Not all oysters can be eaten raw, and some oysters cannot be eaten raw even if they have just been fished out of the sea.

So, which oysters can be sashimied and eaten raw, and which oysters cannot be sashimied and eaten raw?

The risks of eating raw oyster sashimi mainly include three aspects: microbial pathogenic bacteria contamination, heavy metal contamination, and shellfish toxin contamination.

Oysters that can be eaten raw as sashimi are generally required to grow in first-level waters; aquatic products in second-level seas are only suitable for cooked food; third-level seas are generally only suitable for swimming, which is not allowed in countries with standardized food management.

Aquatic products are grown or caught for consumption in waters; if it is a Level 4 sea, it is not suitable for swimming. Generally, such sea areas are only suitable for docks.

Because our country is relatively weak in sea area management, offshore pollution is very serious.

In July 1997, the United States banned the import of Chinese oysters on the grounds of unequal sea area management; at the same time, the European Union also promulgated Regulation 386 to ban the import of Chinese oysters.

Microbial pathogenic contamination can be avoided by cooking, while heavy metal contamination is easily overlooked.

Oysters are filter-feeding organisms and have a relatively strong ability to accumulate heavy metals. However, conventional cooking methods cannot eliminate the hazards of heavy metals.

Shellfish toxins, like microorganisms and heavy metals, are not produced by oysters, but are caused by environmental influences.

Shellfish toxins are mainly caused by oysters ingesting some algae in polluted eutrophic seawater, resulting in the accumulation of shellfish toxins.

Shellfish toxins mainly include inflammatory shellfish toxins and diarrheal shellfish toxins. If these toxins exceed the standard, they cannot be used not only in raw food, but also in cooked food, because high temperatures cannot destroy shellfish toxins.

Some domestic oysters claim to be sashimied and eaten raw, but in fact they are purified oysters.

It is to send oysters that are contaminated by microbial pathogens, heavy metals, and shellfish toxins into clean and closed pools for breeding until they reach the specified indicators before entering the market.

Even after purification, there are still significant risks.