Foodborne invasive infection stems from consuming food or water with viable pathogens;  their growth in the food isn't always required.  Live pathogen cells must survive stomach acid, enter the intestines, adhere to epithelial cells, penetrate the membrane, multiply, and produce toxins. This leads to symptoms after an incubation period. Enteric symptoms (abdominal pain, diarrhea, nausea, vomiting, fever) are caused by pathogens like Salmonella and Shigella, while nonenteric symptoms (often including fever) arise from pathogens invading deeper tissues, exemplified by Listeria and enterohemorrhagic E. coli.  The chapter focuses on important bacterial invasive infections, classifying them by causative bacteria, disease significance, pathogen characteristics, food sources, toxin type, symptoms, and prevention strategies.