His work focuses on modern religion and consumer culture in Southeast Asia and Europe. More specifically, Johan explores the interfaces between class, consumption, market relations, Islam and the state in a globalized world. He is the author of Proper Islamic Consumption: Shopping among the Malays in Modern Malaysia (NIAS Press 2008), The Halal Frontier: Muslim Consumers in a Globalized Market (Palgrave Macmillan 2011), Islam, Standards, and Technoscience: In Global Halal Zones (Routledge 2015), the co-edited volume Halal Matters: Islam, Politics and Markets in Global Perspective (Routledge 2015) and the co-authored Between Religion, Regulation and Consumption: Globalising Kosher and Halal Markets (Manchester University Press 2016) as well as numerous articles in journals and edited volumes.