Don't scrap the waste: The need for broader system boundaries in bioplastic food packaging life-cycle assessment - A critical review

The increasing amount of plastic waste generated each year, fuelled by the growing consumption of single-use plastics in food packaging applications, threatens the integrity of our ecosystems while creating an unprecedented waste management crisis. The biodegradable properties of some bioplastics have been identified as a promising solution to divert food and food packaging waste from landfill while avoiding plastic leaking into the environment. However, such bio-based biodegradable alternatives may not necessarily provide an improvement in overall environmental impact, especially when considering their efficacy at preventing food waste. This is the first systematic review to investigate the relationship between food packaging and food waste, based on conventional and biodegradable plastic food packaging life-cycle assessments (LCAs). It focuses on the trade-offs that may occur between food packaging production, end-of-life management and food waste prevention across the entire food packaging life-cycle. Following a review of 111 papers, 19 were identified for further investigation and data extraction. Quantitative analysis for five LCA impact categories, as well as hotspot analysis and end-of-life scenario analysis for global warming potential were conducted. The resulting picture is conflicting and suggests that though bioplastics display environmental benefits for global warming potential and non-renewable energy use, these are often negated by the agricultural inputs required for bioplastics raw material production. While the LCAs included in this study do not provide enough evidence to state which polymer is best at reducing food waste, they emphasise the environmental footprint associated with food production and food waste, and highlight the importance of including the food itself in food packaging LCAs. Therefore, focusing on food packaging performance in food waste minimisation is critical. We found that bioplastics provide the benefit of diverting biodegradable waste from landfill or incineration to 'greener' streams such as anaerobic digestion and composting, contributing to a circular economy. Encouraging biodegradable bioplastics should target plastic packaging where effective recycling measures are failing due to the challenges that remain for treating and recycling materials made of multiple, highly food-contaminated layers. The bioplastic industry is still young and optimising both the manufacturing process and material biophysical properties would contribute towards improving the overall environmental profiles of bioplastics. (C) 2020 The Author(s). Published by Elsevier Ltd.