Technological learning and innovation sources in food industries -The technological and structural changes in the food industries during the last forty years have been the result of a technological learning, located in enterprises. The accumulation of scientific and technological knowledge is a long term process: three periods may be identified into this long evolution since the second part of the ninetieth century. There is an heterogeneity of learning activities, which make possible the distinction of five different types of firms. In each of them, there are different capacities to use external sources of innovation, due to the organisation of internal learning.
