Adding ozone to the process water kills bacteria and stops discolouration of the water. This method can be used for water buffer channels where the water sits for a long time and is continuously contaminated. When the water comes into contact with the fruit, the bacteria and contamination are passed on to the fruit. Treating this water with ozone kills the bacteria, which makes it possible to use the water for longer without it having to be refreshed. Also, the storage life of the fruit is extended, because the fruit does not come into contact with extra bacteria.