I don't know whether this will help, but for Grapevine explants, I always used 70% ethanol for 30-60 sec, then rinse with sterile water 2-3 times. After that, I treated with bleach (not too long, 30-60 seconds as well). I always wash with steril water at least 3 times after this.
Usually, for leaves or shoots, I only had approximately 10% of contamination.