Like all seafood, shrimp naturally contains bacterium that you must cook to destroy. And even after the shrimp is cooked, bacteria is still an issue. Left too long at room temperature, any bacteria that cooking did not destroy begins to multiply again. When this happens, cooked shrimp stays good for only a short period of time before bacteria growth rises to levels that can make you sick if you eat it.
Shrimp stays good for only two hours after it's cooked and served. On the serving tray in temperatures of 40 degrees Fahrenheit or above, the cooked shrimp begins to fall victim to dangerous bacterial growth when two hours have passed. After this time, the cooked shrimp cannot be refrigerated, frozen or eaten; you must throw it away. In temperatures of 90 F and above, the cooked shrimp lasts only an hour.
Refrigeration increases the shelf life of cooked shrimp. Refrigerated within two hours of cooking -- one hour if the temperatures break the 90 F mark -- cooked shrimp keeps for three to four days. Place the cooked shrimp in a plastic storage bag or wrap it tightly in plastic wrap or aluminum foil before popping it in the refrigerator. Plastic storage containers also keep cooked shrimp fresh in the refrigerator, provided the lid is secured tightly.
Freezing is the alternative to refrigeration if you think you may not get around to eating the cooked shrimp within three to four days. Freezing keeps the cooked shrimp safe to eat for an indefinite period of time, but safe does not always mean palatable. Although freezing renders bacteria inactive, making safety a non-issue, quality begins to diminish after six months. When this happens, the taste and texture of the cooked shrimp begin to change.
Thawing Cooked Shrimp
Safe thawing ensures that you do not become sick from inactive bacteria that become active again when the internal temperature of the cooked shrimp rises above 40 F. Transfer cooked shrimp from freezer to refrigerator the night before, giving the cooked shrimp time to thaw before eating. In a pinch, thaw in the microwave, reheating immediately afterward. An internal temperature of 145 F, measured with a meat thermometer, renders the cooked shrimp safe enough to eat.