Rather than worrying about whether you can eat shrimp heads, you should pay more attention to this issue.

Audit expert: Wang Guoyi

Postdoctoral fellow in Nutrition and Food Safety, China Agricultural University

If we talk about summer must-have delicacies, crayfish must be at the top of the list. On a hot summer night, eating a bite of spicy and delicious crayfish and drinking a sip of cold beer will make you feel refreshed.

However, when eating crayfish, everyone always argues about one question - can the crayfish head be eaten?

Eating shrimp heads actually means eating the yellow stuff inside the shrimp heads. What are these? Some people think that this is shrimp roe, which is rich in nutrients, while others think that this is "shrimp feces", which contains toxic substances and must not be eaten. So which statement is correct?

Source: Baidu Encyclopedia

1

Is that poop in the shrimp head?

Let me tell you the answer first. The yellow substance in the shrimp head is not poop , so you can rest assured.

So what is it? First we need to understand the body structure of crayfish.

Although lobsters are small, they have all the internal organs. Their head (cephalothorax) includes many internal organs, such as heart, gills, stomach, hepatopancreas, reproductive organs, etc., and depending on the gender, there are ovaries and testes .

Shrimp have two holes for excretion. One is responsible for excreting urine, which is located on the head; the other is for excreting other digestive products, which is located near the shrimp's tail, that is, the end of the shrimp line.

Source: Xue Junzeng, Wu Huixian, Zhang Liping. Morphological anatomy of Procambarus clarkii as a substitute for shrimp in crustacean experiments. Journal of Fuling Teachers College, 1998

In other words, shrimp feces are not discharged from the shrimp's cephalothorax. Therefore, the yellow substance we see on the shrimp's head is actually the shrimp's various digestive glands and reproductive glands , which corresponds to the crab roe and crab paste of the crab, and is not feces.

Crayfish, source: pixabay

In this case, can we still eat shrimp roe? Will eating shrimp digestive glands have any effect on our body?

2

Can shrimp roe be eaten?

When shrimps obtain nutrients, they also take in pollutants from the environment. These pollutants enter the shrimp's body and participate in its metabolic process. Because the main organs of shrimps are concentrated in the head, the main metabolic process also takes place in the shrimp's head .

In animal feeding behavior, there is a phenomenon called "bioenrichment". For example, if a snail contains 1 unit of heavy metal pollutants that cannot be metabolized, when a crayfish eats ten snails, the heavy metal pollutants in the crayfish's body become 10. If a catfish eats ten such crayfish, the pollutants in the catfish's body become 100. At this time, if a person eats catfish again, it is likely that only a small amount will cause poisoning.

Although as far as heavy metals are concerned, crayfish will concentrate some heavy metals (such as chromium and lead) and transfer them to their shells, and then excrete them through growth and molting, there will always be some harmful substances remaining in the shrimp's body.

In general, the content of toxic substances in shrimp heads is higher than that in shrimp meat.

High levels of heavy metals in crayfish liver and shell Source: Zhou Lizhi, Chen Chunling, Zhang Lei, et al. Accumulation characteristics of three heavy metals in Procambarus clarkii. Journal of Ecology, 2008

Of course, the content of harmful substances mentioned above is only relative. If we buy lobsters from formal channels, the water quality for breeding is relatively guaranteed, and the content of toxic substances in the shrimp heads will not exceed the national safety standards. Therefore, normal consumption will not have much impact on the human body and there is no need to worry too much .

In short, if the crayfish comes from a regular source, you can eat the shrimp head and the shrimp roe inside. If you still feel uncomfortable psychologically, just peel off the shrimp head and eat the meat.

Source: pixabay

3

How to eat crayfish correctly?

First of all, when buying crayfish, you should choose fresh live shrimps with no peculiar smell, elastic meat, clean shells and less dirt. Because the body tissues of dead shrimps will quickly necrotize and breed a large number of bacteria. If they are not thoroughly cooked, it is easy to get an upset stomach.

When buying live shrimp, choose crayfish from farms instead of wild lobsters. Because the living environment of wild lobsters is not controlled, crayfish have strong survival ability and can survive even in very dirty waters, but the heavy metals enriched in their bodies are likely to exceed the standard, which is naturally harmful to human health.

Secondly, when cleaning crayfish, you must brush them carefully with a brush. You can remove the shrimp thread (the intestines of the crayfish) and consider cutting off the part with the shrimp stomach at the front of the shrimp head.

Lobster tail source: pixabay

Compared to whether you can eat shrimp heads, another issue that needs to be paid attention to is that when cooking crayfish, they must be cooked thoroughly! Even shrimps that are farmed in a formal way can carry bacteria and parasites, and can only be eaten safely if they are cooked thoroughly at high temperatures.

There are also some rules to follow when it comes to the amount of cooked crayfish you eat.

The purine content of crayfish is relatively high. If you have high uric acid, abnormal purine metabolism, or a history of gout, it is better to eat less to avoid excessive purine intake which may induce gouty arthritis.

Crayfish is also rich in protein, but for people with weak gastrointestinal digestion ability, eating too much crayfish can easily increase the burden on the gastrointestinal tract, so it is recommended to eat it in moderation.

In addition, the protein contained in crayfish is a "foreign protein". For some people with allergies, these "foreign proteins" can easily induce allergic reactions , such as wheals, throat edema, etc., which can even be life-threatening in severe cases. It is recommended that people with allergies do not eat it.

Crayfish source: pixabay

In short, as long as the crayfish is purchased through regular channels, the shrimp heads can be eaten. Whether to eat it depends on personal preference. For children, the elderly, pregnant women and other groups, in order to ensure safety, it is recommended to eat less or no shrimp heads.

But don't try the half-cooked shrimp.