As in the great tainted milk scare of 1985, Chicagoans once again have been frightened by scenes of people whisked from hotels in ambulances as television reporters related tales of massive salmonella bacteria poisoning.
This time the salmonella is thought to have been residing in uncooked eggs connected with a bread pudding, and the reports of the incident, in which 379 people were hospitalized, has caused many to become wary of what they are eating.
It`s the eggs that are causing most of the confusion. By this time most Americans are aware that 30 percent or more of the country`s poultry probably is contaminated with some salmonella bacteria and thus must be cooked thoroughly before eating, according to government estimates. But there aren`t many people out there craving raw chicken.
Not so with eggs. Raw and partly cooked eggs are essential ingredients in homemade mayonnaise, hollandaise, Caesar salad, ice cream, egg nog, mousse and meringue, not to mention those three-minute, soft-boiled eggs and the sunnyside-up ones with the runny yolks. And many people have called the Tribune Food Guide asking whether they can safely continue to enjoy those dishes.
Most hotels, restaurants and caterers have stopped using any raw eggs in their foods, but is this a situation dire enough to cause major consternation on the home front?
The answer from official sources is yes. Spokesmen for the Chicago Board of Health, the Centers for Disease Control in Atlanta and the Institute of Food Technologists say that, to be safe, all eggs must be cooked to a temperature of at least 140 degrees throughout before consumption. For spokesmen speaking to a large, diverse audience, that is the easiest way to deal with a ticklish situation.
Until a couple of years ago there was no evidence that there were any salmonella bacteria in unopened, unfractured eggs. The organisms, especially salmonella enteritidis, often were present in flocks of chickens and were found on the outside of eggshells; so egg producers took great pains to clean them and cautioned against using any eggs that had been cracked. But the inside was felt to be safe.
By the late 1980s this attitude changed after an outbreak of salmonellosis in a New England nursing home that killed several people was traced to unbroken eggs. Subsequent investigation turned up other cases, mostly concentrated in the Northeast, but in August 1988 the Illinois Department of Public Health issued a warning on whole eggs after finding some that were contaminated, says Dr. J. Todd Webber, a spokesman for the Centers for Disease Control, which monitors incidences of bacterial contamination and food poisoning.
This does not mean that every egg is infected or that even every egg from an infected chicken contains salmonella. The CDC now estimates that 1 in 10,000 eggs may have a trace or more of salmonella enteritidis, says Webber. Others think that may be an overestimate.
”I think that`s an irrational number,” says Lloyd Witter, professor of food science at the University of Illinois and a regional spokesman for the Institute of Food Technologists, based in Chicago. ”Proving there`s bacteria inside of whole eggs isn`t easy. The actual number is up for grabs. Nobody knows for sure.”
Even 1 in 10,000 isn`t a lot when you think about it, says Webber. If the normal person eats 200 eggs a year, that means he has a 1-in-50 chance that one of those 200 eggs will be contaminated.
The greatest danger comes when eggs are pooled, that is, when large numbers of eggs to be used in a recipe are mixed together, as may have happened in the Chicago outbreak. In that case, investigators believe that raw eggs used in a bread pudding or the topping were not properly cooked and were allowed to stand unrefrigerated for a period of time in which the salmonella could have multiplied.
The egg is one of the best culture mediums available for sustaining growth, says Webber. Between 40 and 140 degrees the salmonella bacteria will multiply rapidly, so that a ”pool” of eggs with one contaminated egg soon could be totally infected.
Obviously, caterers, restaurateurs and others who feed large numbers of people should take steps to prevent such occurrences by keeping eggs refrigerated and cooking them thoroughly or by using liquid eggs that have been pasteurized. But what about Grandma Millie`s mousse?
That`s a tough question, says the IFT`s Witter. ”To be safe, tell her to cook everything. That way she doesn`t take a chance. . . . I personally would eat the darn thing, but you can`t tell that to the general public. Then anybody who got sick would blame it on raw eggs.”
Salmonella isn`t a very hardy bacteria, authorities agree. It is killed easily by heat, it doesn`t reproduce in cold and it tends to die off in acidic solutions such as those containing lemon juice or vinegar. Once it gets into the human digestive system it still must contend with the body`s immune defense system as well as acids and other competing organisms in the stomach and intestines. So most people need to ingest a sizable number of bacteria before they feel ill effects.
For most healthy people a few of the salmonella bacteria may cause a mild illness or none at all. But for infants, the elderly or those with impaired immune systems the effects can be much more severe, even leading to death, says Webber.
Despite the warnings, there still are many good cooks who prefer to go ahead with their Caesar salad dressings (”I just add extra lemon juice,”
says one) and other recipes using raw eggs (”I get my eggs from a private farm,” says another), but they still are careful not to increase the risk by pooling eggs, letting them sit at room temperature for any length of time and feeding them to large numbers of guests.
”It`s one thing to take a chance on making something with a raw egg for yourself and another thing to feed it to a bunch of your friends,” says one cooking teacher.
