Very few jellyfish are actually edible. The scyphozoan jellyfish (about 12 of the 85 species or so) are one of the more popular jellyfish often harvested for food. Most of the harvesting takes place in locations such as Southeast Asia. Fisheries have also begun harvesting the American cannonball jellyfish located along the southern Atlantic coast of the United States and in the Gulf of Mexico to export to Asia because they are larger with more rigid bodies and their toxins are harmless to humans, making them a favored meal when compared to other types of jellyfish.
Traditional processing methods are carried out by a “jellyfish master” and involve a multi-phase procedure that takes 20-40 days. During this procedure the gonads and mucous membranes are removed, and then the umbrella and oral arms are treated with a mixture of table salt and alum then compressed. Processing reduces liquefaction, odor, and the growth of spoilage organisms and also makes the fish drier and more acidic which in turn produces a crunchy, crisp texture.
Jellyfish that are prepared this way retain 7-10% of their original weight the processed product contains approximately 94% water and 6% protein. Freshly processed jellyfish often has a white creamy color and will turn yellow or brown during prolonged storage. Despite their high water content, these creatures are actually quite nutritious. They are almost completely free of cholesterol, calories, carbohydrates and saturated fats.
In China, jellyfish are processed by being desalted first by being soaked in water overnight and then eaten raw or cooked. The jellyfish dish is often served shredded up with a dressing of oil, soy sauce, vinegar, and sugar. Or it is sometimes served as a salad with vegetables. In Japan, cured jellyfish are rinsed and then cut into strips and served along with vinegar as an appetizer. Desalted, ready to eat products are also another popular choice available for consumption. Some individuals prefer to cook jellyfish and then let it sit in cold water for about 8 hours, blanch it and add some seasonings to it. It is very important to keep cooked and raw jellyfish apart from each other. Even though they mostly contain water, they are still able to hold the same type of bacteria as other meats.