By Harold McGee
Irradiation preserves food by way of high-energy particles that damage the DNA and proteins of spoilage microbes. Pilot studies have found that irradiation can extend the refrigerated shelf life of fresh fish by as much as two weeks. However, the initial deterioration of fish quality is caused by the action of fish enzymes and oxygen, and this action proceeds despite irradiation. Also, irradiation can produce off-flavors of its own. It’s unclear whether irradiation will become an important means of preservation for fish.