A method of preparing an ultra-cleansed lactoferrin preparation, termed treatment for contaminant reduction (TCR) is provided which includes the steps of treating commercial lactoferrin preparation with at least one each of surfactants, antioxidants and polyphenols to form purified lactoferrin (LF-TCR) and drying the LF-TCR. Additionally a therapeutic lactoferrin composition is provided which contains LF-TCR and optionally surfactants, antioxidants, polyphenols, tissue/membrane diffusion facilitating agents and anionic compounds. The therapeutic lactoferrin composition can additionally contain bioactive agents, dietary supplements, nutraceuticals/functional foods, prophylactic agents, therapeutic agents and probiotic lactic acid bacteria.