Health officials link Salmonella enteritidis outbreak to truffle oil served at restaurant

A 2015 outbreak of Salmonella enteritidis that resulted in 159 illnesses was linked to truffle oil served at a single restaurant in Washington D.C., according to a recent MMWR.

On Sept. 8, 2015, the District of Columbia Department of Health was notified of a patient who became ill after consuming food at a local restaurant with multiple locations throughout the United States, according to S. Janet Kuramoto-Crawford, PhD, of CDC’s Epidemic Intelligence Service and the Center for Policy, Planning, and Evaluation at the health department in DC, and colleagues. Later that day, ED staff reported that four additional patients who dined at the same restaurant also developed gastrointestinal illnesses. Two patients were confirmed to be infected with Salmonella group D, and an outbreak investigation was subsequently launched.

The health department reported in a news release that the restaurant involved in the outbreak was Fig and Olive. From Sept. 9 to Oct. 28, 2015, health officials interviewed 254 people who recently ate at the restaurant. Among them, 159 had confirmed (n = 40) or probable infections related to the outbreak, and 95 were used as control subjects throughout the investigation.

Most infections (90%) occurred from August 31 to September 10. Those affected by the outbreak included DC residents and residents of 11 U.S. states, many of whom were visiting DC for Labor Day weekend. Their symptoms included diarrhea, abdominal cramps, chills, headache, nausea and fever.

Health officials compared food items consumed by 155 case-patients and 88 control subjects and found that six items were significantly associated with case status, three of which contained truffle oil. Overall, 89% of case-patients consumed a truffle-oil–containing item vs. 57% of controls (P < .001).

A routine restaurant inspection was performed 1 day after the first cases were identified. During the inspection, the DC Public Health Laboratory tested several food and environmental samples. Truffle fries were the only item to screen positive for Salmonella; however, the bacteria were not isolated during confirmatory testing. Meanwhile, an inspection at the restaurant’s New York-based commissary led by the FDA and New York State Department of Agriculture and Markets “yielded no significant findings,” Kuramoto-Crawford and colleagues wrote. Due to concern of the outbreak, however, the restaurant’s license was suspended from Sept. 10 to Sept. 15. Since it reopened on Sept. 16, no additional cases of Salmonella enteritidis have been reported.

Although health officials could not confirm that the PCR-detected Salmonella in truffle fries led to the illnesses or matched the outbreak strain, Kuramoto-Crawford and colleagues noted that the epidemiologic evidence strongly suggests that truffle oil was the likely source of the outbreak.

“Public health officials and consumers should be aware that truffle oil has been implicated as the likely source of a Salmonella enteritidis outbreak and could possibly harbor this pathogen,” the researchers wrote. “Timely engagement of the public, health care providers and local and federal public health officials is particularly critical for early recognition of outbreaks involving common foodborne pathogens, such as Salmonella enteritidis.” – by Stephanie Viguers

Reference:

Kuramoto-Crawford SJ, et al. MMWR Morb Mortal Wkly Rep. 2017;doi:10.15585/mmwr.mm6610a4.

Disclosure: The researchers report no relevant financial disclosures.