Can a person get Mono from sharing a bite of food?

I started work at this secondhand bookstore on Thursday, and one of my friends who works there (I've known him for over two years) asked me if I wanted to try the Chinese food he'd brought for lunch. I said yes, and used the chopsticks after he'd used them. I freaked (partially because my Poli Sci professor had gone off on a rant about my generation having done nothing but drive the STI rate up in my 3:30 class, so that was still in the forefront of my mind), and asked him afterwards if he had any STDs (or STIs, technically), and he said that he was clean. Maybe it's just my overactive mind, and I'm assuming that when he said he was clean of all STIs, he meant Mono as well, but I was just wondering if it was possible for a person to get Mono from sharing "a bite" of food if the person said that he was clean. He's been married for six years, by the way, if that helps.