Bogus water Purifier now live on KS...

[Khendrask]

https://www.kickstarter.com/projects/572058660/orbtm-the-worlds-first-germ-killing-uv-light-ball

I use several UV water sterilizers, and I don't even have to crunch the numbers to know that this is 100% bogus.  Just from that fact that if it were even slightly effective, it would blind anyone that used it in short order.  UV purification uses extremely high intensity UV, and great pains are made to ensure that the sources can never be energized unless completely enclosed the the opaque (metal) chamber.

The UV "Air Purifiers" you sometimes see as florescent tubes in ceilings are also non-effective, as even though they are much higher power then this "Ping Pong Ball", they don't actually produce much in the spectrum of organism damaging UV radiation.

[m98]

I wouldn't go as far saying that the product is bogus, I personally have some experience in the field and even a single comparably low-power UV LED can be quite effective at sterilization. So their claims sound quite reasonable. However, I would not even want to go to the same country those things would be used in regular households because they just ask for accidental corneal damage.
The more probable answer might be that they're not using actual UV light, but rather intense blue light at around 415 nm, which also works as a disinfectant because it exerts phototoxic effects in many microorganisms. It also isn't as dangerous to the eyes, because you can simply look away as you'd do with any other bright light source. There's still an accumulated damage to the retina so I wouldn't be putting that in my fridge anytime soon.

And how'd you know, just read the Kickstarter comments:

We are waiting on exact wavelength data from our engineers, but we expect the Orb to peak around 405nm, just outside UVA range.
Note that we are FDA Cleared to produce Class II Medical Devices, and we have been producing devices that kill acne-causing bacteria for many years. These devices use 415nm blue lights that are medically proven to kill bacteria. Our 405nm Orb lights should be even more effective. Note also that dermatologists (doctors) have been using blue light therapy for years on acne.

[thm_w]

I would be concerned if someone took this ball and put it in their shoes then tossed it in with the vegetables. But then again you will end up washing those vegetables anyway.

Here are some studies:
https://www.ncbi.nlm.nih.gov/pubmed/20662022
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2663198/

The second used an array of 100 LEDs, and many of the bacteria were killed (one was not). However, it took between 30-50 minutes for this to occur.
They state at max output its on for 5 minutes every hour, not much. Would pulsing a few minutes have any useful effect at all then?
Without knowing the relative light intensities its hard to say, the study is from 8 years ago so LED efficiency would have increased, but I suspect not 10x.