1. Look at the color: There are two types of frozen shrimp, one is red shrimp. Red shrimp is shrimp that has been cooked and then frozen. For this kind, look at the color of the shrimp head. The shrimp heads are very bright and not black, so they are good shrimps. And if it turns black, it is stale. Red shrimps are cooked and have black heads. They are dead and frozen. This kind of shrimp is not allowed. Dead shrimps must not be eaten. As soon as the lobsters die, the bacteria will decompose immediately. People who eat them will be easily poisoned and suffer from diarrhea. Moreover, lobster contains a large amount of histidine. When the lobster dies, these histidines will quickly turn into toxic substances, which can easily cause food poisoning after human consumption. Only crayfish that have died after being chilled can be eaten. It's not okay to die before freezing. Most of the frozen crayfish are frozen directly when the lobster is alive. Although this kind of crayfish is dead, most of it has been frozen due to the low temperature, which will inhibit the growth of fungi and delay protein spoilage. After thawing, cook it as soon as possible. Edible. The second type is green shrimp. For this. Look at the color of the shrimp shell. Relatively white, bluish-white is the best, not red, red is stale. Black is also bad. The reason why the red shrimp in frozen shrimp can be red is that it has been cooked beforehand. After the shrimp is cooked, it turns red due to the astaxanthin in the body. The shrimps are already cooked and frozen for sale. However, you have to cook it after you buy it home. Even if it is cooked, you cannot eat it directly

2. Look at the appearance: Whether it is red shrimp or green shrimp, you can use this method to quickly identify it, that is, look at the head of the shrimp. Whether it has fallen off or not? If the whole shrimp is relatively complete and the head and tail are closely connected to the body, it means the shrimp is relatively fresh. If the head of the shrimp has fallen off, the head and body, the shell and the meat are loosely connected, and the head and tail are easy to fall off or separate, they are not fresh.