Processors and manufacturers occupy only one sector in the complex marketing chain for food between agricultural producers and consumers. Until recently political economy accounts of agriculture and food were relatively silent on the non-food industry sectors, such as food retailers, relying on an assumed relationship between mass food production, on the one hand, and class-based food consumption on the other hand. Clusters of stalls selling farm produce can still be found in open village squares and covered city markets throughout developed and developing countries alike where face-to-face trading continues. A recent trend has been for electronic markets to threaten the metropolitan wholesale and auction wholesale markets for the buying and selling of agricultural products, including livestock, fruit, vegetables and flowers. Fast-food chains from the USA, such as Burger King and McDonalds, have emerged as the most recent innovators in how food is retailed to largely urban consumers, placing particular contractual demands on the suppliers of their raw materials.