What gets thrown away
The Frankfurt Campus canteen serves about 2,400 meals a day. Until last year, no one knew how much of that food ended up in the bin, or which dishes were the problem.
A team of data science students and canteen staff installed two cameras above the tray return belt in October 2025. Software trained to recognize the canteen's dishes estimated how much of each item was left on each tray. Faces and hands were never recorded.
The project was approved by the campus privacy office and the student council.
Results after nine months
In the first month, the system found that about 18 percent of food served was thrown away. Side salads, bread rolls and one particular lentil stew were the biggest sources of waste. The canteen responded by shrinking some portions, offering bread only on request and changing the stew recipe after a student tasting panel.
By June 2026, food waste had fallen to about 13 percent of food served, a reduction of roughly a quarter. The canteen estimates it saved about 11 tonnes of food and 26,000 euros.
The chefs knew some dishes came back half eaten. The data showed them exactly which ones and how much. After that, the changes were easy to make.
The software is being adapted for the university's dining halls at Main Campus this fall. Two students on the project will present the results at a European conference on food systems in October. More on the project is available on the Frankfurt Campus research page.
