Within the past decade, major strides were made in our understanding of foodborne pathogens, with four relatively unknown bacteria identified as important causes of food-related illness. Campylobacter jejuni has risen from obscurity as a veterinary pathogen to recognition as the leading cause of acute bacterial diarrhea in many countries. Vibrio vulnificus has been identified as a cause of severe seafood-related illnesses among individuals with liver dysfunction, with a mortality rate of >40%. Listeria monocytogenes is widely distributed in nature and unprocessed foods, and causes severe illness, principally in specific populations. Fortunately, listeriosis is relatively uncommon in the USA, with about 1700 cases occurring annually. Escherichia coli O157:H7 was identified as a pathogen in 1982 as a cause of hemorrhagic colitis (bloody diarrhea) and hemolytic uremic syndrome (kidney failure). Illnesses are often associated with eating undercooked ground beef. Dairy cattle are a reservoir of the organism. All of these bacteria are uniquely different, but proper cooking and hygienic handling of (cooked) foods before consumption would greatly reduce, if not eliminate, the risk of foodborne illness by these organisms.