Fermentation in the presence of UV light
Depends on the wavelength. Fermentation is basically metabolic activity by yeast and bacteria. UV-C (&lt;280 nm) is pretty good at killing a lot of micro-organisms. Some species are more resistant than others, but it's safe to say that exposure to this kind of light will probably interfere with fermentation. Depending on the medium and how the light is applied (thickness of material, power, etc.), it may have more or less of an effect depending on how much light reaches the yeast or bacteria.