E. Coli is primarily found in beef. The most dangerous form of E. coli, 0157:h7, is particularly dangerous for children. The elderly, children, and those with compromised immune systems are most at risk for all food-borne illnesses. Salmonella can be found in beef, pork or poultry, but is most commonly found in poultry. Listeria is usually found in packaged foods, such as lunch meats, soft cheeses, and other processed foods. Fruits and vegetables can also be contaminated with these pathogens, usually from contaminated water used to irrigate or process them. Listeria is particularly dangerous for pregnant women, because it can cause miscarriages. Heat is the best weapon consumers have against food borne illness. The USDA has guidelines for proper cooking temperatures.