The person signing and issuing the certificate shall be one of the following:
The inspector who performed the inspection.
Another employee of the Inspection Service who has been given power of attorney by the inspector who performed the inspection and authorized by the Administrator to affix the inspector's signature to an inspection certificate.
An inspector designated as the “inspector in charge,” when the certificate represents composite inspection of several persons.
A certificate of loading shall be issued and signed by the inspector or licensed sampler authorized to check the loading of a specific lot of processed products: Provided, That, another employee of the inspection service may sign such certificate of loading covering any processed product checkloaded by an inspector or licensed sampler when given power of attorney by such inspector or licensed sampler and authorized by the Administrator to affix the inspector's or licensed sampler's signature to a certificate of loading which has been prepared in accordance with the facts set forth in the notes made by the inspector or licensed sampler in connection with the checkloading of a specific lot of processed products.