Is it permissible to deposit Zakat al-Mal into a charitable organization's Zakat account due to my trust in its reaching those in need?

It is originally permissible to deposit zakat (definition) in the special zakat account of charitable organizations, so that they may deliver it to those who are eligible. This falls under the category of deputizing someone to disburse zakat, which is permissible. It is stated in the Kuwaiti Encyclopedia of Fiqh: "It is permissible for the one paying zakat to deputize another to pay his zakat, whether by delivering it to the Imam or his deputy, or by paying it to the eligible recipient." It is necessary to seek trustworthy institutions and verify that they indeed give zakat to those who are eligible.