In 2015 local health departments in Washington DC and Los Angeles, California investigated an outbreak of Salmonella Enteritidis that occurred at Fig and Olive Restaurants located in Washington DC and Los Angeles.

Washington DC location - A total of 159 patrons reported gastrointestinal illness after eating at Fig and Olive. Forty-one (40 restaurant patrons and one employee) were infected with Salmonella Enteritidis strain JEGX01.0008. The majority of illness onset dates ranged between August 31 and September 10. Case-patients included residents of DC as well as residents of 11 states who were visiting the Washington area. Results of a case-control study implicated menu items that included truffle oil as the likely source of the outbreak.

Los Angeles location - A total of 56 outbreak associated cases were identified by Los Angeles and California public health investigators. Twenty-five were laboratory confirmed with Salmonella Enteritidis. Eleven of the laboratory confirmed cases were patrons; 14 were restaurant employees. Patrons who tested positive were from separate dining groups and had eaten at the Los Angeles location of Fig and Olive on different dining dates. Illness onset dates ranged from September 6 and September 11, 2015. Cases shared an indistinguishable PFGE pattern, JEGX01.0008. Menu items that included truffle oil were significantly associated with illness.

Investigators learned that black trumpet mushrooms were dried at a central Fig and Olive commissary and shipped to various Fig and Olive locations. The restaurant then prepared a puree by blending the dried mushrooms with oil. Due to the absence of a kill step, investigators theorized that the mushrooms were the likely source of the outbreak.