Contribution of consumer practices to the environmental impacts of pizzas

Abstract

The production and consumption of food are responsible for high environmental impacts. While the impacts of the agricultural production of food have been widely studied, less is known about the environmental effects associated with household food preparation by consumers. This study thus had two main goals: to (i) evaluate the influence of consumer practices at home on the environmental impacts of a food product, (ii) to compare the environmental performance of a single type of food prepared using different manufacturing methods (industrial, homemade, and assembled at home). These environmental profiles were also compared to consumers' perceptions and preferences regarding these products. Pizza was chosen as a study model. Sixty-nine participants were recruited to prepare, consume and evaluate six pizzas at home (one ham-and-cheese pizza and one mixed-cheese pizza, prepared using each of the three methods). Participants were asked to complete questionnaires related to their habits, the preparation of the six pizzas, and their perceptions and preferences. Their answers were used to assess the environmental impacts of the pizzas via life cycle assessments (LCA) in SimaPro software using two different functional units (FUs): one pizza and 1 kg of pizza. Our results revealed that consumer practices can vary greatly among consumers which has a significant influence on the environmental impacts of pizza. For both FUs studied, the responsibility of the recipe and of the manufacturing method are preponderant on certain indicators of the environmental profile. Thus the manufacturing method has a decisive influence on the values of the indicators sensitive to electricity consumption. Consumers tend to prefer homemade pizzas and think that they have less impact on the environment, which is not necessarily in line with our results. This study demonstrates the importance of incorporating consumer practices into environmental assessments of food products in order to adequately describe their environmental impacts.

Introduction

Reducing the environmental impacts of human activities is one of the major challenges of the 21st century. In 2015, the United Nations established 17 sustainability goals, of which one was “responsible consumption and production” (United Nations, 2020). Production and consumption of food for human use contributes to 20 to 30 % of environmental impacts worldwide (Tukker et al., 2006). For this reason, numerous studies have focused on environmental assessments of food products, with the goal of finding ways to decrease their impacts. Life cycle assessment (LCA) is a well-recognized approach that is widely used by the research and business communities as well as public authorities. It has been standardized in the ISO 14040 to ISO 14044 standards (EN ISO, 2006) and is recommended by the European Commission in the Product Environmental Footprint (PEF) framework (2013/179/EU Commission Recommendation). This multi-criteria assessment method takes into account the entire life cycle of a product and is generally the chosen method when it comes to assessing the environmental impacts of food products (Cucurachi et al., 2019).

The majority of studies on the environmental impacts of food products have concluded that agricultural production is a main contributor to the final product environmental impacts. For example, Weidema et al. (2008) showed that livestock breeding made the single largest contribution to the environmental impacts of dairy and meat products. Similarly, Dijkman et al. (2018) reviewed studies focusing on the environmental impacts of meat, cheese, and bread, and concluded that the agricultural stage was a major hotspot. However, the food consumption step—in other words, the activities related to the use of the food by consumers (including for example home storage or cooking)—is frequently excluded from the scope of the studied systems, generally due to a lack of data. This introduces a comparison bias between products that are manufactured completely outside of the home and those that are manufactured (at least in part) in the home. An exception to this is found in the study of Sonesson et al. (2005), who included the use step in a comparison of the environmental impacts of the same meal produced in different ways: homemade (prepared by boiling, frying and baking), semiprepared, and ready-to-eat microwave preparation. Those authors concluded that, in terms of environmental impacts, the overall differences among the three types of meal preparation were small: the ready-to-eat meal consumed the most energy but the homemade meal had a higher impact on eutrophication and global warming. That study did not address, however, the effect of variability in consumption practices, such as the use time of household equipment, on the final environmental impacts of the product. Instead, Gruber et al. (2016) studied the environmental impacts of potatoes, rice, and milk studied in three different scenarios of consumer behavior: a base scenario (including, e.g., transport by car and cooking in an uncovered pot with heat reduction after boiling point), a conscious scenario (e.g., transport by walking and cooking in a covered pot with heat reduction after boiling point), and a careless scenario (e.g., transport by car and cooking in an uncovered pot without heat reduction after boiling point). The results showed that the use step can become the main contributor to the environmental impacts of food products when using the careless scenario which means that the consumer practices can have a strong influence on the product environmental impacts.

A strong influence of consumer behavior on the environmental impacts of food was also highlighted by Matar et al. (2020) in a study of 132 scenarios of home storage of strawberries. In particular, the authors reported that the consumers' habit of opening the packaging before storing berries at home undermined the environmental benefits of modified atmosphere packaging in reducing food waste.

Consumer practices can differ from one household to another for several reasons, one being the type of household equipment available. For example, in France in 2015, 61 % of households had a dishwasher and 84 % owned a car (INSEE, 2019). However, practices regarding food can be shaped by many other factors such as habits or compromises with other constraints (e.g., time constraints). Consumers are increasingly attentive to the environmental impact of the food products they consume (Esmailpour and Rajabi, 2018), even if this is not usually considered a main criterion for food choices (Campbell et al., 2016). However, consumer knowledge regarding the environmental impacts of food is globally low. For example, Macdiarmid et al. (2016) highlighted a lack of consumer knowledge about the link between meat consumption and environmental impacts. Similarly, consumers tend to underestimate the energy consumption and greenhouse gas emissions associated with their food (Camilleri et al., 2019). Therefore, the way in which consumers perceive the environmental impacts of food products might not be consistent with the actual environmental performance. For this reason, it is important to have and disseminate informative data on the impact of consumer practices on the environmental impacts of products, and to understand consumers' perceptions of these impacts in order to help them make more environmentally friendly choices.

The goal of the current study was to investigate the influence of real consumer practices on the environmental impacts of a food product. Pizza was chosen as the study model, for three main reasons. The first is that pizza is a product that can be prepared in different settings, such as in an industrial facility or at home, and each method is associated with different practices at the use step. The second reason is that pizza is particularly appreciated in France, where its consumption is about 10 kg per capita each year; indeed, France has the largest per capita consumption of pizza in the world, along with the USA (PIC International, 2020). The third reason is that our team has already assessed the environmental impacts of 80 industrial pizzas (Cortesi et al., 2022a; Cortesi et al., 2022b), which provided a strong basis for the methodological choices in this study.

Here, different methods for preparing pizza—industrial, assembled at home from industrial ingredients, and homemade—were assessed by LCA, together with the variability in use practices of 69 consumer households. Consumers' perceptions of the environmental impacts of the different pizzas were also investigated in order to identify whether or not these were consistent with the environmental impacts calculated by LCA. Finally, data on consumers' overall appreciation of the different pizzas and perceptions of their impact on health were evaluated so that these could be compared to the perceptions of environmental impacts.