PURPOSE: To recover the freshness of a food or drink and delay oxidation, by laminating plural doughnut-shaped permanent ferrite magnets on the outer periphery of a cylindrical body formed of a nonmagnetic material to bring the same poles into contact with one another and passing the food or drink through a space having an effective magnetic flux density.

CONSTITUTION: Plural doughnut-shaped permanent ferrite magnets 4, 4... are fitted on a cylindrical body 1 which is a nonmagnetic material made of rigid plastic, etc., to bring the same poles into contact with one another and both annular nuts 2 and 3 are screwed in. Continuous compressed magnetic fields are present in the interior of the cylindrical body 1 and a space 5 having an effective magnetic flux density over the whole region is provided. When a body is passed through the space 5, eddy electromagnetic waves flow by the electromagnetic inducing action to improve the taste of a food or drink and delay the oxidation.