Shucked shellfish shall be packed and shipped either in single-service containers made of clean impervious materials or in properly designed, returnable containers* which have received adequate cleansing and bactericidal treatment. All containers shall be stored in a manner that will protect them from contamination. Containers holding one gallon or more must be positively sealed or so sealed that tampering with the container can easily be detected. Each can, container, or package shall bear the name of the shipper, certificate number of the shucking, packing, or repacking plant, and date packed. The date may be in code if the code is registered with the State Department of Public Health.