Continuous inspection shall not be provided under this part at any plant for the processing of any egg products which are not intended for use as human food, but such articles prior to their offer for sale or transportation in commerce shall be denatured or decharacterized unless shipped under seal as authorized in §§ 590.504(c), and identified as prescribed by the regulations in this part to prevent their use for human food. Periodic inspections shall be made of such operations and records to assure compliance with the Act and the regulations in this part.