A Deep Learning-Based Rotten Food Recognition App for Older Adults: Development and Usability Study

Background: Older adults are at greater risk of eating rotten fruits and of getting food poisoning because cognitive functiondeclines as they age, making it difficult to distinguish rotten fruits. To address this problem, researchers have developed andevaluated various tools to detect rotten food items in various ways. Nevertheless, little is known about how to create an app todetect rotten food items to support older adults at a risk of health problems from eating rotten food items. Objective: This study aimed to (1) create a smartphone app that enables older adults to take a picture of food items with acamera and classifies the fruit as rotten or not rotten for older adults and (2) evaluate the usability of the app and the perceptionsof older adults about the app. Methods: We developed a smartphone app that supports older adults in determining whether the 3 fruits selected for this study(apple, banana, and orange) were fresh enough to eat. We used several residual deep networks to check whether the fruit photoscollected were of fresh fruit. We recruited healthy older adults aged over 65 years (n=15, 57.7%, males and n=11, 42.3%, females)as participants. We evaluated the usability of the app and the participants'perceptions about the app through surveys and interviews.We analyzed the survey responses, including an after-scenario questionnaire, as evaluation indicators of the usability of the appand collected qualitative data from the interviewees for in-depth analysis of the survey responses. Results: The participants were satisfied with using an app to determine whether a fruit is fresh by taking a picture of the fruitbut are reluctant to use the paid version of the app. The survey results revealed that the participants tended to use the app efficientlyto take pictures of fruits and determine their freshness. The qualitative data analysis on app usability and participants'perceptionsabout the app revealed that they found the app simple and easy to use, they had no difficulty taking pictures, and they found theapp interface visually satisfactory. Conclusions: This study suggests the possibility of developing an app that supports older adults in identifying rotten food itemseffectively and efficiently. Future work to make the app distinguish the freshness of various food items other than the 3 fruitsselected still remains.