California is the largest US producer of processing tomatoes, generating 96% of all domestic production and nearly 30% of global supply. Processing tomatoes are mostly processed into diced and paste products. Consumers and actors along their supply chains are increasingly interested in understanding their environmental burdens and identifying opportunities for improvements. This study applies life cycle assessment (LCA) to California diced and paste products over a 10-year timeframe to characterize current impacts and historical trends.

The LCA considers a scope from cradle-to-processing facility gate and accords with relevant Product Category Rules as published by the International EPD® System. Extensive primary data were collected for tomato cultivation for the years 2005 and 2015, and from processing facilities for 2005, 2010, and 2015 to understand the effects of evolving practices and technologies. We estimate crop and regional specific nitrous oxide and nitrate leaching emissions using a biogeochemical model, and the USES-LCA model is used to determine potential impacts from pesticide application. A suite of impact assessment categories is included based on the CML method (only global warming potential and freshwater consumption values are in the abstract).

The 2015 results of the study indicate that diced tomatoes are responsible for 0.16 kg CO₂e and 71 L of freshwater per kg, and paste is responsible for 0.83 kg CO₂e and 328 L of freshwater per kg. The main opportunities for improvement include natural gas use in the greenhouse phase, energy for irrigation pumping and fertilizer type in the cultivation phase, and natural gas and electricity use in the facility processing phase. These hotspots are consistent with studies of processing tomato in other parts of the world. Evaluating trends over time showed that technological improvements in the industry had reduced life cycle impacts; for example, global warming potential decreased by 12% for paste and 26% for diced products between 2005 and 2015.

Trends over time show increasing efficiency at the cultivation and processing facility stages that have led to reductions in all impact categories evaluated. However, additional opportunities exist beyond efficiency improvements. Fertilizer and pesticide choice are potential opportunities for further reducing impacts. Also, the introduction of renewables in each phase of the supply chain (solar-powered irrigation pumps and onsite solar energy generation for facilities) could reduce the overall supply chain GWP100 impacts by 9–10%.

Key words: canned tomatoes, carbon footprint, food supply chain, life cycle assessment (LCA), processing tomatoe, sustainability, tomato paste