Yelp, the bane of many a restaurateur’s existence, may have a serious upside. Words like “sick,” “vomit” and “food poisoning” used on the crowdsourced review site helped health officials track down food-borne illnesses, the Takeout reports.

Food poisoning is a significant public health issue. According to Health Canada, one in eight Canadians is affected by food-borne illness each year. That’s a total of roughly four million people stricken with bacteria, parasites and viruses thanks to consuming contaminated food. Of these cases, approximately 238 result in death while 11,600 result in hospitalizations annually.

A new study published in the Journal of the American Medical Informatics Association looked at how the New York City Department of Health and Mental Hygiene (DOHMH) uses restaurant reviews to identify outbreaks. “Identifying foodborne illness outbreaks can be challenging because not all individuals with foodborne illness are tested, and therefore they’re not reported to health departments,” Thomas Effland, a Ph.D. student at Columbia University and lead author of the study, told Consumer Reports. “Additionally, individuals may not report suspected outbreaks to public health agencies.”

In collaboration with DOHMH, researchers at Columbia University created a program “that applies data mining and uses text classification” to scan Yelp reviews for mentions of food-borne illness connected with NYC restaurants.

The program looked for instances of food-borne illness and examined related entries to determine if multiple people fell ill after posting review of the same restaurant. DOHMH epidemiologists reviewed the flagged entries manually and attempted to interview some of the reviewers about the illness.

In a pilot study, the researchers found that only 3 per cent of the illnesses mentioned on Yelp were reported through NYC’s official complaint channels. The system “has been instrumental” in pinpointing 10 outbreaks and 8,523 illnesses since July 2012, the study states.

This highlights the importance of such programs, the researchers conclude, and they reportedly hope to expand their system to other cities. Given the prevalence of online restaurant review sites, and the “decreasing likelihood” that people will report food poisoning to the government, it’s increasingly crucial to be able to pull information from social media.