A shipowner or master applies to an authorized officer at a UK port for a ship sanitation control certificate. Under The Public Health (Ships) Regulations, what must the authorized officer do?

Then, if satisfied that the ship is exempt from control measures, he must issue a Ship Sanitation Control Certificate. When (alternatively) any necessary control measures have been completed to his satisfaction, he must issue a Ship Sanitation Control Certificate and note on it the control measures taken. (Reg. 18A)