Well, I shouldn't be telling you this, but obviously before turning the "sewer mud" into meat, it undergoes processes which kill the bacteria and dangerous viruses in it, turning it harmless enough, minus the disgusting factor.
Jokes aside, this IS the future. Development in nano-technology on the molecular level, if successful, could produce food from virtually anything, that would be identical and indistinguishable from the real thing, and that would be the least that could be possible with that kind of technology. Today engineering on the molecular level is science fiction, but be certain that if it could be achieved, anything would be possible.