3M's Clean-Trace NG Luminometer uses adenosine triphosphate (ATP) bioluminescence to measure the level of potential contamination on a surface within seconds. Costing over $4000, the device is primarily used in hospitals to make sure patient instruments are clean. For SXSW, 3M swabbed festival goers phones and placed the swab into the luminometer, leading to a score in Relative Light Units, or RTUs, determining how much bacteria lived on the device being tested.

The result? My phone scored in at a moderate 404 RLUs, higher than the recommended score of 200 (but lower than some who hit the 2,000 mark). When traveling, it's not possible to be perfectly clean all the time, but one can always step their game up a bit. A simple disinfectant wipe (wrung out a bit to remove excess moisture) or a little mixture of alcohol and water spread on a damp cloth is more than enough to reduce that germ count. Before doing so, check the cleaning recommendations of your phone manufacturer so that if something goes wrong (say, liquid damage or a diluted oleophobic coating), you don't void your warranty.