent polypropylene film (PP film), so it is mainly used for bread, small food packaging;Vinyl chloride film (PVC film) can also be used for vegetables, fruits and other perishable food packaging, but not the packing for greasy food, cannot be used in the microwave heating.
2, When using the microwave food, want to choose the packaging container with a special "microwave".Cold storage, frozen food in the refrigerator should use plastic wrap, and don't use ordinary instead of plastic bags.Cling film special process and raw material has good air permeability and preservation performance, and the ordinary plastic bag use time is a bit long makes food spoilage, decay, and reach the purpose of keeping fresh.
3, Packed in plastic bags cooked food, the direct edible food such as dim sum, it is best not to use colored plastic bags.Because of this many plastic bags are recycled waste plastics processing and become, again can't directly food.
4, PE fresh-keeping film breathable performance is good, have keep on fruits, vegetables, water and the effect of exhaled carbon dioxide, but vegetable oil will rapidly swelling, seepage in it, make it change.Long time contact with vegetable oil will cause the PE film inner content naphthalene exhalation, dissolved in vegetable oil, naphthalene harmful substances into vegetable oil, is extremely harmful for human health.In this way, also can greatly shorten the retention period of foods containing vegetable oil, produced well known or perish.So the PE bag should not be used for packaging Fried foods and foods containing vegetable oil.
5, The other PE plastic film is unfavorable use cooking bags.Because PE plastic film at room temperature can such as acid, alkali, salt solution, then the temperature of the contents once more than 60 degrees, can precipitate, integration.
The last PE plastic film can't do vacuum packing, or packing with spicy and volatile aroma of food.This is because of the characteristics of PE bag: poor leakage, poor resistance capability.