Chicago Health Department Uses Social Media To Identify Foodborne Illness

An estimated 55 million to 105 million persons in the United States experience acute gastroenteritis caused by foodborne illness each year, resulting in costs of $2-$4 billion annually. Many persons do not seek treatment, resulting in underreporting of the actual number of cases and cost of the illnesses.


To prevent foodborne illness, local health departments nationwide license and inspect restaurants and track and respond to foodborne illness complaints. New technology might allow health departments to engage with the public to improve foodborne illness surveillance. For example, the New York City Department of Health and Mental Hygiene examined restaurant reviews from an online review website to identify foodborne illness complaints.


On March 23, 2013, the Chicago Department of Public Health (CDPH) and its civic partners launched FoodBorne Chicago, a website aimed at improving food safety in Chicago by identifying and responding to complaints on Twitter about possible foodborne illnesses. In 10 months, project staff members responded to 270 tweets and provided links to the FoodBorne Chicago complaint form. A total of 193 complaints of possible illness were submitted and 133 restaurants were inspected. Inspection reports indicated 21 (15.8%) restaurants failed inspection and 33 (24.8%) passed with conditions indicating critical or serious violations. Eight tweets and 19 complaint forms described seeking medical treatment.


Collaboration between public health professionals and the public via social media might improve foodborne illness surveillance and response. CDPH is working to disseminate FoodBorne Chicago via freely available open source software.


FoodBorne Chicago tracked Twitter messages using a supervised learning algorithm. The algorithm parsed tweets originating for Chicago that included “food poisoning” to identify specific instances of persons with complaints of foodborne illness. Tweets identified by the algorithm were reviewed by project staff members for indications of foodborne illness (e.g., stomach cramps, diarrhea, or vomiting) from food prepared outside the home. Project staff members provided feedback on whether each tweet fit the criteria, enabling the tweet identification algorithm to learn and become more effective over time.


For tweets meeting the criteria, project staff members used Twitter to reply. For example, Tweet: “Guess who’s got food poisoning? This girl!” Reply: ‘that doesn’t sound good. Help us prevent this and report where you ate here (link to FoodBorne Chicago and a web form to report the illness).”


The information in submitted forms went directly into the Chicago 311 system that handles all requests for nonemergency city services. Descriptive statistics were used to evaluate FoodBorne Chicago over its first ten months of use and to compare the results of complaint-based health inspections of food establishments resulting from FoodBorne Chicago use with health inspections of food establishments based on complaints not submitted through FoodBorne Chicago. A total of 21 (15.8%) of the 133 restaurants reported through FoodBorne Chicago failed inspection and were closed; an additional 33 restaurants (24.8%) passed with conditions, indicating that serious or critical violations were identified and corrected during inspection or within a specified timeframe. Of the inspected restaurants with complaints not reported through FoodBorne Chicago, 25.8% failed and 14.2% passed with conditions.


Emerging evidence on the effectiveness of social media for foodborne illness surveillance suggests mining tweets and restaurant reviews might aid in identifying and taking action on localized foodborne illness complaints that would otherwise go unreported. CDPH food inspectors and supervisors were initially concerned that use of Twitter would overburden them with increased inspections. However, by understanding the process better and seeing the success in finding violations, CDPH members have become supportive of obtaining this information via Twitter. CDPH is currently working with the Boston Public Health Commission and the New York City Department of Health and Mental Hygiene to adapt Foodborne Chicago for use in those two cities. It is likely that new technology applied to widely used social media platforms may allow health departments to engage the public to improve foodborne illness surveillance.


See the CDC Report


See FoodBorne Chicago


See also Medical Law Perspectives, July 2012 Report: Foodborne Illness: When Grabbing a Bite Can Be Deadly