All of the McD's sandwiches showed signs of decomposition. Even the Big Mac began to rot to some degree after several weeks.
However, the fries appeared to resist rotting for up to ten weeks! What's in them?
Since the OP reported on a new GMO in the potatoes that were going to be used by McD's, I wondered just how many unnatural ingredients the new fries will contain.
And I, too, haven't eaten at McD's since the early 1970s! But my "boycott" was due originally to McD's approach to advertising and Ray Kroc's purchase of the San Diego Padres baseball team (1974). I was living in San Diego at this time when this happened--
He proved that class doesn't come from a wallet.