Storing food in the original can in the refrigerator can be safe under certain conditions, but it's not recommended for several reasons:
Hygiene: The top of the can may come in contact with the contents, and cans are not designed to be resealed. Bacteria from the can's surface or from the food inside could contaminate each other.
Taste and Quality: Storing food in an open can can affect its taste and quality. The can's metal can impart a metallic taste to the food, and the food's flavor and texture may deteriorate faster.
Safety: If the can has sharp edges after being opened, it could be a safety hazard when handling it in the fridge.
Leaching: Some cans may have a lining, and acidic or highly salted foods might cause the lining to leach into the food, which is not ideal for health reasons.
For these reasons, it's better to transfer any leftover food from an opened can into a clean, airtight container suitable for refrigeration. This way, you can preserve the food's quality, reduce contamination risks, and ensure its safety for a longer period.
If you plan to use canned food and store the leftovers, choose cans with easy-open lids or transfer the contents to an appropriate container before refrigerating. Remember to always follow the manufacturer's recommendations for storing and consuming their products.