It’s permissible to re-torque if necessary; however, whether you need to re-torque a clamp or not is specific to the particular connection. Often the need to re-torque is caused by a poor-quality clamp that had to be over-torqued to get it to seal in the first place, and which later relaxed during a thermal cycle. The need to re-torque a number of times could also be the result of using poor-quality gaskets or using the clamp for too long.
A more reliable solution is to choose a higher-quality clamp which will keep you from having to over-torque during installation. In this case, subsequent re-torque may not be required at all, contributing to a more sterile process.
Advanced Couplings clamps are sized to minimise the variance between the clamp segments, reducing the need for re-torquing and freeing maintenance staff for other work.
Since the clamps and ferrules are not pre-stressed, there will be a tendency for them to relax over time. If your process involves thermal cycling testing of pipes and their hygienic clamp connections, then a re-torque may be needed.