CRJ FLT CREW AT FL320 RPTS ENCOUNTERING WAKE TURB FROM AN OPPOSITE DIRECTION B747-400 AT FL330.

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WHILE LEVEL AT FL320; ON J107 S OF MLF; WE ENCOUNTERED MODERATE TURB CAUSED BY AN ACFT PASSING DIRECTLY OVERHEAD. THE RIDE PRIOR TO THE EVENT WAS SMOOTH. THE CONDITIONS AT FL320 WERE IMC; HOWEVER; THE SKY ABOVE WAS VISIBLE. TCAS INDICATED TFC AT OUR 12 O'CLOCK POSITION AT FL330 APCHING ON J9/J107; THE EXACT RECIPROCAL OF OUR COURSE. SLC ARTCC DID NOT IDENTIFY THE TFC. WE MONITORED THE TCAS AND ACQUIRED A VISUAL OF THE TFC AS IT PASSED OVERHEAD. TO OUR SURPRISE IT WAS A B747-400. WITHIN SECONDS OF THE PASS; WE ENCOUNTERED ITS WAKE AND EXPERIENCED AT LEAST MODERATE TURB FOR 1 TO 2 MINS IN DURATION. I NOTIFIED ATC OF THE EVENT; THE CTLR DID NOT SEEM CONCERNED. PRIOR TO THE ENCOUNTER; THE FLT ATTENDANT WAS CONDUCTING HER CABIN SVC AND THE SEAT BELT SIGN WAS OFF. FORTUNATELY; THE FLT ATTENDANT AND PAX SURVIVED THE UNEXPECTED ROUGH RIDE WITH JUST A FEW SPILLED DRINKS. IN TRAIL OF THE B747 WAS ANOTHER B747-400 AT FL330. WE DEVIATED E OF COURSE AND AVOIDED PERHAPS A SIMILAR EXPERIENCE. WE REQUESTED THE TYPE OF ACFT APCHING BEFORE ATC RPTED THAT TFC. I UNDERSTAND THAT IT IS MY RESPONSIBILITY; ULTIMATELY; TO SEE AND AVOID OTHER TFC WHEN PRACTICAL; THAT I COULD HAVE REQUESTED A TFC RPT FROM ATC. HOWEVER; WITH RVSM IN PRACTICE; ATC SHOULD BE REQUIRED TO RPT A POSSIBLE WAKE ENCOUNTER SO PLTS CAN ALERT THE CABIN OCCUPANTS AND DEVIATE AS NECESSARY TO AVOID THE WAKE. WE WERE VERY LUCKY THAT ALL PAX AND CREW WERE UNHARMED.