Material Protection
Functional layers incorporated into packaging prevent the migration of moisture, oils, chemicals and gases between the product and the external environment. A food contact barrier ensures that substances from the paperboard or the printing inks do not contaminate the edible contents. These layers can be made of polymers, aqueous coatings, metallic foils or waxes.
The effectiveness of the shield is measured by the rate at which specific molecules pass through the material over a set time.
Barrier Mechanism
Physical blockages stop the movement of mineral oil saturated hydrocarbons and mineral oil aromatic hydrocarbons which are often found in recycled fibers. A high quality barrier maintains its integrity even when the board is folded or creased. Some barriers work through surface tension to repel liquids while others use a dense molecular structure to trap gases.
The choice of material often depends on whether the food is dry, fatty, chilled or frozen. Moisture vapor transmission rates provide the primary metric for evaluating how well a barrier will protect sensitive goods like biscuits or powders. Migration limits are tested using food simulants in a laboratory setting.
Safety Requirement
Regulatory bodies like the efsa or the fda mandate that these materials meet strict safety standards. Testing involves submerging samples in food simulants to measure the extraction of prohibited substances.
