Crabs, along with lobsters, crayfish, and muscles, are among the edible crustaceans that are enjoyed by millions of people throughout the world each year.
They serve as an important source of protein and are standard fare in some of the finest restaurants. The standard method of cooking live crab, however, is a controversial issue that some feel is cruel and contrary to animal welfare.
The alternative of cooking already-dead crustaceans can be dangerous to one’s health, due to the bacteria that lurks beneath their shells.
Do crabs and other crustaceans hold a health risk to humans?
The Journal of Food Protection published a study conducted by the National Research Institute of Fisheries Science that supports the theory that crustaceans, such as crabs, do indeed present a health risk to humans that increases when they are not handled properly during processing.
Those who choose to cook crabs after they are deceased, rather than cooking them alive, take potentially fatal health risks.
How does boiling crabs alive affect the presence of dangerous bacterium?
According to an article in Science Focus (online), when crustaceans die, the dangerous, harmful bacteria found in and on their bodies and shells can multiply quickly, releasing toxins from crab meat that may not be destroyed simply by cooking. This is used as the rationale behind cooking them alive.
Vibrio parahaemolyticus bacterium
Among a variety of other pathogens, researchers studying crabs and other crustaceans have discovered a particularly dangerous marine bacterium, Vibrio parahaemolyticus bacterium, that can cause food-borne diseases.
Researchers looked at both salt water and fresh water crabs and discovered that this dangerous bacterium appeared in the bodies, shells, and feces of a number of crab species. The study focused on crabs in Chinese markets where live animals and produce are sold for human consumption.
The bacterium can spread through the animals’ bodies almost immediately after death and has the potential to spread to other crustaceans.
The Journal of Food Protection also advises throwing away any dead shellfish and other crustaceans if they die prior to being cooked. The journal also advises against eating shellfish, including crab, that is raw.
What types of illnesses can be caused by eating crabs containing Vibrio parahaemolyticus?
According to the Journal of Infectious Diseases (2000), Vibrio parahaemolyticus bacterium found in crustaceans like crabs frequently occurs in marine animals’ natural environments in both shallow and deep water.
This bacterium is known to cause at least three diseases, including gastroenteritis, which is the most common of the three. Other possibilities include advanced infections to wounds, and septicemia, a blood infection that is potentially fatal.
Does boiling crabs alive cause the animals to experience pain?
The jury is still out with regard to whether crustaceans experience pain when they are boiled alive, and there is more than one perspective on this issue.
The aforementioned article in Science Focus notes that some people argue that crustaceans do not possess true brains, and therefore, cannot feel pain as sentient beings.
This conclusion was reached after observing that some crustaceans will contort their bodies and make violent attempts to extricate themselves from the boiling water. The article concludes that these animals do not possess the same type of self-awareness as humans, but that they do exhibit both hormonal and physical responses to tissue damage.
The study went on to say that crustaceans produce cortisol just as humans do when pain is experienced, leading researchers to conclude that shelled marine animals do experience pain. It simply is not clear to what degree they experience it, or if it is pain identical to that experienced by humans.
What are some humane ways to kill crabs and other crustaceans?
In a study written for the Journal of Shellfish Research by Chapman (1992) and Cook, (1996) in 1997, researchers noted that efforts to kill crustaceans like crabs humanely developed the goal of inflicting as little pain as possible during their slaughter.
However, the researchers also took into account the fact that the measurement of pain is a very difficult, if not impossible, thing to measure accurately where animals are concerned, because they do not possess languages that are understandable by humans.
Therefore, attempts at measuring the animals’ levels of pain are usually estimated by changes in their behaviors that appear to indicate that they are in distress.
For instance, a lobster’s tail will twitch for approximately two minutes after the animal is plunged into boiling water, indicating that the animal might be experiencing pain. The authors of the study also noted that changes in the animals’ behavior that make their distress undetectable can be affected by inducing paralysis.
Since the animals are intended for human consumption, different chemicals are used for those particular crabs, as opposed to the ones that are used for research.
Adding to the controversy is the fact that paralyzing crustaceans, however, does not necessarily mean that they will not feel pain when scalded.
It simply means that indications of their pain will not be noticeable to those who cook them, making the practice of boiling the marine animals alive possibly more comfortable for the cooks, but not for the animals who may or may not still experience the associated pain.
Conversely, the view that boiling crabs and other crustaceans alive is cruel has been taken to new heights in the United Kingdom and in a number of other countries.
According to an article in The Guardian, Dr. Stephanie Yu, Ph.D. Noted in her report prepared for the U.S. Humane Society that, “There exists robust scientific evidence in support of crustaceans being sentient animals with the capacity to suffer.”
As a response, a bill has been presented to the House of Lords in England that calls for changes to laws governing the treatment of animals and asks that it include crab, squid, and other sentient invertebrates.
The bill specifies that those who plan to cook, or otherwise kill any of these animals will need to stun them before they are boiled. One method of doing this is by chilling them.
According to Science Magazine, scalding crustaceans to death so that they may be eaten is unnecessary torture that the animals should not have to endure. The author notes that these marine animals can be painlessly killed by placing them in cold, fresh water and raising its temperature to approximately 40°C or replacing their protein with a seafood alternative from a company like BlueNalu.
Alternatively Ray, Fleckenstein, Medley , et al (2018), conducted a study that involved stunning crabs with an electrical shock prior to boiling them, resulting in fewer incidences that indicated the animals were in pain.
- Weineck, K.; Ray, A.J.; Fleckenstein, L.J.; Medley, M.; Dzubuk, N.; Piana, E.; Cooper, R.L. Physiological Changes as a Measure of Crustacean Welfare under Different Standardized Stunning Techniques: Cooling and Electroshock. Animals 2018, 8, 158. [Google Scholar] [CrossRef] [PubMed]
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- Cook, C. 1996. Pain in farmed animals, awareness, recognition and treatment. pp. 75-81. In: R. Baker, R. Einstein and D. Mellor (eds.). Farm Animals in Biomedical and Agricultural Research. ANZCCART, Adelaide, South Australia.
- Chapman, C.R. 1992. Suffering in animals: towards comprehensive definition and measurement for animal care. pp. 19-25. In: T.R. Kuchel, M. Rose and J. Burrell (eds.). Animal Pain: Ethical and Scientific Perspectives. ANZCCART, Adelaide, South Australia.
- Gardner, C. 1997. Options for humanely immobilizing and killing crabs. Journal of Shellfish Research. 16(1): 219-224;
- Journal of Food Protection, Vol. 69, No. 11, 2006, Pages 2742-2746
- The Journal of Infectious Diseases, Volume 181, Issue 5, May 2000, Pages 1661-1666, https://doi.org/10.1086/315459