Cradle to grave environmental impact evaluation of the consumption of potato and tomato products

Abstract

This study discusses the environmental life cycle impacts of potato and tomato supply chains in a “cradle-to-grave” perspective. The principal focus is to evaluate the processed products, while fresh products are also briefly discussed. Processed products included are potato-chips, frozen fries and dehydrated flakes, and tomato-pasta sauce. The functional unit (FU) is 1 kg product(s), eaten at the consumer stage. Life cycle assessment (LCA) modeling has utilized multiple mechanistic crop models to estimate the crop yields, crop nutrient uptakes and irrigation water requirements. The farming systems represent the primary crop reporting districts where the selected crops are produced on a commercial scale in the United States. The post-harvest system was constructed utilizing the data collected from a processing plant and from other available studies. LCA modeling also constituted handling of co-products (e.g. starch in potatoes) and biowaste. A wide range of environmental impact categories were selected for the evaluation, which showed environmental differences between fresh and processed products. For instance, global warming potential for potato-fresh, chips, fries and dehydrated was 0.97, 0.85, 1.21 and 0.65 kg CO2-eq/FU respectively. For fresh tomato and tomato sauce, it was 0.74 and 1.5 kg CO2-eq/FU respectively. Likewise, fossil resource scarcity for fresh potatoes was higher than chips and dehydrated flakes, but lower than fries. Water consumption was slightly higher in fresh potatoes compared to the processed products. Similar impact patterns were found in fresh and processed tomato products. For most of the impact categories, processing and the agriculture systems were the major contributors. The contribution from the consumer stage varied with the ways the product is prepared, e.g. whether fries are oven heated or deep-fried in oil. Environmental mitigation measures include, the use of drip irrigation (for potatoes), and reducing: food miles, food waste and the use of secondary packaging materials.