We’ve never added lemon juice. Besides, dishes that use canned tomatoes usually require more than 10 minutes of cooking anyway. Always cook anything canned over 10 minutes and watch for bulging lids or a lack of vacuum when opening.
If a canned good develops botulism cooking will not help. It's not the botulinum bacteria that will kill you it's the botulinum toxin that the bacteria create and heat does not destroy those toxins.