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Summer is here, and it is a great season to eat raw and pickled foods.In coastal areas such as Chaoshan and Shunde, a traditional delicacy called "raw pickled food" is very popular among locals. From fresh shrimps and crabs to plump shellfish, these seafoods can present a unique taste and flavor after simple pickling.

In the past two years, with the rise of short video platforms, raw pickled food has set off a craze, making more people interested in this unique delicacy.

However, behind this craze, its safety issues have also attracted public attention: Is raw marinated seafood safe? Can we eat it?

Raw pickling, that is, raw food pickling. The method is to pickle fresh ingredients, such as seafood or meat, with white wine, soy sauce, garlic, chili and other seasonings. Some people will also add lemon juice or mustard sauce according to personal taste, and then eat it directly or cook it with other foods.

Because raw pickled foods are usually stored in the refrigerator, they taste cool and are especially refreshing. At the same time, their sour and spicy taste is also appetizing and can increase appetite on hot summer days, so they are very suitable for consumption in summer.

Many people are keen on eating raw pickled food because it can make food more "fresh". Once many people try it, they will be deeply attracted by the taste, as if addicted, so it is called "human poison". It is said that there is only a difference between eating raw pickled food 0 times and eating it countless times.

Although the raw pickling method can preserve the original flavor of the ingredients, it also brings certain safety issues.

Image source: Weibo screenshot

Some people may argue that raw pickles contain white wine, sometimes spicy mustard, and salty condiments, which can kill bacteria.

However, these cannot completely kill germs and parasites.

Take the most commonly used liquor as an example. Although liquor is added during the production of raw pickles, the alcohol content of liquor varies greatly. Even for high-proof liquor, most are only over 50 degrees, which is still a long way from the alcohol concentration that can kill bacteria (70% ~ 75%).

In addition, even 75% medical disinfectant alcohol cannot kill all germs. For example, Norovirus and Hepatitis B virus have a certain resistance to 75% alcohol.

Moreover, seafood contains not only bacteria and viruses, but also parasites, which alcohol cannot protect against.

From 2001 to 2004, the Ministry of Health conducted the second national survey on the status of major parasitic diseases in 27 provinces and cities. One of the parasites with the highest infection rate in my country, Clonorchis sinensis (liver fluke), often appears in drunken shrimp and freshwater fish. During the national survey, it was found that the average infection rate in China was 2.4%, while in Guangdong Province, where people love to eat raw and pickled food, the infection rate of Clonorchis sinensis was as high as 16.42%.

Image source: "National Survey Report on the Current Status of Important Human Parasitic Diseases"

The safety of raw pickled foods has always been controversial. Although some raw pickled foods are strictly processed and pickled to kill some bacteria and parasites, their safety cannot be fully guaranteed.

You may say, I have been eating it since I was a child and there is no problem with it?

This is because the parasites may survive or cause health problems for decades.Taking Clonorchis sinensis (liver fluke), the most prominent parasite in freshwater fish, as an example, more than 100 species of freshwater fish can be infected with liver fluke, mainly carp species such as grass carp, silver carp or bighead carp.

Image source: Centers for Disease Control and Prevention

The average survival time of liver flukes in the human body is usually 15 to 25 years. Infection with liver flukes does not necessarily cause symptoms. In the case of mild infection, there may be no symptoms or only mild manifestations, which may be similar to other common diseases and are therefore easily overlooked.

However, if infected with more liver flukes, it can cause problems such as loss of appetite, diarrhea, and fever. Because it mainly parasitizes in the bile duct of adults, it can also cause bile obstruction, cirrhosis, and even jaundice. Some people may also develop bile duct cancer. Therefore, the International Agency for Research on Cancer (IARC) defined Clonorchis sinensis as a type of carcinogenic parasitic infection in 2009.

To this end, the Chinese Center for Disease Control and Prevention calls for:In areas where people have the habit of eating raw fish and shrimp, we must change customs and eliminate bad eating habits. We must not eat raw fish, raw shrimp, or uncooked fish and shrimp.

Some friends believe that freshwater fish are prone to parasites. Since marine fish live in high-salt seawater for a long time, do they not have parasite problems?

In fact, there are thousands of parasites in seawater. The most common parasite in marine fish is Anisakis, which can infect pomfret, cod, cuttlefish, hairtail, yellow croaker, etc.

Symptoms of infection with this parasite may appear within a few hours or delayed until about a week later. Symptoms may range from mild gastrointestinal discomfort to severe abdominal pain, persistent diarrhea, vomiting, stomach ulcers, and in extreme cases, stomach perforation.

Image source: ScienceNews

In addition to parasitic infections, raw pickled foods may also contain potential hazards of bacteria and viruses. Since raw pickled foods are not cooked at high temperatures, the bacteria and viruses in them may not be completely killed, thus posing a threat to human health. The World Health Organization (WHO) points out that raw or semi-raw foods that have not been fully heated may carry bacteria and cause infection.

Every summer, due to the popularity of roadside food stalls and the rise of raw and pickled delicacies, some friends who love to eat snails and raw and pickled snails increase their consumption of aquatic products.

Raw, marinated or undercooked seafood may contain pathogenic bacteria such as Vibrio parahaemolyticus, Vibrio vulnificus, and Salmonella. Once these bacteria enter the human body, they may cause symptoms such as diarrhea, abdominal distension, vomiting, nausea, and even severe bacteremia and death.

The more common foodborne viruses are norovirus and hepatitis A virus. Shellfish and other seafood are easily contaminated by water. As mentioned earlier, strong liquor can basically not kill these two viruses.

Therefore, in the summer, the rate of medical treatment for diseases caused by eating seafood among residents in coastal areas will increase significantly.

Image source: Analysis of foodborne disease surveillance data from 2019 to 2021 in a tertiary general hospital in Shandong Province

According to the patient data of a tertiary hospital in Rizhao City, Shandong Province, the number of patients with foodborne diseases is the highest from June to September, and the top three causes are Norovirus (9.53%), Vibrio parahaemolyticus (8.54%) and Salmonella (1.91%). Most of these are related to seafood.

Image source: Analysis of foodborne disease surveillance data from a tertiary general hospital in Shandong Province from 2019 to 2021

Shellfish and freshwater fish contain thiaminase, which breaks down vitamin B in food.₁。

Frequent consumption of raw pickles may lead to₁A deficiency of vitamin C can lead to "beriberi". The beriberi here is completely different from the athlete's foot we commonly know (athlete's foot is tinea pedis, the most common superficial fungal pathogen caused by pathogenic fungi infecting the feet). People with beriberi mainly show symptoms of the nervous system and circulatory system, such as apathy, mental confusion, slow reaction, and even limb sensory and movement disorders. Some people also have heart health problems.

In addition, the protein in raw aquatic products does not denature after heating, and the structure of the protein is not conducive to human absorption, increasing the burden of digestion.

Therefore, raw pickling is not only unsafe, but also affects long-term health.

To ensure the safety of eating seafood, we should take some precautions.

Formal channels and freshness are both indispensable.

Seafood in supermarkets and large markets is generally inspected regularly, so its safety is more reliable.

In addition, the freshness of seafood not only affects the taste, but also determines its safety. Some green-skinned red fish that are not fresh will produce toxic histamine, a biogenic amine that can cause poisoning reactions such as dizziness, pain, vomiting, and other symptoms when ingested in excess.

Whether it is a parasite, bacteria or virus, the survival rate can be greatly reduced after being heated at high temperature.

The World Health Organization mentioned in the "Five Keys to Food Safety":Cook food thoroughly, especially meat, poultry, eggs and seafood. Proper cooking kills almost all microorganisms. Studies have shown that cooking food to 70°C can help ensure it is safe to eat.

Therefore, when making it, make sure it is fully heated. If the cut is thicker or the ingredients are not easy to cook, heat and cook it for a while longer.

Although the pace of life is fast, we should not only pursue the stimulation of taste buds, but also pay attention to the safety and health of food. Raw marinated seafood, this delicious food that makes people yearn for, has hidden uncertainties, which force us to re-examine it. Although its flavor is irresistible, safety is the first priority on our table.

Source: Science Popularization China