A recent study published in Microbiome, found that “skin-associated” bacteria can be identified on a number of different surfaces—including shoes, cellphones and computer keyboards—and that differences in the nature of these micro-bacterial communities can be used to distinguish who handled them.
By sampling a suspect’s personal items, law enforcement might have the ability to determine a person’s previous locations and movements by examining microbial communities that have been left behind.
"Human microbial signatures have already been used to match individuals to objects they've interacted with, such as computer keyboards,” said researcher, Simon Lax, who coauthored the study. “We found that even moving from one's own living room to a friend's living room leads to a highly detectable shift in microbial community structure on an individual's personal items.”
Participants in the study used a sterile swab to sample the soles of the shoes and the floor beneath them, as well as the front and back of their cell phones over a two-day period. Swabbing every hour, the participants recorded their exact location throughout the day, giving researchers an unprecedented look into the microbial communities beneath our feet. The study only consisted of two participants, and the need for further research is evident.
"Microbial forensics is an emerging field and many more studies are needed to better understand its potential utility,” Lax said in the article.
The field needs a lot more research to even determine if it can be viable. The study said that microbial forensic evidence could last at a crime scene that remained at room temperature for up to two weeks. How long until that evidence might be admitted in a court of law is obviously unknown, although even the most generate estimates are still probably over a decade.
“This current study is a small pilot, and so a major priority will be scaling up the number of individuals in these sorts of studies,” said Lax, “and seeing if we're still able to match people to objects with high precision."