Yelp and its user reviews help discerning diners find a good spot to eat, but public health officials in New York City have now used the online guide for another purpose–to identify three previously unidentified outbreaks of foodborne illness. In the project, officials from the Department of Health and Mental Hygiene (DOHMH) used a program to sort through some 294,000 reviews, posted between July 2012 and March 2013. They looked for complaints that might signal something gone awry with the food, such as the words “sick,” “vomit,” “diarrhea,” or “food poisoning.” Hungry yet?
From that large collection, they happened upon 468 reviews that seemed to describe symptoms of a legitimate foodborne bug. Officials did further research and interviewed 27 of the reviewers, identifying 16 people that got ill from the dining establishments they had Yelp’d about. This in turn led the department to investigate three restaurants, where multiple food violations were uncovered, the CDC reported today (May 22). They did not, however, determine what pathogen caused the sicknesses.
This project shows that comments on sites like Yelp could help officials find small, unreported sources of foodborne outbreaks. It ain’t just about finding a good omelette! Perhaps surprisingly, a majority of the people contacted did not know that they could report likely signs of foodborne illness by calling 311–NYC’s non-emergency reporting service–and only 3 percent of the original 468 illnesses were conveyed to 311.
The 311 service gets about 3,000 food poisoning complaints each year, and about one percent of those are identified as outbreak-related. In the case of the Yelp reviews, 16 out of the 468 illnesses were linked to outbreaks, for a total of 3.4 percent.
Online comments about restaurants have proved useful for scientists. One recent linguistic analysis of Yelp reviews offered a glimpse into people’s psyches.