B757-200
Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Wake Vortex Encounter
General Physical Injury / Incapacitation
Environment - Non Weather Related; Procedure
Experienced wake turbulence about 45 minutes into the flight while level at FL350 in mostly smooth flight conditions and seatbelt sign illuminated. It lasted perhaps 1 second; but most certainly got our attention. I knew the flight attendants (FAs) were preparing to serve the passengers and most importantly were not strapped in. An immediate call to check on them revealed that they were OK including the passengers. However one of the FAs had steam from the oven touch the skin on one of her arms. I inquired a few times during and after the flight; but every time she advised me she was fine. We advised ATC and were told that a B747 had crossed our path about 2 minutes earlier at the same altitude.Crossed flight path of B747. We were not advised of the crossing traffic and the vortex of the B747 had not yet descended sufficiently below our flight path. Weather conditions off and on IMC.More separation. ATC advice of crossing traffic.
B757-200 Captain reported encountering wake turbulence at FL350 when the crossed the flight path of a B747 operating at the same altitude.