Tips

How to Tell Healthy Crabs from Toxic Ones When Buying Seafood

"Crab is a nutrient-rich delicacy, but it can be dangerous if you don't know what to look out for. With a multitude of species out there, some crabs can be highly toxic and even deadly. It is imperative that you familiarize yourself with the key identification features of poisonous crabs to avoid any unfortunate incidents. A little knowledge goes a long way in keeping you safe and ensuring a pleasant dining experience."

Administrator

13 July, 2024

Dangers of Poisonous Crabs

Poisonous crabs contain two extremely potent toxins, Saxitonin and Tetrodotoxin. If exposed to these toxins, after a period of 20 minutes to 3 hours, one may experience the following symptoms:

– Numbness and a burning sensation in the lips and tongue.

– Abdominal pain and nausea.

– Violent vomiting.

– Numbness and tingling in the hands and feet, leading to unsteady gait.

– Headache, dizziness, and altered mental status.

– Deep unconsciousness.

If not treated promptly, consumption of poisonous crabs can result in respiratory failure, throat swelling, cardiac arrest, and even death within 30 minutes to 8 hours.

How to Distinguish Between Safe and Poisonous Crabs

– Poisonous crabs often have bright and unusual colors, with spots, stripes, or bumps on their shells.

– Safe crabs have less striking colors, usually greenish or dark brown, with smooth shells and white bellies, and little to no hair.

– Poisonous crabs often inhabit coral reefs and may feed on toxic marine organisms, causing their meat to become toxic.

– It is advisable to purchase crabs from reputable and quality sources. Avoid consuming crabs that have been dead for a prolonged period, as they may produce the toxin Histamine, which can lead to unconsciousness, respiratory failure, and death.

Identifying Poisonous Crab Species Found in Vietnamese Waters

There are currently four extremely poisonous crab species found in Vietnamese waters that should be avoided at all costs.

– The Stone Crab: This crab has a dark purple shell, an elliptical body shape, a round shell, long legs, and short claws.

– The Ghost Crab: The widest part of its shell is approximately 90 mm, and it is about 55 mm long, with numerous flat-topped bumps. The live crab is colored in a mix of sky blue and green, with white, brown, and yellow bands. Its legs and claws are dark brown.

– The Florida Stone Crab: This crab has an elliptical body shape and a reddish-purple color with small red spots.

– The Grainy Crab: This crab has a semi-circular shape, and its shell is covered with grains, giving it a dark greenish-yellow, brownish-yellow, or reddish-purple color. The toe joints are black.

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Frequently asked questions

There are several key indicators to look for when selecting live crabs. Firstly, assess their activity level – healthy crabs are active and move around vigorously. Check their claws and legs; they should be intact and firmly attached. Healthy crabs also have a hard, shiny shell, and their gills should be a vibrant red or purple color. Avoid crabs with damaged shells, missing limbs, or discolored gills, as these are signs of potential illness or stress.

Toxic crabs often exhibit visible signs of contamination. Look out for abnormal behavior such as lethargy or a lack of movement. Discolored or damaged shells, particularly with white spots or a yellow tint, can indicate the presence of toxins. Also, check the odor; a strong, unpleasant smell could suggest the crab is unsafe to consume. If you have any doubts about the crab’s freshness or safety, it’s best to avoid purchasing it.

When buying crabs, it’s important to source them from a reputable supplier or fish market. Ask about the crabs’ origin and how they were caught or farmed. Wild-caught crabs tend to have better flavor and texture. Check the eyes of the crab; they should be clear and not cloudy, which could indicate a loss of freshness. Lastly, avoid any crabs that feel light for their size, as this may suggest dehydration or a lower meat yield.

Crab meat is an excellent source of high-quality protein and contains a range of essential vitamins and minerals. It’s particularly rich in vitamin B12, which is important for maintaining healthy nerve and blood cells. Crab meat also provides a good amount of selenium, which has antioxidant properties, and omega-3 fatty acids, which are beneficial for heart health and cognitive function.

To keep live crabs fresh, it’s important to store them properly. Place the crabs in a well-ventilated container, such as a cardboard box, and line it with damp newspaper or seaweed. Keep the container cool and well-aerated, ideally at a temperature between 35-45°F. Sprinkling the crabs with seawater or fresh water occasionally can help maintain humidity and keep them hydrated. Crabs stored this way can remain alive and fresh for several days.