Electron Microscopes and their calculations were but estimates. The calculations may be right and perhaps not. I would suspect they are looking at the molecular bonding forces in the cell membrane of the bacterium and what is needed to force it apart. This is really rocket science with "wag" also known as "wild ass guess." I hope they are right.
Exactly. An SEM cannot measure a “force.” If they can, it is news to me. Note the specifics are never mentioned but that was not the intent of the piece. A journal article will most likely do that, but even then they are very wanting.