The undisputed king of late-night summer snacks is none other than crayfish, but there are countless rumors surrounding them. The real name of the crayfish is "Procambarus clarkii," and it is a genuine freshwater shrimp. It is related to lobsters, and taxonomically, they both belong to the order "Decapoda." Lobsters belong to the families Palinuridae, Astacidae, or Cambaridae, while the crayfish we eat belongs to the family Cambaridae, so crayfish are not insects.
Are heavy metal levels in crayfish hundreds of times over the standard?
Crayfish can survive in severely polluted environments. However, most of the heavy metals they ingest are transferred to their shells. As they grow and molt, these heavy metal toxins are expelled from their bodies. Therefore, the heavy metal content in the meat is not necessarily excessive. Some research data indicate that, besides the shells, heavy metals in crayfish are mostly concentrated in the gills and internal organs, which are mainly located in the head. The tail, which we eat, contains very little heavy metal, so the possibility of poisoning is low. Regulatory authorities have not found any issues with excessive pollutants in crayfish during their routine inspections.
How to choose healthy crayfish in the summer?
1. Identify cooked crayfish by color
When cooking crayfish at home, be sure to cook them thoroughly at high heat. You can judge if they are cooked by observing whether the cross-section of the shrimp meat has a consistent color.
2. Don't eat the head, as it contains more toxins
"The head of the crayfish must never be eaten." The head is the part of the crayfish that absorbs and processes the most toxins and is also where pathogens and parasites are most likely to accumulate.
In addition, eat crayfish in moderation. Do not consume too many at once, as shrimp is a high-protein food, and some people with allergies may have allergic reactions to crayfish, such as red spots or hives on the skin. It is best not to eat crayfish if you are allergic. Crayfish are also a seafood product high in purines, so people with gout should not eat them.
3. Dead and spoiled crayfish cannot be eaten
Shrimp contain histidine, which is the main component that gives them their delicious flavor. However, once the shrimp dies, histidine is decomposed by bacteria into histamine, which is harmful to the human body. Furthermore, the intestines of shrimp often contain pathogenic bacteria and toxic substances, and the body easily spoils after death. Especially as the time since death increases, more toxins accumulate in the shrimp, and eating them can lead to poisoning.
4. Cook and eat them fresh, and make sure they are thoroughly cooked
This is because the bodies of shrimp often contain metacercariae of lung flukes and Vibrio parahaemolyticus. Eating undercooked shrimp can easily lead to a lung fluke infection and cause gastrointestinal poisoning. Freshly cooked shrimp should not be stored; if eaten a second time, it must be reheated.
Tips for cleaning crayfish
1. Vinegar + Salt
Place your carefully selected crayfish in a basin of water mixed with vinegar and salt for 15 minutes. This forces the crayfish to expel dirt from their gills. Then, rinse them three times with clean water, and you're done.
2. Automatic Cleaning
The most difficult part to clean on a crayfish is its abdomen and claws. After buying the crayfish, don't rush to eat them. Place them in a basin, add a little salt, and then add enough water to cover them. Soak for 24 hours. After a day of crawling around the basin, most of the dirt in their abdomens will have been washed out. At the same time, due to the effect of the saltwater, the crayfish will also have expelled foreign substances from their bodies, achieving two goals with one effort.