Crassostrea virginica /Oyster is the common name for a number of different families of salt-water bivalve mollusks that live in marine or brackish habitats. In some species, the valves are highly calcified, and many are somewhat irregular in shape. Many, but not all oysters are in the superfamily Ostreoidea.

Some types of oysters are commonly consumed cooked or raw, and in some locales are regarded as a delicacy. Some types of pearl oysters are harvested for the pearl produced within the mantle. Windowpane oysters are harvested for their translucent shells, which are used to make various kinds of decorative objects.

 

Oysters are one type of bivalve mollusks that are consumed throughout the world. There are several varieties of oysters, some of which mostly create pearls, and these are not typically consumed by people, but the variety of oysters bearing the scientific family name of Ostreidae are normally eaten as a delicacy. These are also called true oysters, while feathered oysters (those bearing pearls) are in a distant family called Pteriidae. Edible oysters have been a part of the human diet for at least 700 years, but have likely been eaten in raw or cooked forms for much longer.

 

The most commonly used oysters are windowpane oysters, which are harvested for their translucent shells and different decoration pieces are made from them. The word oyster was first used in the 14th century, which is derived from the Old French word ‘moisture. This French word is in turn derived from the Latin word ‘Astrea’s.

Physical Appearance

Oyster is the name given to the different families of bivalve mollusks and saltwater clams that live in the marine environment. The outer covering shell is normally oval or pear-shaped but will vary widely in form depending on what they attach to. Normally they are somewhat irregular in shape about 4 to 6 in. (10–15 cm) long. The shell is made up of two valves, the upper one flat and the lower convex, with variable outlines and a rough outer surface. Shell is whitish-gray colored and edible components are the meat inside the oyster that is porcelain white-colored and once the shells have been cracked, you can cook this meat in a variety of ways, but they can also be eaten raw and is often favored in that way. Meat has a delicate, toothy texture, rich flavor, and salty liquor.

History of Oysters

There is a long link to oysters and love. It is reputed for its aphrodisiac powers and is preferred for centuries by lovers, as far back as the Roman emperors. The Greek goddess of love was said to have appeared from the sea on an oyster shell, instantly giving birth to Eros and the word “aphrodisiac”. The famous Casanova, renowned lover, would start a meal, dining on 12 dozen oysters.

Whether it’s for Valentine’s Day or any day, Whole Foods Market has kindly shared their tips and tricks for buying and preparing oysters at home. For oyster-loving people or that budding Casanova looking for ways to sweep their sweetheart off her feet, Whole Foods Market has the perfect aphrodisiac – a romantic and gourmet Valentine’s Day experience at home with oysters.

Types of Oysters

There are over 150 varieties of oysters harvested and sold in North America, yet they comprise a total of only 5 species of oysters. And although each species does have its general characteristics in regards to flavor, their “finishing touches” can be attributed more to their merroir (local habitat) than to their species. In this sense, oysters are much like fine wine…each one is distinctly different from each other as they take on the flavors indigenous to the regions and conditions under which they were grown.

1. Pacific Oysters – Crassostrea gigas

Pacific oysters are small and sweet and the world’s most cultivated oyster. They are growing in popularity in both Europe and the West Coast, where they are starting to over-run the native Olympia. Pacific oysters are used to describe all small Pacific oysters like Kumamotos and Miyagis. Kumamotos, however, were found to be their own species. Pacific has a distinctly more fluted, sharply pointed shell than Atlantics or European flats.

2. Kumamoto Oysters – Crassostrea sikamea

Kumamotos are small, sweet, almost nutty oysters considered by their deep, almost bowl-shaped shell. Like Pacifics, they have deeply fluted, sharp, pointy shells. They spawn later and in warmer water than other oysters, so they remain firm and sweet well into the summer months. Kumamotos are widely cultivated in Japan and the West Coast. The name Kumamoto is so valued that Kumamotos are always considered as such, although some places will also specify where they are from.

3. Atlantic Oysters – Crassostrea virginica

Atlantic Oysters are the “great American oyster” and are naturally found along the North American Atlantic Coast from Canada southward to the Gulf of Mexico. Along with the Olympia Oyster, they are the only indigenous oyster found in North America. They are distinctly different than Pacific oysters in that they tend to be larger, have a teardrop or paisley shape, smooth shells, and uniform colors of brown, cream and forest green

4. European Flat Oysters – Ostrea edulis

European flats are often known as Belongs. While Belongs is, certainly European flats, not all European flats are Belongs (Belongs must be grown in the Brittany region of France). Once the most common oyster in Europe, Europeans are progressively appreciative of Pacific oysters while Maine and Washington state oyster farms are increasingly charmed by European flats.

European flats are considered by their smooth flat shell (no surprise there!) and lovely seaweed and sharp mineral taste. They have a meaty texture and, for those used to different kinds of oysters, almost a crunch to them.

5. Olympia Oysters – Ostrea lurida /Ostrea conchaphila

]Olympias are the only oyster indigenous to the US Pacific West Coast. They were so popular during the Gold Rush era that by the end of the 1800s they were wiped out and for many years thought to be extinct. But some wild stock was eventually found in the Pacific Northwest and is now cultivated successfully by a few farmers.

Other Varieties

1. Blue Point Oysters (Long Island, NY)

Named after the town of Blue Point, Long Island, these are perhaps the oysters you will most commonly find on the East Coast side of your raw bar. These medium-sized oysters are mild, pleasantly salty, and very meaty. Blue points are great beginner oysters, as they won’t overwhelm you, and go well with a classic spicy cocktail sauce or this celery seed and dill spiked version.

2. Malpeque Oysters (Prince Edward Island, Canada)

Malpeque oysters have very tender meat, with a nice balance of brininess and sweetness. These crisp oysters are occasionally said to taste a bit like lettuce. A little lemon and a dab of horseradish should be all you need on these beauties.

3. Beau Soleil Oysters (New Brunswick, Canada)

Beau Soleil oysters are Canadians as well, but these meaty bivalves hail from New Brunswick. These oysters are known for their deep cups and meaty texture, which means they can stand up to this spiced-up, citrusy mignonette.

4. Chincoteague Oysters (Chincoteague Island, VA)

These southerners can be tricky, as they are often impersonated. True Chincoteague’s are long, skinny things with plenty of salinity and a sweet finish. But, other oysters are often brought to Chincoteague’s waters to hang out in a salt bath for a bit, making them mostly just salty. If you get true Chincoteague, enjoy them on the half shell. If you get imposters, don’t despair — this is a great time to give broiled oysters a whirl.

5. WiAnno Oysters (Cape Cod, MA)

WiAnno oysters are cultivated in a protected in calm, protected beach waters, which make them incredibly clean and quick to grow plump. Because they grow so quickly, their shells can be brittle, making them harder to shuck. If this gives you trouble, it’s a great time to try grilling your oysters — pop them on whole and they open up when they’re ready!

6. Duxbury Oysters (Cape Cod, MA)

Duxbury oysters are grown in some of the coldest water in the Cape Cod bay, meaning they never go into spawn, but they do fatten up as if they are going to. This means that they have deep cups filled with fatty meat that has an extremely buttery finish. These are delightful raw, but because their fat content keeps them from drying out, they are also great candidates for roasting.

7. Quonset Point Oysters (Narragansett Bay, RI)

These small, delicate oysters from calm Rhode Island waters are mild, briny, and clean. They are only for advanced suckers, however, as these pampered mollusks have very dainty shells. Definitely eat these raw.

8. Belon Oysters (Damariscotta River, ME)

Belon oysters are not for beginners. This European flat breed is unlike any oyster you’ve ever seen or tasted. They have a very strong flavor, more minerally than briny, and are massive and meaty. They are also pretty rare, so if you get the chance, dive in.

Proximity	Amount	% DV
Water	55.01 g	N/D
Energy	169 Kcal	N/D
Energy	707 kJ	N/D
Protein	7.45 g	14.90%
Total Fat (lipid)	10.69 g	30.54%
Ash	1.46 g	N/D
Carbohydrate	9.88 g	7.60%

Minerals	Amount	% DV
Calcium, Ca	53 mg	5.30%
Iron, Fe	5.91 mg	73.88%
Magnesium, Mg	49 mg	11.67%
Phosphorus, P	135 mg	19.29%
Potassium, K	207 mg	4.40%
Sodium, Na	354 mg	23.60%
Zinc, Zn	74.06 mg	673.27%
Copper, Cu	3.65 mg	405.56%
Manganese, Mn	0.416 mg	18.09%
Selenium, Se	56.5 µg	102.73%

Vitamins	Amount	% DV
Water-soluble Vitamins
Vitamin B1 (Thiamin)	0.128 mg	10.67%
Vitamin B2 (Riboflavin)	0.172 mg	13.23%
Vitamin B3 (Niacin)	1.403 mg	8.77%
Vitamin B5 (Pantothenic acid)	0.23 mg	4.60%
Vitamin B6 (Pyridoxine)	0.054 mg	4.15%
Vitamin B9 (Folate)	26 µg	6.50%
Folic Acid	14 µg	N/D
Folate, food	12 µg	N/D
Folate, DEF	37 µg	N/D
Vitamin B-12 (Cobalamine)	13.29 µg	553.75%
Vitamin C (Ascorbic acid)	3.2 mg	3.56%
Fat-soluble Vitamins
Vitamin A, RAE	76 µg	10.86%
Vitamin A, IU	257 IU	N/D

Lipids	Amount	% DV
Fatty acids, total saturated	2.717 g	N/D
Myristic acid  14:00(Tetradecanoic acid)	0.128 g	N/D
Palmitic acid 16:00 (Hexadecanoic acid)	1.623 g	N/D
Stearic acid 18:00 (Octadecanoic acid)	0.944 g	N/D
Fatty acids, total monounsaturated	3.997 g	N/D
Palmitoleic acid 16:1 (hexadecenoic acid)	0.078 g	N/D
Oleic acid 18:1 (octadecenoic acid)	3.774 g	N/D
Gadoleic acid 20:1 (eicosenoic acid)	0.048 g	N/D
Erucic acid 22:1 (docosenoic acid)	0.008 g	N/D
Fatty acids, total polyunsaturated	2.816 g	N/D
Linoleic acid 18:2 (octadecadienoic acid)	2.074 g	N/D
Linolenic acid 18:3 (Octadecatrienoic acid)	0.133 g	N/D
18:04	0.078 g	N/D
Arachidonic acid 20:4 (Eicosatetraenoic acid)	0.06 g	N/D
20:5 n-3 (EPA)	0.172 g	N/D
22:5 n-3 (DPA)	0.041 g	N/D
22:6 n-3 (DHA)	0.185 g	N/D
Cholesterol	60 mg	N/D

Amino acids	Amount	% DV
Tryptophan	0.089 g	20.23%
Threonine	0.31 g	17.61%
Isoleucine	0.337 g	20.16%
Leucine	0.542 g	14.66%
Lysine	0.495 g	14.80%
Methionine	0.169 g	N/D
Cystine	0.111 g	N/D
Phenylalanine	0.299 g	N/D
Tyrosine	0.246 g	N/D
Valine	0.348 g	16.48%
Arginine	0.497 g	N/D
Histidine	0.149 g	12.09%
Alanine	0.417 g	N/D
Aspartic acid	0.665 g	N/D
Glutamic acid	1.271 g	N/D
Glycine	0.419 g	N/D
Proline	0.399 g	N/D
Serine	0.365 g	N/D

*Above mentioned Percent Daily Values (%DVs) are based on 2,000 calorie diet intake. Daily values (DVs) may be different depending upon your daily calorie needs. Mentioned values are recommended by the U.S. Department of Agriculture. They are not healthbenefitstimes.com recommendations. Calculations are based on average age of 19 to 50 years and weigh 194 lbs. Source: https://ndb.nal.usda.gov/

Health Benefits of Oysters

Oysters are unusual and delicious mollusks that offer the human body a number of unique nutrients and minerals, which subsequently result in some great health benefits. These include the ability of oysters to aid weight loss attempts, boost metabolic activity, increase tissue repair and growth, lower your cholesterol levels, reduce blood pressure, improve your immune functions, aid in wound healing, and promote healthy growth. Furthermore, they are considered a powerful aphrodisiac, can improve blood circulation, and increase bone strength to reduce osteoporosis.

1. Weight Loss

Oysters represent one of the most nutrient-packed foods with the lowest calories versus the volume of serving size. This means that people trying to lose weight can keep their body packed with the nutrients it needs, without adding too much weight on their frame. Compared to an equal serving size of the chicken, oysters have nearly half the calories, and chicken breasts are often turned to for low-calorie, protein-rich meals. Oysters are far superior in this respect, except they do have a high content of sodium, so for people already suffering from obesity, oysters may worsen the problem.(1)

2. Heart Health

There are numerous nutrients responsible for the benefits of oysters on heart health.

But in general, fatty acids are the main contributor. Specifically, with a substantial amount of omega-3 fatty acids, oysters can encourage the number of good cholesterol and obstruct the increase in bad cholesterol. This will prevent these cholesterols from concentrating on the arteries, which increases the blood pressure dramatically.

Moreover, minerals in oysters are supportive of the cardiovascular system as well.  Magnesium and potassium also have a positive influence on reducing blood pressure and relieving tension in blood vessels. Moreover, oysters provide vitamin E that might make cellular membranes stronger and more flexible.(2), (3), (4), (5), (6), (7), (8), (9), (10),(11)

3. Improve Libido

Since oysters work as an aphrodisiac, one of the best health benefits of oysters is to encourage the libido, mainly for males.

This mainly results from the impressive amount of zinc in oysters that are even higher than an ordinary person’s daily need by 1,500 percent.

Many types of research have shown the link between the lack of zinc and sexual issues, such as erectile dysfunction or impotence.  Therefore, the provision of a great container of zinc, such as oysters, is a good way to strengthen men’s performance in the bedroom.(12), (13), (14), (15)

4. Wound Healing

The unparalleled levels of zinc in oysters result in a number of health benefits, including quicker wound healing rates, and increased immune system against numerous infections and microbes. As an essential mineral, zinc is also important for the proper growth and development of children and young adults, as well as the preservation of bodily function for people of all ages. Don’t take my word for it; read more about all of the health benefits of zinc. (16)

5. Immunity

Oysters are quite beneficial for boosting the immune system. It is certain that oysters have this quality because of their abundance of vitamin C. However, it is not all about vitamin C.

Vitamin E also takes part in the fight against harmful impacts of free radicals that might develop into cancer. Additionally, anti-inflammatory and antioxidant minerals present in oysters are active agents in containing free radicals as well. By limiting free radicals, oysters can help them stay away from mild and complicated problems. (17), (18)

6. Protein Content

Proteins found in oysters are the most essential parts of our diet. Proteins are often broken down by the body’s enzymatic activity and then reconstructed into usable human proteins in every part of the body. It confirms proper metabolic activity, tissue repair, cellular growth, muscle strength, and a wide variety of other necessary aspects of human health. The importance of protein in the diet cannot be exaggerated, and a single serving of oysters provides nearly 1/3 of the daily requirement.(19)

7. Mood Boosting

Due to the high levels of zinc found in these sea dwellers, they are known to stabilize mood. Zinc is considered an essential mineral because it is not stored by the body and needs to be consumed through diet. Research published in the American Journal of Clinical Nutrition found that increased serum blood concentrations of zinc in children were related to decreased anxiety and depression. Another research in the European Journal of Clinical Nutrition found that sufficient zinc intake was effective at reducing anger and depression in young women.

8. Energy Boosting

Oysters contain a good amount of B12 vitamins, which boost energy and turn the food we eat into energy. Recent research suggests anywhere from 15-40% of Americans don’t have sufficient levels of B12 for optimal health. Oysters also contain iron, which helps the body transport oxygen to individual cells giving an energy boost.

9. Blood Circulation and Volume

Oysters are a very impressive source of iron, with more than 90% of our daily requirements in each serving. Irons are a key component in the formation of red blood cells in the body and are the primary defense against anemia, also known as iron deficiency, which can lead to fatigue, cognitive malfunction, stomach disorders, and general muscle weakness. Also, with a fresh supply of healthy blood cells in the circulatory system, organ systems have high levels of oxygenated blood to stimulate their activity, making them function efficiently and boosting the overall metabolic rate of the body.(20)

10. Bone Health

The nutritional profile of minerals in oysters is impressive enough for us to believe in the benefits of oysters on bone health. Oysters consist of a good amount of calcium and are undeniably important to maintain strong bones.

Besides zinc, selenium, iron, and copper also have great impacts on bone durability and density. They are also related to osteoporosis prevention.(21), (22), (23), (24), (25),

11. Good for Eyes

Oysters top the list of natural sources of zinc, the mineral that ensures that the eye’s pigment is sufficiently produced in the retina. The more zinc, the stronger your eyesight, because reduced pigmentation is often associated to a reduction in the central visual field of vision.

How to Eat

• Oyster sauce is used in Vietnamese, Thai, and Chinese cuisines as a tempering while cooking noodles, vegetables and stir-fries or as a marinade.
• Oysters can be eaten on the half shell, raw, smoked, boiled, baked, fried, roasted, stewed, canned, pickled, steamed, or broiled, or used in a variety of drinks.
• They are occasionally served on edible seaweed, such as brown algae.

Other Facts

• Shells of oysters can be crushed and used as mulch in your garden.
• A Group of oysters is usually called a bed or oyster reef.
• Each oyster filters about 30 to 50 gallons of water a day.
• They have extremely strong adductor muscles to close their shells when threatened.
• Oysters have a three-chambered heart, colorless blood, and a pair of kidneys.
• Female oysters can release well in excess of 1 million eggs over the spawning season.
• Most people think that pearls are round and white; however natural pearls can be colored yellow, rose, or even black. Cultured pearls take 3-6 years to reach a commercial size and are produced by placing a polished piece of mussel shell inside the oyster.
• Chinese were probably the first to raise oysters artificially in ponds and to use their crushed shells in medicines.
• The Guinness World Record for the most oysters eaten in 3 minutes is 187 set by Norwegian Rune Naira in 2003.
• Oysters begin life as males and change to females the next season.
• Most oysters can live up to 20 years in captivity.
• Oysters breathe much like fish, using both gills and mantle.
• Oysters are “alternating hermaphrodites”, which means they can switch sexes from time to time.
• Only about one in 10,000 oysters contains a pearl.

Selection, preparation, and storage

Unlike most shellfish, oysters can have a fairly long shelf life of up to four weeks. However, their taste becomes less pleasing as they age. Oysters should be refrigerated out of water, not frozen, and in 100% humidity. Oysters stored in water under refrigeration will open, consume available oxygen, and die.

Freshly opened pearl oysters

Oysters must be consumed alive, or cooked alive. The shells of live oysters are usually tightly closed or snap shut given a slight tap. If the shell is open, the oyster is dead, and cannot be eaten safely. Cooking oysters in the shell kills the oysters and causes them to open by themselves. Traditionally, oysters that do not open have been supposed to be dead before cooking and therefore unsafe.

Side effects of oysters

Let us now view some of the side effects of eating oysters. Some major side effects of eating oysters have been stated below:

1. Shellfish poisoning

As oysters feed on plankton and help keep the marine environment clean by removing various toxins, they might gather some dangerous poisons and toxins in their shells. These toxins are produced by microscopic algae such as dinoflagellates, diatoms, and cyanobacteria and cause amnesic, paralytic, and neurotoxic syndromes called Amnesic shellfish poisoning (ASP), Diarrheal shellfish poisoning (DSP), Neurotoxic shellfish poisoning (NSP), and Paralytic shellfish poisoning (PSP).

• Amnesic shellfish poisoning is caused by domoic acid produced by diatoms. In humans, domoic acid acts as a neurotoxin and causes permanent brain damage (loss of short-term memory), and maybe deadly in severe cases.
• Diarrheal shellfish poisoning is caused by okadaic acid, which prevents de-phosphorylation of cells in the gastrointestinal system and causes diarrhea, nausea, and vomiting. It is not a life-threatening ailment and a symptom normally stops after a certain time.
• The causative agent of neurotoxic shellfish poisoning is brevetoxin (and substances similar to it). It is usually not fatal but may cause neurological symptoms such as speech problems (slurred speech, difficulty to talk). Also, abdominal pain accompanied by diarrhea, vomiting, and nausea may be present.
• Paralytic shellfish poisoning is caused by a neurotoxin called saxitoxin, which is produced by microscopic algae, such as diatoms, dinoflagellates, and cyanobacteria. It can be fatal in extreme cases however it usually causes symptoms such as abdominal pain (accompanied by nausea, vomiting, and diarrhea), burning or tingling sensations (affecting mainly lips, tongue, gums, face, arms, legs, and toes). Some other symptoms also include shortness of breath, choking feeling, and dry mouth. Cyanotoxin is produced by cyanobacteria, may accumulate in oyster shells, and can cause lethal poisoning.

2. Infection from bacteria

It is really important to know about the type of oysters. The reason behind this is that oysters obtained from certain areas can make you ill because they contain dangerous bacteria. One example of this is the Vibrio Vulnificus bacterium which is commonly found in the coastal regions and the total number of these bacteria is increasing day by day. There is a high probability that the oysters can get infected with bacteria, which can in turn infect humans when consumed. Some common side effects of eating bacteria-infected oysters include vomiting, diarrhea, fever, and skin reactions. A person can even go into a shock if not treated correctly. In general, heat can destroy bacteria. So make sure that you never eat raw oysters and only eat properly cooked oysters to avoid bacterial infection.

3. Allergic reactions

Another side effect of oysters is that they can cause food allergies. A protein present in oysters by the name of tropomyosin is responsible for causing the oyster allergy. Some major side effects caused by oysters in people who are sensitive to tropomyosin are facial swelling, skin rashes, abdominal pain, and other side effects.

4. Hemochromatosis

The iron content in oysters is quite high. A 3 ounce serving of oysters can fulfill 44% of your daily needs. Iron is important for the body but people suffering from hemochromatosis (a genetic condition that automatically increases the amount of iron in the body) shouldn’t eat oysters because they can cause dangerous side effects. Some of these side effects include lethargy, loss of hair, abdominal cramps, and changes in skin color.

5. Gastrointestinal problems

Eating oysters can also cause gastrointestinal problems caused either by toxins (see shellfish poisoning section above) or by a high content of zinc in oysters, which can cause some gastrointestinal problems. Some of the major reactions include diarrhea, abdominal cramps, and vomiting. These effects will be visible within five to six hours after consumption of oysters. But they end when the zinc levels in the body fall back to normal.

Precautions 

• The consumption of sea fish if one is trying to reduce inflammatory diseases such as heart disease.
• Farmed ones contain arsenic that leads to arsenic poisoning.
• Seafood should be cooked safely in order to prevent foodborne illness.
• Pregnant women, young children, older adults, people having lower stomach acid and compromised immune systems (HIV/AIDS, liver disease, cancer, diabetes, gastrointestinal disorders, people taking steroids, chemotherapy, or immune system) are prone to higher risk.
• It might be contaminated with bacteria such as Vibrio parahaemolyticus, Vibrio vulnificus, and other bacteria relate to land use, sewage discharges, runoff, etc. These microorganisms occur naturally in warm coastal waters which could cause even death or serious illness in individuals who are at higher risk.
• Listeria monocytogenes could cause a serious foodborne illness known as listeriosis.
• The virus Hepatitis A could survive in light cooking. So one should consume it after being properly cooked.
• Fish could have toxins that could cause illness such as ciguatoxin and scombrotoxin, or histamine poisoning.
• Sea fish is related to Scombrotoxin (histamine) which develops when fish is not kept cold enough. The symptoms develop quickly and also disappear completely within 24 hours.
• The flesh of tropical marine fishes might cause ciguatera poisoning experiencing gastrointestinal maladies that could last for several days, weakness in arms and legs, and reversal inability to differentiate between cold and hot. The symptoms could persist for weeks.
• Farmed seafood results in to increase in inflammation leading to weight gain, arthritis, and heart diseases.
• The imbalance ratio of Omega-6 and Omega-3 causes heart disease and hypertension.
• Seafood and fish in farms have polychlorinated biphenyls (PCBs), organophosphorus (OPs), organochlorine (OC), trifluralin pesticides, and hexachlorobenzene (HCB) causing diseases or even death.
• The seafood has a high content of mercury, which may lead to mercury toxicity.
• Consume it in moderate amounts. So consume it with caution or Avoid consuming it raw.
• Some people might get allergic reactions. So avoid it.
• It has a high chance of contamination.
• One should limit its intake.
• Consult the doctor by pregnant women and children before consuming it. Children and pregnant women should avoid it because the high content of mercury might cause a negative impact on the development of the nervous system of a fetus.
• Seafood or fish have purines in it which is harmful to people having purine-related problems. Excess purines result in an excess buildup of uric acid that could lead to the formation of kidney stones as well as gout.

References

Show More