Romaine lettuce contaminated by E. coli bacteria. Hummus with tahini tainted by salmonella. Ready-to-eat ham and pork products rife with listeria. Multistate outbreaks such as these, which occurred in the past two months, have contributed to the 48 million cases of food poisoning — affecting about 1 in 6 residents — that develop each year in the United States, according to the Centers for Disease Control and Prevention. Consuming food or drink contaminated by bacteria, viruses, parasites or other toxins can lead to one of more than 250 foodborne diseases, mostly infections. Typical symptoms may include nausea, vomiting, stomach pain, diarrhea and sometimes fever, lasting from a few hours to several days. Most people have mild cases and recover without treatment, but about 128,000 U.S. residents are hospitalized each year because of food poisoning, and 3,000 people die of it. Some people can experience long-term effects, including damage to their brain, nerves or kidneys. Contamination of food can stem from a problem at any point in the food chain, from when a food is grown, harvested or produced, to when it is shipped and stored to when it is prepared for eating. To prevent food poisoning at home, start by making sure your hands and all cooking utensils and surfaces are washed well and often. The transfer of harmful organisms from one surface or food to another — called cross contamination — is often the cause of food poisoning. Raw, ready-to-eat foods, such as lettuce and other produce, are especially vulnerable because harmful organisms will not be destroyed by cooking. A thermometer can help ensure that food is cooked at an adequate temperature to kill germs that could cause food poisoning. For instance, food safety experts say the internal temperature should be 160 degrees for ground beef, 165 degrees for chicken and 145 degrees for steaks, roasts and pork chops

— Linda Searing