Wednesday, April 17, 1996 | 11:59 a.m.
"This is a new phenomenon in Utah. It's early in the game," said Jeremy Sobel, medical epidemiologist at the federal Centers for Disease Control and Prevention in Atlanta. "There are specific things that can be done that are proven effective in controlling this infection."
The culprit is a subtype of Salmonella Enteritidis (SE), which in the late 1970s was blamed for a rising number of salmonellosis cases. The subtype, known as phage type 4, is associated with human disease wherever it is found.
The bacteria cause high fever, headache, abdominal pain, diarrhea and nausea. Most victims recover within a week, but dehydration can be severe in infants, the elderly and those with impaired immune systems.
Eggs are the most common source of SE.
Other strains of Salmonella commonly are spread through fecal material, which can contaminate the outside of a chicken carcass or an egg. However, SE is able to infect the ovaries of hens and invade the egg as it forms.
Not every egg laid by an infected chicken will contain the bacteria.
About one of every 235,000 eggs is contaminated, said Donald McNamara, executive director of the Egg Nutrition Center in Washington, D.C.
"It's very hard to find and this is what complicates life. The numbers are small," McNamara told The Salt Lake Tribune.
If just one infected egg is mixed with clean eggs, the whole batch can be contaminated. If the pooled eggs are not cooked to a temperature that kills the bacteria, or come in contact with uncooked foods, people can become sick.
Utah health officials became alarmed last year when the number of SE cases jumped to 129 after a four-year average of 34 cases.
"We found no common sources, nothing significant when the number of cases began going up," said Craig Nichols, state epidemiologist.
He recruited Sobel, who arrived in Utah in late January. For the next two months, Sobel, Nichols and a staff interviewed salmonellosis victims and matched them with well people.
"What we found is that you were more likely to become ill if you'd eaten at a restaurant and the only meal that was significant was dinner," Nichols said.
Eggs were sampled, but none contained SE. Finally, an outbreak among Utahns who ate at a Nevada restaurant that pooled 240 eggs every day provided the needed link.
"What we saw in this restaurant is that workers would handle an egg batter coating and without washing their hands would pick up lettuce and garnishes to put on hamburgers and other sandwiches," Nichols said.
Investigators then focused on 25 restaurants where patrons had become ill and looked specifically for possible contamination with pooled eggs. The restaurants all had sources of potential contamination.
Investigators traced egg shipping records but were unable to determine the sources of the contaminated eggs.
The investigation is prompting the health department to revise its food code to prohibit the use of pooled raw eggs for foods that are not cooked, such as salad dressings, or foods that may sit for long periods, such as batters.
Instead, pasteurized eggs should be used. Consumers should know that eating raw or lightly cooked eggs could be risky.
"If we can get everybody involved at once on this we can reduce the number of cases and prevent some cases," Nichols said.
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