Glass and Plastic
We are very used to two materials when it comes to packaging of food: Glass and Plastic. Both are extraordinary materials. Glass is already known to mankind since 7000 BC, plastic since 1940.
The fact that a lot of food is packed in plastic nowadays means that packaging in plastic seems to have some advantages over glass.
The most important advantages are that plastic is cheap and light. That plastic doesn’t break and is rather flexible is another important factor. That many plastics are transparent is probably also one of the main reasons that it was considered as an alternative to glass.
Walk into a supermarket and see a whole range of plastic food packagings. At the soft drink section you see a lot 無塵工作間 of plastic bottles and many pastes, sauces and all kind of chips and other dried foods are packed in plastic. Besides you see many containers to keep food in, like boxes for in the freezer and boxes to store left overs.
Glass is also used much as a packaging material for food. Bottles for drinks, for conserved vegetables and fruits, tomato ketchup and other sauces, etc.
One thing which is noticeable is that glass seems to be the preferred material for long-lasting products and products which are easily to decay.
Glass vs. Plastic
That glass is used for long storage of foods is logic. Glass is absolutely impermeable to gases and hence blocks the content from the oxygen in the air. Oxygen has the property that it oxidizes food and that means aging of the food. Some bacteria and fungus also need oxygen and the use of glass makes it impossible for them to grow. Glass is easy to sterilize.
Glass is also totally tasteless and it doesn’t affect the taste or smell of any food packed in it. Plastic food containers do have a light or heavy smell.
What you can not see or feel are the additives which leach out of the plastic into your food. These additives range from anti-oxidants, anti-static agents, plastifiers, flame retardants, filling materials, colorants and light stabilizers, etc. Sometimes the plastic what you see is about fifty percent of the base plastic material and fifty percent of these additives.
The plastic packaging industry is of course aware of the additives and by government rules they have to diminish this leaching out of additives into the food. So they choose for additives with less mobility, special surface treatments to avoid leaching, additives which are tasteless or non-toxic where possible.
Whether non-toxic or not, these additives are leached into the food and you don’t see it, so most of the time you don’t know what is entering your body. The bad part is that in our modern society the government makes rules containing maximum allowable concentrations. As long as the leaching out of additives is below these values than they are accepted and may be used. The scary part of this is that by using these plastic containers, very low quantities of these additives are part of your food.
Safe according to the laws means not that there might not be any health effects. Yes-or-no discussions about some additives are going on for long times and sometimes it seems to be that some long-term effects were not known at the moments that the allowable concentrations were chosen.
Sure, some plastics, like HDPE and PET, have less additives than others but common additives like phthalates and bisphenol A, have been analyzed in the human population all over the world.