Packaging: protection or poison?


Researchers from the Bely Institute of the Mechanics of Metal-Polymeric Systems NAS of Belarus decided to test the quality of well-known packaging materials, polymer films.

It is clear that films are necessary, to transport, package, protect products from harmful microorganisms around them and other undesirable environmental factors. However, despite their hygiene advantages (they are easier to clean and more resistant to physical influences), polymer packaging could be hazardous from a chemical point of view, meaning they could release harmful elements into the products they enclose. For tests the scientists took experimental samples of film, based on high-pressure polyethylene, but with different additives.

The chemists studied the properties of compressed polyethylene film with wax additives produced by NPO Plastpolymer and the Swiss Luwax, compressed film made with clay, coal, and iron sulphate additives, with zinc and aluminum oxides added, and polyethylene films obtained using extrusion. These films were held for 10 days in test solutions: water and lactic acid. Then the content of iron, zinc, aluminum, formaldehyde and other substances were determined in the solutions. After the ten days the films and the solutions displayed no changes whatsoever, yet this impression proved to be deceptive. Analysis showed that the composite film materials with polyethylene waxes and those films obtained from extrusion with subsequent treatment with ionizing radiation conformed to accepted standards and did not discharge harmful substances into the products that exceeded established norms. Films containing iron sulphate and zinc oxide emitted too many metals into the solutions, which is why they must not be used for food packaging. For packaging cheese the scientists recommend polyethylene with clay, coal and aluminum oxide additives, which have no effect on the cheese.