Studies tracking the source of foodborne outbreaks traditionally involve telephone interviews several days after illness onset, and can be adversely affected by participant recall. This project evaluated Ethica as a new technology for gathering data on food consumption and occurrence of gastrointestinal illness. This pilot study provided a unique opportunity to measure the extent of participant recall bias and the resulting limitation of current investigation strategies.
University students were recruited for a project to determine the utility of Ethica. Students are a good target population, as most have smartphones and frequently use them for data sharing and communication. Students are also often challenging to recruit using current interview methods. Further, many are learning to cook, or eat out frequently, elevating their risk for foodborne disease.
Over a 10 week period, participants were asked to report any gastrointestinal symptoms using Ethica. During the first 10 days, participants were also asked to take photos and answer 3 times daily surveys on recent food choices. Participants reported whether they were eating in restaurants or take-out food. The Ethica app linked participant data to location. Participants also completed an online survey either 1 or 2.5 weeks after day 5 asking them to recall their food choices for days 2 to 8. By comparing the survey with the Ethica data, the extent of recall bias was assessed. This proof of concept study also examined the feasibility of using Ethica to support investigation of enteric illness and inform dynamic simulation models of outbreak detection. Using participants’ reported experiences with the system, the project identified hurdles to scaling up the use of Ethica to a larger, more diverse study population and to applying this technology to other questions not sufficiently answered using traditional survey techniques.