When it comes to avoiding germs on the job, perhaps President Obama is on to something with all the fist-bumping. Turns out, a new study published in the American Journal of Infection Control shows that knocking knuckles spreads 10 times less bacteria than shaking hands does, USA Today reports.

For the study, scientists at Aberystwyth University-Ceredigion in the United Kingdom systematically tested three common greetings for their germ-spreading capabilities: the handshake, the high five and the fist bump. They did this by getting a greeter to dip his or her gloved hand into a not-too-dangerous E. coli mixture in the lab and then exchange hellos with a clean-gloved receiver. Researchers then tested both gloves for bacteria.

Overall, handshakes were found to transmit about 10 times as many germs as fist bumps, with the firmest, longest embraces spreading the most pathogens between greeters. High fives turned out to be about half as germy as a handshake.

Critics are quick to point out that the experiment doesn’t quite mimic real life, since we have a far wider array of bacteria living in different concentrations on parts of our hands at one time. Others say the findings don’t necessarily come as a surprise, since shakes put far more surface area in contact than the other two greetings.

However, health advocates say it could help provide ammunition to those who think handshakes and other close-contact practices should be banned in hospitals and other places where germs can be a big concern.

Did you know that even gloved hands can transmit bacteria to your hands? Click here for the dirty details.