ULTRAVIOLET CHEESE PRESERVER

[Don42]

I’ve found that foods keep for a very long time in the fridge when vacuuum-sealed in “foodsaver” bags which are heat-sealed or welded shut after most air is evacuated.

However, cheese eventually molds, even when protected this way. I’d noticed that cheese doesn’t mold in the original wrapping at the store, so I wonder if killing mold spores in the package after sealing it might result in the cheese lasting a lot longer.

I found a CFL germicidal UV-C lamp at a surplus place. It is a CFL15UV/MED and it appears that these lamps or bulbs are readily available. They have self-contained electronic ballasts so they need only be screwed into a standard E-27 117-volt household light bulb socket to operate.


They produce germicidal UV-C radiation at 254 nanometer wavelength. The UV output of this 15-watt bulb is about 3.6 watts. If this output is directed into an area of 8” x 10” (about 500 cm2) with 60% efficiency, the resulting irradiance is 7200 microwatts per cm2. A 15-second exposure would be a dose of 108,000 microwatt-seconds per cm2, easily enough to kill mold spores.

To accomplish this, and to protect my eyes and skin from the UV radiation, I needed to make a reflector and housing. I made it of polished aluminum. It fastens directly to the lamp itself. The socket with power cord then screws onto the lamp.
This is an aluminum-brazed assembly. The material is 18-gage (.040”) aluminum. I used an oxyacetylene torch to do the brazing.