As a last resort I ordered this ionizer, although I could not believe it really. But: It works! After just one night the smell subsided greatly; now we can use the freezer again. If you put into keeping the nose, is a faint residual perceptible, but this is not broadcasting on food or ice cubes. The ionizer apparently works perfectly well at temperatures lower than -10 ° C. Let's see how long do the batteries.
Even in normal refrigerator the effect is clear: Even unpackaged mature cheese is not smelled. Whether foods are also more durable, we have not tried. But I consider it possible. We are thrilled and grateful of the little device that there is such a thing!
Addendum after three months: The ionizer is still working with the first set of batteries! And at minus 15 degrees. The freezer without smell and normally available. Toll!