The Role Of Non-Intentionally Added Substances In The Safety Of Plastic Packaging

Friday, December 21st, 2018

Non-intentionally added substances (NIAS) refer to substances that are unintentionally incorporated into plastic packaging through a variety of processes such as the interaction between ingredients, degradation of material components or from impurities within the raw materials. And when researchers from SCIEX and the University of Almeria used non-targeted screening and high-resolution mass spectrometry to analyse plastic food packaging, it was found that two commonly used plastic packaging materials, polyethylene and low-density polyethylene (LDPE), possess multiple NIAS with moderate or high toxicity. Thus, both products should be used in limited quantities in food packaging.

Over one third of all food packaging comprises materials that are made from plastic. In order to ensure the continued use of plastic packaging in food, the packaging used must be safe for contact with food products and must not cause contact contamination. This includes the non-intentionally added substances (NIAS) within plastic packaging, as these substances might contribute to chemical contamination through a process known as food contact migration. This is caused when materials or chemicals from the internal face of the packaging or from other sources diffuse and come into contact with the food stored within.

In fact, food contact migration has been reported as one of the largest sources of food contamination, and occurs at rates approximately 100 to 1000 times higher than contamination caused by pesticide residues. In other words, there is a higher chance that food will be contaminated through toxic substances present within its own plastic packaging than by external sources. The potential health implications that plastic contamination poses to the consumer have resulted in the regulation of plastic materials in multiple countries. For example, the European Union has issued Regulation EU 10/2011, which has established specific rules for what plastic materials can be utilised in food packaging, as well as the specific compounds that are permitted for use in plastic formulations and manufacturing. Although NIAS are often not permitted above trace levels in food, they can still be introduced through a variety of processes. Highly sensitive and advanced analytical techniques, such as mass spectrometry, are needed to test samples for the presence of NIAS.

A study conducted by SCIEX and the University of Almeria found that in the case of polyethylene and LDPE, most of the NIAS contained within the materials have not been identified by the EU regulations. The study used SWATH acquisition – a type of non-targeted screening – in conjunction with high-resolution mass spectrometry, to screen foods in contact with the plastic packaging materials, following procedures established by the EU Regulation 10/2011. Only seven of the identified NIAS compounds were within the low toxicity range according to Cramer rules, while the remaining 19 were of moderate or high toxicity. This means that due to the potential toxicity that these compounds pose, their presence in plastic packaging for food could generate health risks for consumers. In particular, the polyethylene-based material could pose a higher risk to consumers compared to the LDPE material due to the high contact migration of caprolactam – a highly toxic nylon monomer – into the tested food.

It can be deduced from the study by SCIEX that in order to protect consumers from toxic food contaminations, it is crucial to evaluate the concentration and toxicity of NIAS in food contact materials as well as evaluating the toxicity of the materials themselves. Only through a non-targeted screening approach can the breadth of NIAS in food packaging materials be fully understood.