Forensic science has a long history of use in criminal investigations, and an important concept in the investigative process is the principle of exchange, which states that “every contact leaves a trace”. While many of us are familiar with fingerprints and footprints, recent research has shown that bacterial populations on our skin leave unique traces on our clothes that act as a ‘microbial fingerprint’, and this can be used to identify individuals in forensic investigations. Dr Noemi Procopio, a Senior Research Fellow in the School of Law and Policing at the University of Central Lancashire, joined us on The Daily to discuss these findings and the future role they could play in forensics.