Can kelp be eaten the next day after being left overnight?

Generally speaking, cooked kelp can be consumed the next day if it is promptly cooled, sealed, and refrigerated, and then thoroughly reheated. However, kelp that was undercooked, stored at room temperature, or improperly sealed during refrigeration should not be eaten the next day. Detailed explanations are as follows:

If the kelp has been thoroughly cooked, the leftovers should be promptly cooled to room temperature, stored in a clean, sealed container, and refrigerated. Reheating thoroughly before consumption the next day can kill any small amounts of bacteria that may have developed, making it safe to eat without causing discomfort. This storage method slows bacterial growth, better preserves the kelp's quality, and prevents excessive nutrient loss.

If the kelp was undercooked or left at room temperature for a prolonged period after cooking, pathogenic bacteria such as Vibrio parahaemolyticus may easily proliferate. Even if subsequently refrigerated, the bacteria may have already produced toxins, which are difficult to eliminate completely through reheating. If the kelp was not sealed properly during refrigeration, it may become contaminated with bacteria from other foods in the refrigerator or absorb odors, potentially leading to gastrointestinal issues such as abdominal pain and diarrhea after consumption.

Before consuming leftover kelp, check its condition. If there is an unusual odor, sliminess, or abnormal texture, discard it directly. Ensure it is thoroughly reheated before eating—never consume it cold. It is recommended to refrigerate leftover kelp for no more than 24 hours to avoid increased safety risks associated with long-term storage.