She timed 25.46 seconds, to lower Sweden’s Anna Karin Kammerling’s previous world mark of 25.57 set in July 2002 in Berlin.
The 29-year-old Alshammar as a result wins a car which is displayed at each of the Mare Nostrum meets and is valued at 380,000 kronor ($53,000).
The Swedish swimmer has had an exceptional year, winning the world title over the distance in Melbourne in March and also claiming silver in the 50m freestyle.
