Greetings, keeper of Sheldon. I have noticed a couple concerning, (to me) issues in regard to Sheldon. Please read the stickies at the Russian section concerning substrate and food.
Those pellets are a poor substrate choice, and corn is not a good food choice.
And above all else, welcome to the tortoiseforum.
Even as a treat, corn isn't the best. You can feed the ears of it, but that's about it. A good "treat" would be a small amount of apple, once a month or so. Or even some aloe vera plant.