Why Tuna Is Frozen Right After Catching

Why is most tuna around the world frozen immediately after being caught? Tuna is a highly sensitive fish that can spoil quickly, even when stored on regular ice. That is why many fishing vessels use ultra-low temperature freezing to preserve its quality. This rapid freezing process helps prevent large ice crystals from forming inside the meat, keeping the texture and flavor closer to fresh tuna. Immediate cooling also slows the conversion of histidine in tuna muscles into histamine, a harmful substance that can cause food poisoning. Fresh tuna transport is rare and usually reserved for premium sushi-grade fish because it requires fast and expensive air shipping.