More than 76 million people get food poisoning every year, and eating spoiled shellfish is one of the more common causes. Symptoms of food poisoning can include severe vomiting and diarrhea. That's not exactly the way you want to follow up your seafood meal. Shrimp is a type of shellfish used in many recipes, and it's vital that you spot the signs of spoiled shrimp in order to keep yourself and those you cook for healthy.
Spoilage vs. Pathogens
Spoiled food isn't the same as the food pathogens that can cause things like E. coli or noro virus. Food spoilage happens when food gets too old. You can usually smell, see and taste the spoilage. If you don't eat fresh shrimp soon enough, you'll notice those changes that indicate spoilage.
Food pathogens can contaminate shrimp at any point even if they're not old or spoiled. You usually can't detect the food pathogens as they don't cause changes in appearance, smell or taste. Pathogens might include bacteria, viruses and parasites, and they can cause different types of illnesses, sometimes severe.
Spoiled Shrimp Smell
Using your senses is the best way to figure out whether or no the shrimp is still good. Smell the shrimp before you purchase it. Since you can't smell shrimp through plastic packaging, it's safer to buy fresh shrimp over the counter in a supermarket or from a fishmonger.
Fresh shrimp should have little to no odor and smell slightly salty, like sea water. If the shrimp smells like ammonia, or if it generally smells slightly "off," don't purchase it. The ammonia or "off" smell is caused by the growth of bacteria in the spoiled shrimp, which is likely to cause food poisoning if eaten.
Fresh shrimp have firm bodies that are still attached to the shell. They should also have clear and clean shells with a pearl-like color. If the bodies appear loose within the shell or if there are black spots on the shell, it's likely that the flesh has started to decompose inside.
Also ensure that the shells are firm and glossy. If the shells are broken and slippery or slimy, the shrimp is likely to be spoiled and shouldn't be purchased. Again, it's easier to check this by looking directly at fresh, loose shrimp rather than prepackaged shrimp.
Make sure that the shrimp aren't discolored on the heads and on the shells. If you're buying raw shrimp, they should be white and slightly transparent. If you are buying cooked shrimp, they should be pink. Bad shrimp look discolored, and that discoloration might indicate that the flesh is spoiled.
Also, look to see if the shells appear yellow or gritty. This may indicate that a chemical such as sodium bi-sulfate has been used to bleach the shells. The chemical may have been used to disguise the fact that the shrimp are old.
Buying shrimp with their heads still on can help you to identify whether or not they're spoiled. The eyes should be prominent and shiny. If they look shrunken or dried out or are missing altogether, you should be wary of how fresh the shrimp are. To be on the safe side, purchase your shrimp elsewhere.
Frozen Shrimp Appearance
Issues with frozen shrimp include freezer burns and thawing and refreezing. Frost or ice crystals in the packaging or on the shrimp can indicate either of these issues. Freezer burn on shrimp happens when the shrimp is stored for a long time. Tears in the bag can also indicate an issue.
You can generally still eat freezer burned shrimp. Spending too much time in the freezer can change the flavor and texture of the shrimp. Unless you notice an off smell or other signs of spoiled shrimp, the seafood should be safe to eat.
- Help With Cooking:Help With Cooking: Choosing and Buying Fresh Prawns and Shrimps
- Food Info: Scombrotoxin
- Wild American Shrimp: Shrimp Tips
- U.S. Food and Drug Administration: Selecting and Serving Fresh and Frozen Seafood Safety
- Food Gear: Freezer Burnt Shrimp: Know How to Make Them Safe to Eat
- Michigan State University: Food Spoilage and Food Pathogens, What's the Difference?