Which shellfish is noted for being most likely to cause illness?

Oysters are commonly recognized as the shellfish most likely to cause illness, primarily due to their ability to accumulate harmful bacteria, viruses, and toxins from the water in which they live. One of the most significant risks associated with oysters is their association with Vibrio bacteria, particularly Vibrio parahaemolyticus and Vibrio vulnificus, which can lead to serious gastrointestinal illnesses. Oysters are often consumed raw, which increases the risk of foodborne illness because the cooking process that would normally eliminate harmful pathogens is bypassed.

Additionally, oysters can also bioaccumulate pathogens such as norovirus, which is known for causing outbreaks, especially in settings where they are served raw or lightly cooked. Their habitat in marine waters, especially during warm months, further contributes to the risk since bacteria tend to proliferate in warmer conditions.

While clams, mussels, and cockles can also cause illness, especially if harvested from polluted waters, oysters' prevalence in raw seafood consumption and their specific association with serious pathogens make them the shellfish of greatest concern when it comes to food safety and foodborne illnesses.