To provide a food washing technique enabling food to be washed without causing a foaming due to salt content with high dirt decomposition and removing effect and degerming effect while clearing the regulation of Food Sanitation Law by using both salt-free alkaline electrolysis water and acidic electrolysis water as washing water for use in washing machines.

This food washing technique (method) comprises pouring air foams on food by using the alkaline electrolysis water and acidic electrolysis water. Both kinds of the water to be used as the washing water are produced by the following process: using a water electrolyzer 5 constructed in such a manner that raw water W is passed through an anode chamber 5a and cathode chamber 5b and an electrolytic aqueous solution D is contained in an intermediate chamber 5c and an electrolytic treatment is then made to feed the electrolytic aqueous solution to the raw water by electrophoresis, the acidic electrolysis water is obtained in the anode chamber while the alkaline electrolysis water in the cathode chamber. The alkaline electrolysis water W4 discharged from the anode chamber is used as the washing water for a first washing machine 1, while the acidic electrolysis water W3 from the cathode chamber as the washing water for a second washing machine 7.