In fact, the majority of these bacterial cells will in fact die off, but some may actually survive. And when they pass into the small intestine, we know that in the small intestine the PH changes from acidic to basic. So in the stomach it's around two but in a small intestine it's around 8.5. And this is the perfect PH for these bacterial cells to actually grow, thrive and ultimately be able to infect the cells of our body. So what types of cells do these actually infect? Well, it's the intestinal cells, the epithelial cells found in that small intestine.