If the cooked crab is wrapped in plastic wrap and put into the refrigerator freezer, it can be kept for about 6 to 8 hours, and if it is put into the refrigerator freezer, it can be kept for about two days. What's more, crab is a food containing more histaminic acid, overnight leftover crab species histidine in the role of certain vitamins, will be decomposed into histamine, back to the pot when heated, although it can kill pathogenic microorganisms, but can not destroy the toxin, if you eat overnight crab, may lead to histidine poisoning.