Advancements in recycled plastic food packaging safety and suitability: Addressing chemicals of concern (CoCs), recycling policies, material processing and performance

Abstract

The ever-growing nature of plastic production and the accompanying surge in plastic waste bring on an irresistible challenge where plastic recovery and recycling could be vital solutions to combat this catastrophe. While new regulations offer promise for battling this situation through mandatory utilization of recycled plastic in new product manufacturing, the lack of knowledge regarding their chemical safety hinders their full potential. For example, their application as raw material for direct food contact material (FCMs) is challenging without enough information on chemical safety. Therefore, exploring the challenges in post-consumer plastic recycling systems, particularly for high-value applications such as FCMs can shed some light on this field. A comprehensive evaluation of global plastic recycling policies, chemicals of concern such as phthalates and bisphenol, and the identification of intentionally and non-intentionally added substances in post-consumer recycled (PCR) plastic, especially for polyolefins, a common plastic in packaging products are an urgent need. While the urgency for safety and quality evaluation in PCR plastic is undeniable, exploring the challenges in the recycling chain/framework itself is also imperative. Developing a recycling system that assures minimal contamination, cost-effectiveness, sustainability and high-quality plastic generation is essential. The review of EPR policies and regulations provides insight on how the regulations, mandates, and policies influence recycling rates and producer accountability through fees, taxes, and landfill bans. This dissertation compares PCR plastic from material recovery facilities (MRFs) against virgin plastic and compares food and non-food application PCR plastic. The MRF recovered PCR plastic contained higher concentrations of phthalates and bisphenols than virgin plastics, although all samples complied with the Toxics in Packaging Clearinghouse (TPCH) regulations. One crucial focus of this dissertation is to identify intentionally added substances (IAS), non-intentionally added substances (NIAS), and other chemicals of concern (CoCs) and assess their impact on the safety of recycled materials. The Cramer classification system highlights a slightly higher proportion of high-toxicity Class III compounds in PCR polyolefins, especially higher in non-food application PCR polyolefins (polypropylene), emphasizing the need for regular monitoring. Several analyses have been performed to understand the different thermal, physical, and molecular properties of different sources (e.g., food and non-food applications). Another essential aspect addresses the influence of different washing techniques and the recyclability of the wash water during plastic recycling at the recycled plastic recovery/processing facilities. The findings enumerate the importance of surfactants in post-consumer plastic wash water and the implication of ultrasonication in improving phthalates and bisphenols' cleaning efficiency. At the same time, it also generates contaminated wash water with phthalates and bisphenols, underscoring the importance of adequate water treatment before reuse or disposal. Compiling restricted substance list (RSL) from publicly available RSLs provides critical insights into emerging CoCs, their regulatory thresholds, and potential health risks. This RSL would serve as a framework for converters, brand owners, and regulatory decision-makers and help analyze chemical migration risks for food application plastics. This dissertation improves our understanding of the recycling system, strategy, material composition, regulatory compliance and points towards the limitations in current recycling systems and scientific information. The findings identify the need for optimizing post-consumer plastic washing techniques, refining recycling methods, and implementing progressive policies to generate a clean recycling stream, ensuring safety, efficiency, and sustainability in FCM applications. This work is a valuable resource for researchers, manufacturers, and policymakers in reducing plastic waste, increasing utilization in direct food contact applications, and promoting a circular economy. This research's impact is understanding the CoCs in post-consumer plastics, emphasizing the need for improved plastic recycling frameworks and more effective decontamination techniques. Based on the findings of this work, future research should investigate effective washing techniques in lessening CoC contamination without affecting the material's physical properties with more sustainable surfactants to improve the quality and safety of PCR plastic streams.