In early spring 1998, an excess of Salmonella Enteritidis infections was identified in the Canadian province of Newfoundland. Initial case investigations suggested commercial prepackaged lunches as a common source. Suspect foods were submitted for laboratory analysis. We conducted further epidemiological investigations to confirm the cause of this outbreak. Cases were residents of St. John's who had Salmonella Enteritidis phage type 8 isolated from a stool sample after February 15, 1998.
Exposure odds ratios for prepackaged lunches.
Salmonella Enteritidis phage type 8 was isolated from the cheddar cheese contained in Brand X prepackaged lunches while data collection for the case-control study was in progress. Illness was not associated with any other investigated exposure. The investigation of this outbreak in Newfoundland led to enhanced surveillance and investigations in other Canadian provinces and facilitated a timely national recall of contaminated products. In June 1998, the Ministry of Health in Ontario, Canada became aware of several clusters of cases of cyclosporiasis. No other province or territory was aware of any domestically acquired cases.