The weather has gradually warmed, and the summer many people have longed for is coming. Barbecue stalls, food stalls and other street food that foodies like are gradually becoming popular. Grilled skewers, grilled squid, and small fried snails are all mouth-watering. But wait, don’t eat “snail-flavored food” indiscriminately, be careful of infecting parasites.
It turns out that many people can’t tell the difference between Fushou snails and field snails.
So, how to distinguish Fushou snails and field snails? In addition to “snail”, what other foods should never be eaten raw? Today, let’s talk about it in detail
01 Eating snails is very harmful
▲Picture: from Micro Bo
Do you still remember the Guangzhou Angiostrongylus epidemic that occurred in Beijing in July 2006? The reason is that the diners were infected with Angiostrongylia cantonii by eating the cold mixed snails in restaurants. There were more than 100 patients involved, and many of the patients had symptoms such as headaches and convulsions. In August 2006, the Beijing Center for Disease Control and Prevention checked 97 Fushou snails on the market from the major aquatic markets in the city. Among them, 9 snails were found to be parasitized by the first or second stage larvae of Angiostrongylus cantonii. [1] Similar cases have appeared sporadically in recent years, and even pregnant women have lost their unborn children.
So where did this snail come from, and why is it so dangerous?
Fu Shou snails, also known as big bottle snails, snow snails, and apple snails, are native to the Amazon River Basin in South America. Because Fushou snail is rich in protein, it was introduced into Guangdong, Fujian, Shanghai and other places in my country as an aquatic economic organism in 1980, and was abandoned because of its poor taste. Because of its strong reproductive ability, an adult female snail lays more than 325,000 eggs per year, which quickly spread to water environments such as paddy fields and water bamboo fields. [2]
In 2003, the former State Environmental Protection Administration listed Fushou snail as one of the major and dangerous agricultural invasive alien species, and included it in the “China’s First Batch of Invasive Alien Species List”.
The snail can easily parasitize Angiostrongylus cantonii. A single snail can have more than 6,000 Angiostrongylus larvae. This parasite can Humans were infected by eating undercooked snails.
▲Picture: Reference [3]
The third stage larvae of Angiostrongylus cantonis migrate through the central nervous system in the human body It can develop into fourth and fifth stage larvae. Because the human body is not the normal host of Angiostrongylus cantonii, it cannot descend to the pulmonary artery to develop into an adult worm, which will migrate to the nervous system for a long time and induce meningitis. May develop into adults. [4]
Infection with Angiostrongylus cantonensis can cause severe headache, nausea, vomiting, fever, coma, mental disorders and other symptoms, and even death in severe cases. To avoid contracting this parasite, it is recommended to cook the snails thoroughly, or not to eat them at all!
02 Fushou snail and field snail, what’s the difference?
▲Picture: Source Network
Many people are not infected with parasites because of active consumption of snails, but The tragedy was caused by mistaking Fushou snails for eating snails. Fushou snails and field snails are similar in appearance, but if you look closely, there are still many differences between the two.
①Shell: The shell of the juvenile Fushou snail is brittle and will break when you pinch it;
②Color: The shell color of Fushou snail is yellowish brown; the shell color of field snail is more blue-brown.
③Shape: The tail of Fushou snail is flat and short, and the helix of the tail is short conical;
④Opening: The opening of Fushou snail is larger and the screw cap is flat; the snail screw is smaller and the cap is round.
⑤Egg color: The eggs of Fushou snails are pink; the eggs of field snails are transparent.
▲Picture: Reference [5]
In addition, It is recommended not to order Fushou snails out of curiosity, because There’s still a risk if the chef doesn’t cook it well.
03 These 5 kinds of food can’t be eaten raw
In addition to the snail, the following 5 kinds of food are also hidden around people” Dangerous elements”, need to be vigilant:
Eel: The meat is delicious and is called “ginseng in water”. However, eel is the intermediate host of at least 15 kinds of parasites, among which the most harmful is the third stage larvae of Jaw-mouth nematode. People are mostly infected by eating raw eel or eating undercooked eel, and the larvae will swim in multiple organs in the human body. Internal organs, eyes, brain, spinal cord and other organs. [7]
Salmon: Many people like to eat raw salmon, thinking that it is a very nutritious fish. But from a safety point of view, it is really not recommended to eat raw. Raw salmon is likely to be contaminated with parasites, mainly S. broad-segmented tapeworm. When eaten by humans, the schizophrenia enters the human body and develops into adult worms in its intestines after 3 to 5 weeks. Most infected people have no obvious symptoms, and a few have mild symptoms such as fatigue, weakness, numbness of limbs, diarrhea or constipation and hunger, which affect human health. [8]
▲Splide-headed tapeworm
So is it okay to eat raw salmon with mustard? Not oh! Although mustard is rich in isothiocyanates, which can inhibit the growth of microorganisms, but cannot kill the sporocysts in fish muscles.
Crayfish and crabs: For those who like to eat drunken shrimp and crabs, they need to be alert to paragonimiasis. Raw and undercooked crayfish and crabs may be contaminated with paragonimiasis. Paragonimus parasites are mainly parasitic in the lungs of humans or mammals, but also in the cerebrospinal, abdominal cavity and subcutaneous tissue, which damages health.
Water chestnuts: A type of aquatic plant that is easily infected with Fasciola chinensis. After a person is infected with Fasciola chinensis, the stool volume will increase, the smell is particularly foul, and it also contains undigested food. A few patients will also excrete some Fasciola chinensis from the feces, or even spit it out of the mouth. Abdominal pain, diarrhea, nausea, vomiting, fever, allergies, and edema may occur. In severe cases, intestinal obstruction and even death may occur. Children infected will also affect physical and intellectual development. [9]
04 How to avoid parasite infection while enjoying delicious food?
Do not eat raw aquatic plants and meat: Such as snails, water chestnuts, lotus roots, drunk shrimp, Drunk crab, salmon, etc. If you want to eat it, be sure to cook it thoroughly!
Separation of raw and cooked cutting boards: Usually sharing a cutting board for raw and cooked foods may lead to cross-contamination. It is recommended that you must separate raw and cooked, use different cutting boards, or cut vegetables and fruits on the front and raw meat on the back. After cutting raw meat, be sure to wash the cutting board thoroughly and hang it to dry.
Don’t drink raw water: There may be some parasite eggs and bacteria in raw water, especially in rivers, rivers, streams, etc., no matter how clear it is Just drink it! Even tap water, be sure to boil it before drinking it.
Wash your hands frequently: Pay attention to personal hygiene, wash your hands frequently, and avoid the eggs that may be carried on your hands from adhering to daily necessities and food.
Summary:
Parasites are very harmful to the human body, so don’t eat them raw just to take a bite of the so-called “fresh” safe food. In terms of the choice of ingredients, it is recommended to buy from regular supermarkets. Also, pay attention to personal hygiene!
Review | Chen Shengjun, Researcher, South China Sea Institute, Chinese Academy of Fishery Sciences
References:
[1] He Zhanying, Jia Lei, Huang Fang, etc. Beijing An outbreak investigation of angiostrongyliasis in Guangzhou[J].Chinese Public Health,2007,23(10)
:1241-1242.DOI:10.3321/j.issn:1001-0580.2007.10.049.< /p>
[2] Wang Chanjuan, Song Zengfu, Lu Xian, Wang Ling, Luo Nan, Yao Linong, Zhang Yinjiang. Research progress on the invasion and prevention of snails in China[J].Journal of Biosafety,2021,30 (03):178-182.
[3] Wang Fei, Cao Shuzhen, Zhang Xiaoxiao, et al. Research status of growth, development and morphological characteristics of Angiostrongylia in Guangzhou[J].International Journal of Medical Parasitic Diseases,2013,40 (4)
:225-230.DOI:10.3760/cma.j.issn.1673-4122.2013.04.011.
[4] WS321—2010 Diagnosis of Angiostrongyliasis in Guangzhou Standard
[5] Ren He, Gao Hongjuan, Xue Juan, Gong Ning, Chen Xiang. Biological characteristics and control of snails in Fushou [J]. Bulletin of Biology, 2020, 55(12): 1-3 .
[6] Yang Yuexin. Chinese Food Composition Table 6th Edition Vol. 2 [M]. Peking University Medical Press, 2018
[7] Cai Wuwei, Lin Chenxin, Xie Hanguo, Jiang Dianwei. Investigation on the distribution of the third stage larvae of Jaw-mouth nematode in Eel [J]. Strait Journal of Preventive Medicine, 2020,26(02):10-11+42.
[8] Li Yanrong, Li Lisha, Jiang Dianwei , Chen Zhuyun.Report of a case of raw-eating salmon infected with Schizophrenia lata[J].Chinese Journal of Parasitology and Parasitic Diseases,2013,31(06):494.
[9] Zhou Qing, Peng Qingqing, Qiu Jinbo, et al. Research progress on the diagnosis and control of fascioliasis in ginger[J]. Chinese and Foreign Health Digest, 2014, (23): 108-109.