Originally Posted by vklvodoi

how long can you keep the pero burgers/shakes? are they 1 day only like the raw ones?

There is a note at the end of the event banner that reads "Note: Pero Shakes & Pero Burgers gathered during Gambit 9 will expire at the beginning of the next PeroPero Event!", which seems to indicate that they moved back to the old items. I'll probably be frustrated this time tomorrow when I see they have disappeared, but until then I remain hopeful.