Use a pressure canner, 250 degrees for 15 minutes, 15 psi, nothing survives that.
Or adjust the wort to have a pH below 4.6 because growth of Clostridium botulinum and the production of its toxin is inhibited below a pH of 4.6.
I would choose the pressure canner as the most conservative method. I'd hate to find out the hard way that my pH meter was reading high.