According to the CDC, there are at least 40,000 proven cases of salmonellosis in the United States each year. Although there are over 2,400 of different subspecies (serovars) of salmonella, since 1990, one serovar, Salmonella Enteritidis (SE) has been the primary cause of salmonellosis around the world. In 80 percent of cases, eggs are the source of the infection.
Common Symptoms of SE
In most cases, SE produces mild, self-limited gastroenteritis with classic symptoms of fever, stomach cramps, nausea, vomiting and diarrhea. Symptoms begin 12 to 72 hours after ingestion of the contaminated food or beverage and persist for four to seven days. Young children, the elderly and people with chronic medical problems are the most likely to be hospitalized, usually for dehydration.
Antibiotic treatment is required in less than 2 percent of cases. Salmonellosis usually occurs as isolated cases in individuals rather than as an outbreak where a number of people are affected. In healthy adults this makes it difficult to distinguish SE from viral gastroenteritis, and the number of reported cases is probably much lower than the actual number of cases.
Uncommon Symptoms of SE
In rare cases, SE escapes the intestine to enter the bloodstream. Bloodstream infection may itself be fatal and can produce long-term complications when SE leaves the bloodstream to infect other areas of the body. Long-term complications of SE infections include infection of the heart valves and lining of the heart (endocarditis), the bone (osteomyelitis), brain abcess and Reiter's Syndrome, an autoimmune disease that produces chronic joint pain, eye irritation and urination problems. These complications rarely occur in healthy adults. Almost all cases occur in immunocompromised people (those with AIDS, cancer and sickle cell anemia) or people with multiple medical problems.
Prevention
Since the 1990s, most restaurants have added warnings about the dangers of undercooked eggs to their menus and substituted flash pasteurized egg products in other applications. At home, eggs should be cooked until they are no longer runny. Flash pasteurized fresh raw eggs and pasteurized powdered eggs should be used in recipes like ice cream, egg nog and icings, where the eggs will not be cooked. Always discard eggs with broken or dirty shells. Wash your hand, utensils and cooking surfaces after working with eggs or any poultry product. Eat or refrigerate eggs promptly after cooking. Foods kept warm for more than two hours should be discarded. Be especially careful when you are preparing food for children, the elderly, and people with other medical problems.
References
- CDC: Salmonella Enteritidis
- United States Department of Agriculture Food Safety Research Information Office: A Focus on Salmonella
- Foodborne Pathogens and Disease. Overview and Summary of the Food Safety and Inspection Service Risk Assessment for Salmonella Enteritidis in Shell Eggs, Winter 2006.
