Wikipedia
A muḥtasib (Arabic: محتسب) was a supervisor of bazaars and trade in the medieval Islamic countries. His duty was to ensure that public business was conducted in accordance with the law of sharia.
In the reign of the Sultan Barqūq, for example, the duties of the muḥtasib of Cairo included "the regulation of weights, money, prices, public morals, and the cleanliness of public places, as well as the supervision of schools, instruction, teachers, and students, and attention to public baths, general public safety, and the circulation of traffic." The muhtasib or muhtesip was authorized to audit the businesses if they were selling their products at the price limits set by the government. In addition, craftsmen and builders were usually responsible to the muhtasib for the standards of their craft. The muhtasib also inspected if the food sold was safe and the measuring equipment was accurate.
"The Muḥtasib also inspected public eating houses. He could order pots and pans to be re-tinned or replaced; all vessels and their contents had to be kept covered against flies and insects... The Muḥtasib was also expected to keep a close check on all doctors, surgeons, blood-letters and apothecaries."
A muḥtasib often relied on manuals called ḥisba, which were written specifically for instruction and guidance in his duties; they contained practical advice on management of the marketplace, as well as other things a muhtasib needed to know — for example, manufacturing and construction standards.