(1) In the above case, such local standards would be the first requirements to ensure compliance with. IIRC, Saudi Arabia publishes quite detailed requirements for food manufacturing establishments but I'm unaware of equivalent documentation for restaurants ?.
The reason I asked is that, afaik, and just as an example, US retail food handling facilities implement procedures based on the US Retail Food Code, ie -
US Food Code,2013.pdf 6.92MB
(probably not latest edition)
(2) In a procedural sense, you might find this website of interest -
(3) With respect to generic Food Standards, these two, iso-based, standards are intended for "quality" and "safety" respectively (there are many other safety standards) -
Numerous texts / books contain practical implementation examples of (1,2), eg -