Presents for Hungry Times : Eggs: A Season for Caution
Two separate outbreaks of salmonellosis in Los Angeles County in the past year have been linked to contaminated raw eggs, according to an investigation by local health officials.
The timing of the report, which appeared in the current issue of the county’s Public Health Letter, is significant because raw and lightly cooked eggs are often consumed during the holidays--in eggnog drinks, sauces and desserts.
A particular strain of bacteria-- Salmonella enteritidis-- was isolated from the food poisoning victims in both episodes. None of the infections resulted in fatalities, but at least nine people were hospitalized.
S. enteritidis, widely associated with raw or undercooked eggs, has been rapidly increasing in recent years. However, most of the cases have been in the Eastern United States, where federal officials have been unable to eliminate the presence of the contaminant from the region’s egg-laying flocks. The problem is intractable because the yolk becomes infected before a shell is even formed in the bird’s ova duct. This means an otherwise clean, uncracked egg may harbor the S. enteritidis without any outward signs.
Despite the outbreaks, industry representatives maintain that California’s record in this area is exemplary and that no S. enteritidis infections have resulted from eggs produced in this state.
“To the best of my knowledge, there has never been a Salmonella enteritidis outbreak linked to California fresh eggs, and I hold that position now as well,” said Robert Pierre, president of the California Egg Commission in Upland.
Thirty-six people became ill, and nine were hospitalized, in the first L.A. County outbreak because cake frosting, prepared by a commercial bakery, was suspected of harboring S. enteritidis. Cakes with the suspect frosting were consumed by 95% of those reporting the illness, an extremely high infection rate.
No product recall was initiated because county health officials did not identify probable causes of contamination until weeks after the illnesses first appeared. Infections had also subsided in the interim. And during an inspection, the contaminant was not found in the bakery (the name of which was not released) or among its workers.
Several unsanitary manufacturing practices were identified at the facility and considered the probable contamination source. The company was ordered by health inspectors to correct the deficiencies.
According to county investigators, “The most likely vehicle for this S. enteritidis outbreak was contaminated non-dairy whipped cream. This product could have been cross-contaminated by use of improperly cleaned utensils, bowls and/or machines used to prepare the whipped cream frosting (after these same items prepared) batter that contained the fresh, raw eggs.” (Bacteria that may have been present in the batter were destroyed during the baking process. The frosting was not baked or sufficiently heated.)
The second, more recent, case involved 29 illnesses at a halfway home for boys where a banana pudding was the implicated dish. Again, poor handling practices were cited.
“The pudding may have been cross-contaminated by a large mixing bowl used first to scramble manually cracked fresh Grade AA eggs, which were pooled and stored overnight in the refrigerator, and then to prepare the instant pudding mixture later that morning,” according to the county report of the incident.
The county’s Public Health Letter reported that “California-produced fresh whole eggs” were being used by the commercial bakery during the first outbreak. In the halfway house, a combination of California and out-of-state eggs were used.
Shirley L. Fannin MD, the county’s director of disease control programs, said that the eggs’ origin should not have been mentioned in the final report because their source could not be stated “absolutely.” In order for health officials to have made a definitive link, an extensive trace of product and suppliers would be required, and that was not done after either outbreak.
The lack of this so-called trace is the reason California egg industry representatives continue to maintain that their products are without fault.
“One instance of improper food handling at any of the 69,000 food service establishments in California or by one of their 785,000 employees could create havoc whether eggs are innocent or not,” the egg commission’s Pierre said. “For example, the bakery in South Los Angeles County had been practicing bad food safety procedures and eggs were not implicated in that outbreak. In the boys’ home, the handlers did not properly wash a mixer, and that (episode) couldn’t be traced back to eggs.”
Pierre said his group is spending substantial time and money to help educate the food service industry and consumers to do a better job of handling eggs.
Fannin agreed that the emphasis should also be on preventing future outbreaks, but said that publicizing such incidents assists the medical community in becoming aware of contamination sources when treating patients suspected of food poisoning.
“Unless the California egg producers could say that there are such things as flocks with zero salmonella present then there is a certain inevitability that--if you look for the bacteria--you will find it,” Fannin said. “I don’t think they should be too hypersensitive about it . . . . My feeling is that California eggs or flocks have been less contaminated with salmonella than in other parts of the country. But it is not zero.”
Other sources of potential Salmonella enteritidis bacteria are raw chicken or other infected humans. In 1990, the Centers for Disease Control in Atlanta called the “emergence of grade A eggs as a major source of Salmonella enteritidis infections,” or more likely to carry the infectious bacteria than other vehicles. Symptoms includes nausea, abdominal pains, fever and vomiting. The infection can be fatal in high-risk individuals such as infants, elderly, pregnant women and those with compromised immune systems such as cancer or AIDS patients.
Salmonella bacteria are the leading cause of food-borne illnesses in this country. According to the CDC, there were 48,603 reported cases of Salmonellosis in 1990, caused by numerous infectious strains of salmonella including S. enteritidis. The actual figure, according to epidemiologists, is between 10 to 100 times greater than the illnesses formally diagnosed, or as many as four million annually. (In particular, there were 49 outbreaks of S . enteritidis in 1990 involving 1,646 illnesses, according to the CDC.)
There are several guidelines consumers can follow to counter potential salmonella contamination:
* Do not consume raw or undercooked eggs.
* While baking kills any bacteria that may be present, do not eat raw cookie, cake or bread dough that contains raw eggs.
* Do not prepare eggnog, Hollandaise sauce or mousse with raw eggs. Options: Commercial eggnog prepared with pasteurized eggs, home-made eggnog made with egg substitutes that have been pasteurized or a recipe that calls for heating eggs to a temperature that is sufficient to kill bacteria. Note: Adding alcohol to eggnog made with uncooked eggs does not destroy bacteria that may be present.
* Only purchase eggs that have been refrigerated in the market. Always refrigerate eggs at home.
* Use soap and hot water to wash and sanitize containers, utensils, cutting surfaces and hands that come in contact with raw eggs--both shell and liquid.
* Use only Grade A or better eggs. Avoid eggs that are cracked or leaking.
* Leave eggs in their original carton and store them in the main section of the refrigerator, not the egg section in the door where the temperature is usually higher.