(a) Properly certified foreign animal casings arriving in the United States at a seaboard or border port where an APHIS inspector is stationed shall be released for entry by the inspector at the seaboard or border port.

(b) Properly certified foreign animal casings arriving in the United States at a seaboard or border port where no APHIS inspector is stationed, which are destined to a point in the United States where an APHIS inspector is stationed, shall be shipped in United States Customs custody to destination for release.

(c) Properly certified foreign animal casing arriving in the United States at a seaboard or border port where no APHIS inspector is stationed, which are destined to a point in the United States where no APHIS inspector is stationed, shall be transported in United States Customs custody to the nearest point where an APHIS inspector is stationed for release at that point.

(d) Properly certified foreign animal casings forming a part of a foreign meat consignment routed through a border port to an interior point in the United States shall be transported to destination as though the entire consignment consisted of meat. In such cases the APHIS inspector who inspects the meat at destination shall supervise the release of the casings.