Sweet potatoes contain a variety of bacteria, including lactic acid bacteria, which are responsible for the fermentation process that gives sweet potatoes their unique flavor. Additionally, sweet potatoes can contain a range of other bacteria, such as Bacillus subtilis and Enterobacter cloacae. These bacteria are typically found in soil and water sources where sweet potatoes are grown. While these bacteria may not be beneficial to humans in large quantities, they can help to break down organic matter and improve the fertility of the soil in which sweet potatoes are grown.