Can clams that died after being left out overnight still be eaten?

It is not recommended to eat clams that have died after being left overnight. Once clams die, bacteria multiply rapidly inside their bodies and produce toxins. Even thorough cooking cannot completely eliminate these toxins, making consumption likely to cause gastrointestinal discomfort or even poisoning. If severe vomiting, diarrhea, or dizziness and weakness occur after accidental consumption, prompt medical attention is advised.

Clams are a type of shellfish that rely on oxygen in water to survive. After death, their body cells decompose quickly, allowing bacteria in the intestines to multiply extensively and spread throughout the tissue. Leaving them overnight allows bacterial levels to reach dangerous concentrations, while also producing heat-resistant toxic substances such as histamine, which cannot be fully destroyed by normal cooking methods.

Live, fresh clams have firm, elastic flesh. After death, the meat quickly becomes soft, slimy, and develops an unpleasant odor. Even if there are no obvious signs of spoilage, the clam may already be contaminated with bacteria. Consumption may lead to symptoms of acute gastroenteritis such as abdominal pain, diarrhea, and nausea, with more severe reactions possible in individuals with sensitive constitutions.

When purchasing clams, choose live, active specimens. Place them in clean water temporarily to expel sand, and consume them on the same day of purchase. If short-term storage is necessary, keep them in a cool, moist environment with adequate ventilation—avoid sealed, stuffy, or warm conditions. Before eating, wash thoroughly and ensure they are fully cooked. Never consume any shellfish that has died.