For the first time, the peculiarities of the accumulation of contaminants by white root crops zoned in Ukraine were established. It has been established that the content of heavy metals, radionuclides, and nitrates in white root crops did not exceed the maximum permissible concentrations. It has been proven that the studied white roots have a high content of oxalic acid and its salts, as well as psoralen. The oxalate index of parsley is 1.3–1.7, parsnip and celery—3.3–4.0, with a norm of less than one. The most psoralen is contained in parsnip—up to 53 mg%, in parsley—up to 38 mg%, and in celery—up to 30 mg%. Using mathematical modelling of the process of raw material processing, scientifically based methods of reducing contaminants in white root crops were obtained for the first time. These methods consist of keeping cubed root crops in a solution containing 2.0% potassium chloride and 1.0% sodium bicarbonate for processing parsnips and parsley, and 1.0% and 1.5% for celery, respectively. Keeping parsnips and parsley should be carried out at a temperature of 20 ºС, and celery at 30 ºС. Processing time is 20 min for parsnip, 40 min for parsley, 30 min for celery. The proposed methods differ from their analogues by being more efficient and versatile. They help to reduce the content of psoralen by 19.9%–30.0%, the content of nitrates by 45.5%–80.0%, and the content of oxalic acid and oxalates by 30.0%–50.0%.