Jimmy Smith, a lead economist from the World Bank Institute is working in Poverty Reduction and Economic Management in Africa. At the Tropentag conference in Zurich, he was talking about the role of livestock for the world food system. What was very important to the speaker, was the definition of food security. According to him, food security exists, when all people at all times have physical and economic access to sufficient, safe and nutritious food that meets their dietary needs and food preferences for an active and healthy life. Since lifestyles have changed during the past decades in developed countries as well as in developing countries, there is a enormous gain in consumption of different foods like milk, meat or crop. A problem is the availability and accessibility of those foods in developing countries. As feeding people does not nourish them, it is important to increase the accessibility of markets, so those people who are directly or indirectly depending on livestock for their livelihoods are able to nourish themselves. There are different opportunities and challenges that must be faced, like the discounting of domestic markets, different types of emissions that are caused by agriculture or the human-animal health, which, according to Jimmy Smith, should be linked to the so called "one health".