Nondairy milk storage

How long is it safe to keep opened nondairy milk unrefrigerated for? I know that for dairy, it should be stored at 5C, and once it reaches room temperature, needs to be discarded. The packaging says refrigerate after opening, but I have been told that it can be kept out indefinitely “it won’t kill you”, who is correct?

Maximum 2 hours. To know more check this link: