The U.S. Centers for Disease Control still identifies infection with salmonella bacteria from eggs as an important public health problem in both the United States and Europe. Some 118,000 cases a year stem from Salmonella enteritidis found in eggs. Symptoms include fever, abdominal cramps, nausea, diarrhea, and vomiting that begin 12 to 72 hours after eating foods made with contaminated eggs. The illness can last four to seven days. Although most people recover without antibiotic treatment, those who develop severe diarrhea may need hospitalization. The illness tends to be most serious in the elderly, infants, and those with impaired immune systems.
The bacteria get into the eggs even before the shells are formed by invading the ovaries of healthy-appearing hens. You can't tell from looking at an egg whether or not it is contaminated, but you can destroy the bacteria and prevent illness with proper handling and cooking of eggs, which means:
- Buy eggs only from a refrigerated case and store them in the refrigerator as soon as you get them home. Use eggs within three weeks of purchase.
- Cook eggs until both yolk and white are firm. Make sure all foods containing eggs are cooked to 160 degrees.
- Serve cooked eggs and dishes containing eggs immediately after cooking. Refrigerate hard-boiled eggs after two hours (whether they're still in the shell or have been peeled), and refrigerate all foods containing eggs. Eat all foods containing cooked eggs within four days.
- For Caesar salad dressing, homemade ice cream, and other recipes that call for raw eggs, use only pasteurized eggs that have been heat treated to destroy salmonella. The heat kills the bacteria but isn't high enough to cook the eggs. Cartons containing these eggs should be clearly marked.
Considering all the eggs consumed in the United States annually, the threat of illness from contaminated eggs must be small. I don't recommend giving up eggs to avoid salmonella infection. Egg whites are a great source of protein, and the yolks contain an astonishing array of essential fatty acids, vitamins and minerals, including vitamins A,D,E and K, plus iron. You can also get eggs fortified with omega-3 fatty acids. I prefer organically produced eggs from free-range chickens. But whatever eggs you buy, be sure to observe the cooking and handling precautions outlined above.
Andrew Weil, M.D.