As a geographer, my work spans the fields of political ecology, cultural economy and science and technology studies (STS). Much of my research has centered on food supply chains in and between different parts of the world. Although different projects have focused on different geographic regions and scales, one of my enduring concerns lies in the expert knowledge and social relations that get food from farm to market.  I am especially interested in the work, technology and politics involved in defining and assuring certain qualities in food and agriculture, such as fresh, fair and sustainable. In recent research projects, for instance, I have studied contemporary debates about how best to measure food's environmental footprint, as well as the ongoing efforts of large food companies to assess and improve the sustainability of farms supplying their raw materials.

My past projects have resulted in two books. French Beans and Food Scares: Culture and Commerce in an Anxious Age (Oxford, 2004) compares the "cultures of commerce" of two fresh vegetable trades between Africa (Burkina Faso and Zambia) and Europe (France and Britain). The story is less about food scares per se than about how the relationships and technologies of globalization are culturally and historically constituted. In Fresh: A Perishable History (Harvard, 2009), I trace how the meanings of freshness in food have changed along with the technologies that are supposed to protect it. While much of the book focuses on the late 19th and early 20th centuries, it aims to shed light on today's appetites for this ephemeral food quality.