HCP is a patented process whereby live oysters are placed in warm water for a certain time period and then immediately dipped in cold water to stop the cooking process. These oysters are packed for the half-shell market or sent for further processing as a shucked product.
HHP is also a patented process that subjects oysters to high pressures (35,000 to 40,000 pounds per square inch) for 3 to 5 minutes to kill spoilage bacteria and reduce microorganisms including Vibrio to non-detectable levels.
IQF involves rapid freezing of half-shell oysters on trays, then adding a thin glaze of ice to seal in the natural juices before storing them frozen.
Cobalt-60 irradiation (C-60) is the traditional means used to irradiate foods. The gamma-ray from the cobalt isotope is very penetrating through food packages and products. There is no residual radioactivity.
Commercial Oyster Postharvest Processing Processing Systems
List of commercial oyster postharvest processing systems at http://www.issc.org/post-harvest-processors.