Bad eggs indicted in Salmonella probe.

Bad eggs indicted in Salmonella probe

When Edward E. Telzak and his crew of sleuths arrived at a New York City public hospital in 1987 to investigate an outbreak of food poisoning, they knew the illnesses stemmed from Salmonella enteritidis bacteria but they didn't know where the microbes orignated. After an extensive probe, Telzak's team identified the culprit. The diarrhea afflicting 404 hospital patients, and the deaths of nine severely ill patients already suffering from lowered immunity, apparently resulted from a batch of bad eggs.

Between 1976 and 1989, the incidence of S. enteritidis infections rose more than ninefold in the northeastern United States, according to the Centers for Disease Control in Atlanta. Scientists cannot entirely explain the surge, although past investigations have impliated Grade A raw eggs as one source of the bacteria. Telzak's team probed the largest U.S. hospital outbreak of Salmonella food poisoning to date, which they describe in the Aug. 9 NEW ENGLAND JOURNAL OF MEDICINE.

The first clue to the cause of this outbreak came when Telzak's crew discovered that food poisoning symptoms appeared in 41 percent of the hospital patients eating low-salt meals but in only 28 percent of those eating the hospital's regular-salt meals. Suspecting a lunch served on July 28, the scientists soon focused on a tuna-macaroni salad made with either of two types of mayonnaise -- a commercially prepared mayonnaise or a low-salt version prepared in the hospital kitchen with raw eggs.

Laboratory tests revealed S. enteritidis in both the regular tuna salad and the low-salt version, but the researchers saw no trace of the microbe in the canned tuna or the commercial mayonnaise--a finding that implicated the hospital's own mayo and perhaps the eggs used in its preparation. Sure enoguh, the team found S. enteritidis in the reamining eggs left in the hospital's pantry. The researchers believe kitchen staff inadvertently contaminated the regular-salt tuna salad by stirring it with the same paddle used to mix up the low-salt version, says Telzak, who conducted the investigation while working for the city health department. He has since moved to Memorial Sloan-Kettering Cancer Center, also in New York City.