An inspection warrant shall be effective for the time specified therein, for a period of not more than seven days, unless extended or renewed by the judicial officer who signed and issued the original warrant. The judicial officer may extend or renew the inspection warrant upon application for extension or renewal setting forth the results which have been obtained or a reasonable explanation of the failure to obtain such results. The extension or renewal period of the warrant shall not exceed seven days. The warrant shall be executed and returned to the clerk of the circuit court of the city or county wherein the inspection was made. The return shall list any samples taken pursuant to the warrant. After the expiration of such time, the warrant, unless executed, shall be void.