How can pasteurized milk last 7 days?
I would rather think about regulatory differences instead of biological ones. (Edit, as also Rory M highlighted in a comment)

Extended shelf life can be obtained through microbial ultrafiltration. However in Europe, ultrafiltration labelling is not mandatory, so it is difficult to distinguish if a milk product was simply pasteurized or also ultrafiltrated. The converse case, biologically speaking, two milk products could be generally the same but one country could be more stricter than the other on shelf-life legislation. (The shelf-life relates more to the unsuitability for sale rather than for consumption).