I was thinking along similar lines. I don't think the particular NSF protocols mentioned on that page (53 and definitely not 58, which applies to RO) can accomodate UV products. There's an NSF 55: Ultraviolet Microbiological Water Treatment Systems protocol, however I'm not sure if that applies to personal purification products or just larger products for municipal use. And I'm not sure if NSF 55 mentions crypto.