Increasingly, over the past ten years, people--- especially young people –have become aware of the need to change their eating habits, because much of the food they eat, especially processed food(加工过的食品), is not good for the health. As a result, there has been a growing interest in natural foods: foods which do not contain chemical additives(添加剂) and which have not been affected by chemical fertilizers(化肥), widely used in farming today.