2023-06-14 02:09:58
When we buy food, we tend to focus our attention on the quality, taste and freshness of the products. However, we often overlook a component that plays a crucial role in the preservation and safety of these products: the container.
These vessels can be made from a variety of materials –plastics, paper, cardboard, metal, glass, adhesives, inks, varnishes…– that not only provide a attractive presentationbut also fulfill a series of fundamental functions for maintain the freshness, quality and safety of food that we consume on a daily basis.
To make them, you need to add chemical compounds –stabilizers, antioxidants, plasticizers, dyes, lubricants, etc..– that guarantee the functionality of the container. called additionscan be transferred to food by a process called migration affecting the safety and quality of food products. some may be harmful to health and even cause cancer.
It is logical, then, that this migration worries the food industry. It is important that packaging manufacturers comply with specific regulations and standards that set maximum migration limits for certain additives. These are evaluated from experimental tests that simulate the real conditions of use and contact between food and the container.
The NIAS problem
But What contaminants can the container contain? Answering this question is not easy, since there is a group of compounds called Not Intentionally Added Substances (NIAS) which, as its name indicates, are not intentionally added during the manufacturing processunlike additives.
These substances can come from different sources:
Byproducts. They are formed as a result of the production of the container. A clear example are the oligomers, generated as a consequence of polymerization. Through this process, two chemical groups react and join together to form chains of repeating units. It could be likened to stringing beads onto a very long string. But when these reactions occur, other smaller products are also formed, the aforementioned oligomers, which are incomplete chains. Continuing with the previous simile, they would be reminiscent of bead bracelets.
almost always are unwanted by-productswhich can reach the food and, on some occasions, contaminate it.
decomposition products. They are the result of the degradation of additives during the manufacture and use of the containers. Various investigations have shown the migration of degradation products of antioxidants commonly used in plastics.
contaminants. Coming from impurities of additives or compounds from the environment, they can remain in the final product and end up in the food.
Products of interaction between packaging and food. One of the CLICK most studied are the primary aromatic amines, which are formed by the reaction of monomers used in the polymerization of polyurethane-type adhesives with water. These adhesives are used to join layers of plastic that later form the base of many containers. An example is the plastics for vacuum packaging or the upper part of meat trays, which consist of several layers with different properties: gas and vapor barrier, heat sealing… Primary aromatic amines have been studied for a long time, since they are carcinogenic compounds. According to current European legislation, they must be checked before the packaging reaches the market.
In addition to the sources mentioned, the processing and recycling they can also introduce contaminants into food contact materials. In containers made with recycled plastics products from previous use have been found, such as flavorings absorbed by plastics or compounds from washing in the recycling process.
As indicated above, the safety of the containers must be guaranteed before launching them on the market through migration studies. However, NIAS, being mostly unknown substances, make their analysis difficult. This is a challenge from the point of view of analytical chemistry, since it is a very tedious, long and complex task.
However, in recent years there has been considerable progress in techniques to analyze NIAS. Thanks to them, multiple compounds have been identified that must be controlled in the packaging before being launched on the food market.
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