Alms Tax: Asking for Zakat by an Appointed Collector
Practical Laws of Islam as per the teachings of Ayatullah Sistani
Ruling 1883
A person who has been appointed by a fully qualified jurist (al‑ḥākim al‑sharʿī) to collect zakat can ask for it at the time when grain is threshed and separated from the chaff, and when dates and grapes become dry. If the owner does not give it and the thing on which zakat has become obligatory perishes, the owner must give compensation for it.
-Ayatullah Sistani, Practical Laws of Islam, Alms Tax (Zakat)