By Nicole Bell, Center for Sustaining Agriculture and Natural Resources, Washington State University
This article is part of a series, Climate Friendly Fruit & Veggies (see sidebar), highlighting work from the Fruit & Vegetable Supply Chains: Climate Adaptation & Mitigation Opportunities project, a collaborative research study co-led by investigators at the University of Florida and the Agriculture & Food Systems Institute. Other collaborators include researchers at the University of Arkansas, University of Illinois, the International Food Policy Research Institute, the World Agricultural Economic and Environmental Services, and Washington State University. This project seeks to identify and test climate adaptation and mitigation strategies in fruit and vegetable supply chains.
Efforts to quantify the carbon footprint of agriculture are often focused on the greenhouse gas emissions resulting from on-farm activities, mostly from fertilizer production and the energy required for use of farm implements. While you, as a climate change-conscious consumer, may place your attention on the environmental impact of your food before it arrives in your grocery bag, a recent study published in the Science of the Total Environment examined the relative impact of different parts of the supply chain (on-farm, processor, retail, and consumer) for potato and tomato products, both fresh and processed. Study authors from the University of Arkansas, led by Ranjan Parajuli, assert that the way food is prepared presents a significant opportunity to reduce greenhouse gas emissions. If the goal is to reduce the overall environmental foodprint, changing the way potatoes are cooked may make more of a difference than how the potatoes themselves were grown.
Consumer demand for sustainable farming practices have been a driver in the creation of organizations like the Potato Sustainability Alliance, allowing growers, processors, and major buyers like McDonalds and Sysco to collaborate and ensure certain environmental standards are followed at the farm level. There appears to be a missing puzzle piece, however, in terms of recognizing the influence of parts of the supply chain after products leave the farm gate, including the impact of the consumers themselves.
A “cradle-to-grave” life cycle assessment, or LCA, can give us a better idea of the impact of different parts of the supply chain. In this particular study, researchers used the LCA method to follow the movement of a common American favorite, the potato, through its entire journey from seed at planting to potato peel in the compost. The benefit of this type of analysis is that an LCA can uncover impacts throughout the production and consumption process that are often overlooked. Rather than simply examining the environmental impact of on-farm production inputs, cradle-to-grave LCA examines the wide range of points along the supply chain, including impacts resulting from the transport to retail, electricity used at retail, food preparation methods, and bio-waste treatments.
As it turns out, the biggest opportunity to reduce greenhouse gas emissions in the life cycle of a potato occurs when the decision is made about how to prepare said potato. Parajuli and his colleagues examined various processed potato products (chips, frozen fries, and dehydrated potato), and found that frozen fries had the highest greenhouse gas emissions, with 38% of the total emissions occurring during the consumer stage of the supply chain. The farming stage, on the other hand, accounted for a mere 18% of the total greenhouse gas emissions (Figure 1). So how does this result show there are opportunities for reducing the carbon footprint? The carbon dioxide equivalent, or CO2-eq, is the unit used to measure that carbon footprint. French fries are generally par-fried prior to being frozen at the processor, then fried again at a restaurant or other food service establishment (which is considered part of the consumer stage in Fig. 1). When fries are oven baked instead of a second deep frying step, the result is a 19% reduction in total greenhouse gas impact.
What makes the difference? When it comes down to baking versus deep frying French fries, it’s the vegetable oil. The short bath that potatoes take in oil when prepared for consumption accounts for 18% of the total greenhouse gas emissions calculated for the entire life cycle of the French fries. What do these insights mean for the future of the French fry, and what does it mean for sustainability of the potato? For organizations like the Potato Sustainability Alliance, the efforts to reduce emissions and environmental impact up until the potato leaves the farm are worthwhile. As this study shows, though, the pressure to make agricultural production and farming practices more sustainable should be met with equal attention to stages of the supply chain that occur after products leave the farm, including education of consumers and the food service industry on the way food preparation influences the overall environmental impact.
It’s unclear whether cutting out the French fry’s second bath in oil will result in a product that is acceptable to consumers. However, given the potential benefits this question warrants further exploration by food service establishments interested in catering to climate conscious consumers. The results of this study indicate that there are numerous opportunities to reduce the environmental footprint of a particular food product beyond the farm gate, including reducing secondary packaging materials and food miles, as well as mitigating food waste. While it will be important to consider the logistical implications of any change on the supply chain, the good news is that food preparation offers one opportunity to make French fries that are better for the health of the consumer as well as the health of the planet.
The Fruit & Vegetable Supply Chains: Climate Adaptation & Mitigation Opportunities project (https://foodsystems.org/what-we-do/nutrition/fruit-vegetable-supply-chains/) was supported by USDA-NIFA Award No. 2017-68002-26789.
Parajuli, R., Matlock, D.M., Thoma, G. (2021). Cradle to grave environmental impact evaluation of the consumption of potato and tomato products. Science of the Total Environment, 758, 143662-143662.
This article is also posted on the CSANR Perspectives on Sustainability blog.