The findings, published in the American Journal of Infection Control, showed a handshake transferred 10 times as many bacteria as a meeting of fists, while a palm-to-palm high-five was somewhere in-between.
It is thought the smaller area of contact and shorter duration in the bump reduced the spread of bacteria.
Dr Dave Whitworth told the BBC News website: "There is definitely a serious side to this story, superficially it is very whimsical, but there is a serious message underneath.
"If there's a flu pandemic then handshaking might be something you want to think about or in a hospital with the spread of superbugs."
It is not the first time the argument has been raised. There have been calls in the Journal of the American Medical Association to ban handshakes from hospitals, external.
"There's a lot of inertia into changing this, a handshake is a badge of office and medics are trained to have a firm handshake to infuse patients with confidence, but you've got to ask is that appropriate behaviour," Dr Whitworth added.