Ethical statement
We confirm that the procedures comply with national and EU legislation. Research was performed in accordance with the Declaration of Helsinki. The study was approved by the Animal Welfare Committee (OPBA) of the University of Milan (OPBA_06_2021). Before participating in the olfactory detection test, each dog owner gave informed written consent for using their dogs’ test results in research. Reporting of results follows the recommendations of the ARRIVE guidelines. Informed consent was given by each subject for publication of identifying images in an online-access publication.