Can drunken shrimp, drunken crab, sashimi, white wine and aged vinegar kill parasites in raw food?

Review expert: Wu Xinsheng, deputy chief physician of gastroenterology department

The hot weather makes people love raw pickled products. Drunken shrimp, sashimi, raw pickled crabs... the so-called must-eat summer delicacies make people salivate, and the raw pickled recipes circulating on the Internet are also popular. While everyone is enjoying the crispy taste of raw food, invisible dangers are also approaching.

Recently, there was a piece of news like this: A man who had a history of eating raw fish for more than 30 years was rushed to the hospital because he had repeated fevers after eating raw pickled shrimp and blood clams. After examination, the surprising result appeared. In addition to liver and gallbladder lesions, the doctor also found liver flukes in his body.

Source｜News screenshot

What is liver fluke

Liver fluke, also known as Clonorchis sinensis , is difficult to identify with the naked eye. Its average size is only 0.138×0.15mm, so it is difficult for people to directly find it when eating it in daily life. Outside the metacercariae of liver fluke, there are two layers of cyst walls like protective shells.

The eggs of liver fluke mainly survive in fish ponds. Freshwater fish are the favorite hosts of liver fluke. Liver flukes are often concentrated on the back and tail of fish. When people eat raw freshwater fish or uncooked fish or shrimp meat carrying liver fluke eggs, about a month later, melon seed-shaped adult worms can be found in your liver bile duct, and the number can even reach an astonishing tens of thousands.

Source: Guangdong TV News

The liver fluke that parasitizes the human liver has a very abnormal reproductive capacity. It can reproduce as a hermaphrodite, producing 1,600 to 4,000 eggs a day, and more than 1 million eggs a year. The numbers are terrifying. But what is even more terrifying is that the liver fluke has a long lifespan. It can live in the body for 20 to 30 years and damage your liver without you noticing.

The origin of Clonorchis sinensis adults and eggs | Baidu Encyclopedia

The dangers of liver fluke disease

Due to the strong parasitic ability of liver flukes, the incidence of liver fluke disease (clonorchiasis, commonly known as fish worm disease) is not low. In Guangzhou, where the phenomenon of eating raw fish fillets is very common, the infection rate is about 10%. Liver fluke disease is a chronic disease. The degree of liver and bile duct lesions and the severity of clinical symptoms of the infected person depend on the number and duration of infection with the worm.

As a parasitic disease that seriously endangers health, when adult liver flukes parasitize in the hepatobiliary ducts of humans (or cats and dogs), a series of disease symptoms will be triggered. First, there will be hypersensitivity and inflammatory reactions in the bile duct lining and around the bile duct, with symptoms such as local bile duct dilatation, bile duct epithelial hyperplasia, and destruction of the bile duct epithelium and submucosal blood vessels. Cholangitis, cholecystitis, or obstructive jaundice may also occur. At the same time, the presence of liver flukes can also block the bile duct and thicken the bile duct wall. Worm fragments, eggs, and exfoliated cells of the bile duct epithelium can easily form bile duct stones and even lead to liver cancer.

Source of liver flukes removed from the liver | News photo

When the liver fluke infection is severe, it may be accompanied by serious consequences such as fibrosis, hepatocyte degeneration, and biliary cirrhosis. In addition to liver and gallbladder diseases, adult schistosomiasis can also parasitize in the pancreatic duct, causing pancreatitis and pancreatitis. For children and adolescents, the danger of liver fluke disease cannot be underestimated. The clinical manifestations are more severe and the mortality rate is higher.

Do you think this will kill the liver fluke?

In the folk, people have their own opinions on how to handle raw fish. Some people think that high concentration of liquor can kill bacteria, and some people think that parasites are afraid of acid, so adding more vinegar can kill them. Others think that garlic and mustard can kill bacteria, so there is no need to worry if you mix them together. In fact, these opinions and practices are not advisable and ineffective. Liver flukes have two layers of cyst walls like protective shells, which make them not afraid of being soaked in liquor and aged vinegar. Studies have shown that the metacercariae of liver flukes can survive for 5 hours in soy sauce and 2 hours in vinegar before dying.

Source: unsplash

Therefore, it is not feasible to kill liver flukes by seasoning. The parasites must be heated continuously at 60℃ for more than one minute to kill them. Some people are lucky enough to scald the fish fillets in boiling water in order to preserve the sweet taste of fish meat. However, liver flukes are not that fragile. Insufficient temperature or too short a time will not kill them. Therefore, foods such as sashimi, sashimi porridge, and fish fillet hot pot also have the risk of infection when they are not cooked properly. What is even more unfair is that even if you don’t eat sashimi, you may be infected by the chopsticks of the people eating with you.

Source | Sohu

Prevention and treatment of liver fluke disease

When studying liver fluke disease, researchers found that the disease continued to be prevalent in South China and Northeast China. The most direct reason was the habit of eating raw freshwater fish in these areas. Therefore, the way for individuals to nip liver fluke disease in the bud was to cook food at high temperatures.

Source | pixabay

In the larger environment, if we want to prevent and control liver flukes from the source, it is extremely important to create a sanitary environment. The more recommended practice nowadays is for the government to organize the creation of harmless sanitary toilets to prevent feces from entering the water, ponds, and seas directly, thereby preventing water pollution.

For those who like to eat raw fish, it is important to pay attention to physical examinations, such as using CT and B-ultrasound to check whether there are lesions in the liver and gallbladder, and using fecal direct smears to check whether there are liver fluke eggs. If liver flukes are detected, relevant treatment should be carried out in a timely manner depending on the degree of infection.

Source | pixabay

In short, eating raw fish is unsafe and liver fluke disease is very harmful. The simplest way is to refuse to eat freshwater raw fish and try to separate raw and cooked food when using kitchen utensils. If you really want to eat raw fish, try to buy less harmful deep-sea fish through trustworthy channels.