The craze for eating crayfish in the summer has not yet passed, and soon it will be the Mid-Autumn Festival, when various seafood and river crabs will be served in large quantities. In terms of nutritional value, seafood and river crabs are indeed good choices. They are mostly low in fat and high in protein, and they also contain high levels of trace elements such as zinc, copper, selenium, and iodine. Many people have also heard that eating too much meat can increase the risk of heart disease, but seafood is beneficial for preventing cardiovascular and cerebrovascular diseases. So why is there a possibility of getting sick from eating seafood and river crabs?
I often feel that people's attitude towards food is unfair. For things they like to eat, they are tolerant of everything. No matter how troublesome, expensive, or dangerous it is, they still want to eat it. For things they don't like to eat, they can find any reason not to eat it. For example, people who are afraid of cholesterol will throw away egg yolks, but they will never throw away crab roe, even though crab roe also has a very high cholesterol content. In simple terms, it's because egg yolks are not as delicious as crab roe. People can't stop eating a delicious crab, and they even want to suck their fingers after eating it. "The smell of the fingers after touching the crab is still fragrant."
The Five Hidden Risks of Eating Seafood and River Crabs
Seafood and river crabs may be delicious, but they also come with a lot of troubles. These troubles can be roughly categorized into five types: pathogenic bacteria, parasites, various environmental pollutants such as heavy metals, allergies and intolerances, and the risk of promoting certain diseases.
First danger: Pathogenic microorganisms, including bacteria and viruses
According to the literature from both domestic and international sources, there are indeed many pathogenic bacteria and even highly pathogenic viruses found in crabs, shrimp, and shellfish. Take crabs for example, notorious pathogenic bacteria such as Vibrio parahaemolyticus, Vibrio cholerae, Listeria monocytogenes, and pathogenic Escherichia coli have all been reported in crabs. Especially, pathogenic Vibrio bacteria are particularly rampant in river and seafood, especially during the summer and autumn seasons. Once infected, the symptoms can range from vomiting and diarrhea to severe cases requiring emergency treatment.
Everyone's digestive system and immune system are different, so their reactions to pathogenic bacteria will also vary. If the stomach acid is strong enough to kill most of the microorganisms in food, then the likelihood of trouble is small. However, for those with weak digestion and insufficient stomach acid, if the cooking is not sufficient to thoroughly kill bacteria, or if they drink a lot of beverages or eat a lot of fruit during meals, diluting the stomach acid, then the pathogenic bacteria in the food can easily survive through the stomach and enter the intestines, causing bacterial food poisoning. Therefore, people with insufficient stomach acid should be especially cautious and eat less seafood and river crabs.
Second danger: Parasites
The trouble caused by various parasites in seafood cannot be ignored. For example, in shrimp, crabs, and snails, there may be various parasites such as roundworms, lung flukes, and blood flukes. Eating drunken snails or drunken crabs is very risky, and if they are not cooked thoroughly, the cysts of the parasites may not be destroyed. In the past few years, dozens of patients have suffered great pain due to eating undercooked snails and contracting roundworm infection. The parasites can even penetrate into the brain, and some patients have even been misdiagnosed as having brain tumors. We must not forget this painful lesson!
Therefore, these seafood delicacies must be cooked thoroughly and should never be eaten raw!
Third danger: Indecomposable environmental pollutants
The risks of bacteria, viruses, and parasites can be eliminated through cooking and heating; however, the pollution in seafood cannot be solved by heating. Since the aquaculture environment may have water pollution, seafood is immersed in water every day and will inevitably absorb pollutants. Moreover, the concentration of pollutants will increase tenfold or more as they move up the food chain. This is an external factor. On the other hand, shellfish and other seafood themselves have the characteristic of accumulating certain heavy metal elements. If the water is polluted at twice the concentration, it can become millions of times more polluted in seafood and river crabs. This is an internal factor.
According to data reported in China, the main pollutants that accumulate in seafood are heavy metals such as arsenic and cadmium. Measurements have shown that the arsenic content in seafood is much higher than that in meat, grains, and vegetables. For people who regularly eat seafood, it is the main source of arsenic in their diet. The Pearl River Delta region has higher levels of arsenic in seafood, and arsenic pollution in seafood in Taiwan is also serious (Li Xiaojun, et al., 2009). In 1988, the FAO/WHO recommended a provisional tolerable weekly intake (PTWI) of inorganic arsenic of 0.015 mg/kg body weight, and an acceptable daily intake (ADI) of 0.129 mg per person. If someone eats 1 kg of fish and seafood, calculated according to the national standard of arsenic content of 0.1 mg/kg fresh weight, plus the content in other foods, it is already close to the allowable intake. If seafood itself exceeds the standard for arsenic, then for people who love to eat seafood, exceeding the intake limit becomes a high probability event.
The cadmium limit for crustaceans such as crabs is 0.5 mg/kg, and exceeding this limit is quite common, with some cases even exceeding it by more than ten times. Some researchers believe that crabs have a stronger ability to accumulate cadmium pollution than shrimp, and cuttlefish and squid are also relatively high (Bi Shichuan, et al., 2009). The measurement data of seafood in the Pearl River Delta region also shows that cadmium exceeding the standard is relatively common in heavy metal pollution (Liu Fen, et al., 2009).
In addition, many reports have shown that seafood can accumulate other environmental pollutants besides toxic elements, such as the now banned highly residual pesticides such as DDT and dieldrin, and well-known indecomposable environmental pollutants such as dioxins and polychlorinated biphenyls. A domestic study found that if the residual level of dieldrin in vegetable fields is 0.2-3.6 μg/kg, the level in vegetables is only 0.3-9.8. In agricultural soils, the content is 0.4-1.2, and in grains, the content is 3.1-12.6. In surface water in the same region, the dieldrin content is 0.001-0.3 μg/kg, while the dieldrin content in seafood is as high as 38-46 (Xie Junqin, et al., 2003).
- It can be seen that seafood has a much higher ability to accumulate pesticide pollution than vegetables and grains. Whether the pesticide is applied by spraying, spreading, root irrigation, or mixing with soil, it will be washed into ponds, lakes, and rivers by rainwater, causing pesticide pollution in seafood. If one is really afraid of the accumulation of pesticide pollution, it is better to worry more about seafood and river crabs than vegetables and fruits.
Therefore, in order to avoid excessive intake of environmental pollutants, seafood and river crabs should be consumed in moderation and not eaten in excess. If we follow the recommendations of the Chinese Nutrition Society and eat about 75 grams per day (without shells or thorns, only the meat), it will not cause protein overload, and the intake of environmental pollutants from seafood will not reach excessive levels. Therefore, many measures that help maintain nutritional balance are also beneficial for improving food safety.
Fourth danger: Food allergies and intolerances
From a global perspective, crustaceans and fish, eggs, and milk are the most allergenic animal foods. For the Chinese population, shrimp, crabs, and other seafood are the most common food categories that cause allergies in adults. Many of the allergenic proteins have been studied, but these substances that cause allergies cannot be eliminated by steaming for 10 minutes.
In addition to allergies, many people have intolerant reactions to seafood and river crabs and feel gastrointestinal discomfort after eating them. Some people believe that it is because the proteins in them are difficult to digest, while others believe it is related to algal toxins or pathogenic bacteria. Regardless of the reason, if there are adverse reactions, one should stay away from these foods, at least temporarily.
Fifth danger: Excessive consumption of seafood and river crabs may lead to gout and also increase the burden on the liver and kidneys. The intake of seafood and river crabs is closely related to the risk of gout, as evidenced by numerous investigations worldwide. Since excessive intake of these foods can bring in a large amount of protein, people with impaired liver and kidney function should strictly limit their intake and not indulge indiscriminately.
In conclusion, friends with high blood uric acid and gout, people with impaired liver and kidney function, people with weak digestive systems and insufficient stomach acid, people who are prone to diarrhea or have chronic gastroenteritis, must control their appetites and limit their consumption of seafood and river crabs. Even if the food is delicious, one should not "sacrifice oneself for food." If you really get sick from eating, it will bring trouble to the joyous festival.
