Are Raw Oysters Safe To Eat?

Oyster is the name that represents various families of animal that belong to the family of salt-water bivalve Mollusca. The valves of some of the species are usually very calcified, and may not be regular in shape.  Oysters are edible animals, and they can be either eaten raw or cooked before eating. In addition, some oysters are harvested particularly because of their pearls, which is made inside their mantle. Also, the shells of some oysters are translucent, which makes them useful for aesthetic purposes.

Type Of Oysters

True oysters: The oysters that belong to this family are edible. Examples of these oysters are Belon, eastern, Olympia, and Pacific oyster.

Pearl oysters: The majority of the mollusks that have shells are capable of producing pearls, although, the majority of them are not too valuable. Pearl oysters are not close to true oysters. The Pinctada maxima are about the size of a plate. It’s a popular misconception that all oysters produce a pearl, however, only about three out of three tons of oyster actually do produce pearls. Some farmers have found a way around this, they culture pearls by placing the nucleus inside an oyster, and leaving it to a couple of years. They harvest the oysters and sell in the market, however, this kind of pearls produced are not as valuable as the natural ones.

How Are Oysters Cultivated?

Oysters can be harvested in many ways. This includes by hand picking, especially when picking them from waters that are not deep. In some zones, scallop dredge is used. They are an efficient way of collecting oysters in a large sum, at a time, although they do damage the seabed. The use of the scallop dredge has been stopped in some areas, due to its damage and disruption of the sea ecosystem. There are two ways of cultivating oysters, these are release and bagging. The oysters are extracted from water and then brought onshore to be cultivated. The oysters get to fix themselves to a substrate, where they grow and in turn produce seed oysters”. The oysters are then transferred to a water body, where they would grow and mature. On the other hand, the release method is done by spreading the spat throughout the already existing beds. This is to give the oysters the chance to grow naturally.

What’s The Impact Of Humans On Oysters?

Human activities on oysters have been largely negative so far. For instance, it was recorded that pollutions below the water to make them close their shells, especially when they are exposed to sounds of low frequencies. Also, the sounds of vessels, ships, and submarines moving in the water all affect the activities of the oysters. Oysters make use of the water waves and movements to determine their circadian rhythm, so any major alterations in these activities would hugely affect the oysters.

Oysters Can Also Be Consumed As Food

Humans started consuming oysters many centuries ago, probably before history was recorded. The evidence of this is the oyster remnants discovered in most parts of the world. They were consumed as food, especially in areas with water bodies. In addition, people cultivated oyster, so they can be eaten and sold off as food. It had an entire industry. Although human activities and natural disasters have put a decline in their supplies, however, they are still a major delicacy in oyster-themed festivals and celebrations.

There is a common practice which is called depuration. This is a process by which fecal matter and waste are removed from the oysters before they are sold to consumers. This is because most people do eat oysters raw. The process of depuration also involves draining the oysters of the water they were harvested in and washing them with sterilized water.

Nutritional Importance Of Oysters

Oysters are a rich source of microelements such as iron, calcium, and zinc. The zinc improves the body immune system and helps the body in the removal of skin conditions such as acne, eczema and body rashes. In addition to this, they also contain vitamins such as vitamin A, cyanocobalamin and protein. Some people also hold the notion that oysters are good aphrodisiacs, primarily because they contain some amino acids that can improve the sex hormone levels in the body.

How To Prepare And Store Oysters

It has been observed that the older the oysters, the less desirable their taste becomes.  Oysters are meant to be eaten or cooked while they are still alive. A closed oyster shell means that it’s still alive, while an open shell shows that the oyster is dead, and therefore should not be eaten.

How To Eat Oysters

Oysters are meant to be eaten or cooked while they are still alive. A closed oyster shell means that it’s still alive, while an open shell shows that the oyster is dead, and therefore should not be eaten. They can be consumed raw, while still alive, boiled, baked, canned and even roasted. To consume oyster is as easy as just opening the shell and digesting the contents.

Risks Of Eating Oysters

Chefs and biologists have suggested that the best way to consume oysters, is to eat them raw. However, oysters naturally filter the medium in which they find themselves. According to studies, oysters filter about 45 gallons of water daily. As an illustration, oysters that grew up in a sea ocean would constantly sieve and filter the water that they come across. This exposes to a lot of microorganisms, so eating this kind of oyster would predispose the consumers to infections. The people affected most by this, are the people with a weak immune system, or people who are immune compromised. This may lead to complications such as septicemia, and eventually death, if not managed well.

What Oysters Are Safe for Eating?

As said earlier, people with the weak immune system should desist from consuming oysters, as they often do have a lot of microorganisms in their valves, largely due to their filtering behavior. Overall, consumers are advised to pay more attention, and possibly ask where the oysters were gotten from. In addition, consumers should also learn a thing or two about the oysters they are eating.

References

Holliday, J., Allan, G., Frances, J. and Diver, L. (1993). Evaluation of commercially-used collectors for Sydney rock oysters, Saccostrea commercialis and Pacific oysters, Crassostrea gigas. Aquacultural Engineering, 12(2), pp.63-79.

Oysters and typhoid fever. (1895). Public Health, 8, pp.9-10.

Pavia, A. (1987). Cholera from raw oysters shipped interstate. JAMA: The Journal of the American Medical Association, 258(17), pp.2374b-2374.

Scientific Opinion on Norovirus (NoV) in oysters: methods, limits and control options. (2012). EFSA Journal, 10(1), p.2500.