Hard clams should be kept refrigerated at about 40 degrees F in a moist environment. By law, every container of hard clams must have a tag indicating that it was harvested from certified waters and handled by licensed dealers. Shellfish samples are regularly collected from harvest areas, certified shellfish dealers and retailers for bacteriological examination by state environmental regulators and health officers.
Also, state and federal inspectors routinely check the shipping containers of shellfish to be sure that wholesalers are providing proper identification tags for the shellfish. Shellfish tags should be retained on the bag or box of shellfish until they are used and the tag should be retained on file for 90 days. This is a protection for the foodservice operator since it is proof that the clams were purchased from an approved dealer. This process becomes even more controlled when the hard clams are aquacultured since the product is under constatnt monitoring and scrutiny by the grower.
When selecting clams, discard those whose open shells will not close when touched or prodded.