The weak bond holding ozone's third oxygen atom is what causes the molecule to be unstable and thus, very effective.

An oxidation reaction occurs upon any collision between an ozone molecule and a molecule of an oxidizable substance (i.e. bacteria, fungi (mold & yeast), viruses, forms of iron & manganese…)

The weak bond splits off leaving oxygen as a by-product. During an oxidation reaction, organic molecules are changed and dissolved metals are made no longer soluble.