The concept of ownership can be subjective and context-dependent. In a shared refrigerator at work or school, the general expectation is that items are not meant to be stored there indefinitely, especially if they are perishable or taking up valuable space.
If you left an item in the shared refrigerator for an extended period, and it hasn't been touched or claimed by anyone else during that time, it's possible that others might assume it has been abandoned or forgotten. In such cases, it could be considered courteous to remove the item to free up space for others to use.
If the item holds significant value or has sentimental importance, it's always best to communicate with others in the shared space before removing it, in case someone else was respecting your belongings and keeping it safe for you.
To avoid potential misunderstandings, it's a good idea to label your items with your name and date when placing them in shared spaces. Additionally, be mindful of how long items are kept in shared areas and make an effort to retrieve them in a reasonable timeframe.