PURPOSE: To keep the freshness of fresh vegetables and fruits even at normal temperature, by coating the vegetables, etc. with a freshness-keeping liquid containing a film-forming material, a mildew-proofing and rot-proofing agent, etc., thereby forming a coating film to the surface of the vegetables, etc.

CONSTITUTION: For example, in the case of the freshness-keeping treatment of lettuce, a definite amount of a diluted freshness-keeping liquid (a mixture of wax, synthetic resin, freshness-keeping agent, mildew-proofing agent, preservative, fungicide, alcohol, etc.) is supplied from the mixing tank 4 through the pump 5 and the pipe 5' to the tank 3, and the lettuce A transported by the conveyor 2 is immersed in the liquid to form the coating film of the freshness- keeping liquid on the surface of the lettuce A, and then, the excess liquid is separated and removed by the centrifugal separator 6. The cut end A' and the core 2A of the lettuce A are coated with a freshness-keeping paste 1', and the treated lettuce is packaged with a piece of paper impregnated with a peroxide, a zeolite paper 7 or polystyrene paper 8.