When you open the package of raw or cooked shrimp, you will notice an ammonia-like smell, which indicates that the shrimp has gone bad. It's normal for fresh shrimp to have a faint scent. It is crucial to consider the texture. The shrimp' texture should be firm and snappy, not rubbery or mushy. If this is not the case, the shrimp should be removed. Spoilage is evident when mould appears on cooked or raw shrimp in the shape of black patches, which indicates that the shrimps have gone bad.