The disclosure relates to a method of cleaning a food plant of the type which produces an aseptic producr or a product with extended shelf life. The method comprises at least one and preferably two circualtions with an alkaline detergent solution (2, 12) and at least one and preferably two circulations with an acidic cleaning solutions (4, 14). The circulations take place alternatively with the alkaline detergent soluton (2, 12) and the acidic cleaning solution (4, 14). Prior to the first circulation (2), between each circualtion (2, 4, 12, 14) and after the last circualtion (14), rinsings with water take place (1, 3, 5, 13, 15). Simultaneously with the last circulation with alkaline detergent solution (12), the plant is sterilised and after the last circulation with the acidic cleaning solution (14), and the two last rinsings with water (13, 15) take place with sterile liquid.