Not entirely true. I spent a month in Banska Bystrica Slovakia working out of the Sliac airport and although we enjoyed the local cuisine a lot, there were a couple of times we had to work late and sent somebody to a McD's for double quarter pounders...and they tasted just like they do here in the States.
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Was that McD's close to any kind of US military base or installation? If yes then it's possible that store gets its beef from the US in order to suit the American taste.