Backermatic immersion thermostat

vcl

I recently had to change the thermostat on my immersion heater.We were supplied with a BMST7 this is supplied with the now standard blob of silicone to prevent or discourage adjustment. The only thing is that as we have Economy 7 heating and hot water, a 60 degree setting is not high enough to give us a full days hot water without using the boost which is massively expensive. To raise the temperature to 65 degrees, do I simply remove the silicone and reset. As a matter if interest, I read on a one site that 60 degrees was the absolute minimum temperature to kill bacteria within the tank. True or false?