7 Pa. Code § 1.573
When any article or livestock is retained an authorized representative of the Department shall give oral notification to the owner of the article or livestock retained if he can be ascertained and notified and, if not, to his agent or the immediate custodian of the article or livestock, and promptly furnish the person so notified in writing with a Notice of Retention. Within 48 hours after the retention of any article or livestock, an authorized representative of the Department shall, if the retention is to continue, give written notification of Notice of Retention to the owner of the article or livestock retained, or if such owner cannot be ascertained and notified within such period of time, furnish such notice to his agent, or the carrier or other person having custody of the article or livestock detained. The written notification shall be served by either delivering the notification to such owner or his agent, or to such other person, or by certifying and mailing the notification, addressed to such owner, agent or other person at his last known residence or principal office or place of business.
7 Pa. Code § 1.573