Canned food is mainly sterilized (to remove existing bacteria) and sealed (to prevent new bacterial infections) at high temperatures and pressures to achieve long-term (relative) storage time. As for preservatives, they generally exist and play a role in chemical (drug) protection, which can lengthen the storage cycle, but the general dosage and dosage are in line with the current food safety requirements, and the general health damage to the human body is minimal and negligible.