Any little familiar with medicine will confirm that flowing water is sometimes hardly the only reliable way to combat microbes. And whoever wants to save "pay twice or even three times. And so you can not stop at what has been achieved, and get a device called the "shell for shellfish", as in enlightened Europe.
and...
Any little acquainted, will confirm that chemistry and thermal treatment are the only reliable ways to combat microbes. Therefore, normal people and meat and potatoes are cooked / roasted. The potatoes are washed, not so that the microbes are washed, but so that the soil is not boiled - it is tasteless, even if all the microbes have died there.