‘the sickly sweet smell of rotting flesh’-scented bodywash
Clarification: Scientists are not looking for the “smell of death”, but for the unique profile of molecules specific to decomposing humans when compared to other similar animals.
First of all – who cares? Forensic anthropologists care, because they want to help find dead human bodies in places populated by so many other dead critters. The wildfires in California are an example. With so many dead things there, how do we find the humans? Dogs can be trained (just like people, let Avery Gilbert give you a mouthful on that note) to recognize trace amounts of one particular chemical, or a signature profile, regardless of whether it is part of a much larger bouquet. If we could find the difference between dead human bodies and others, we could better inform our search.
Second thing – what’s the difference between “the smell of death” and the ‘human smell of death’ used in the headline above? Not much. This is certain because we already know “the smell of death”, and it’s called Cadaverine.
It’s got a lot to do with Putrescine, which is another part of “the smell of death” (as well as the smell of semen). Unfortunately, or fortunately, I cannot smell it; I’m anosmic; so I can’t be trusted. I’ll continue nonetheless. Cadaverine is described as the sickly sweet smell of rotting flesh, and you probably smell it more than you think (Exit 14 on the New Jersey Turnpike anyone?). How I wonder what dead bodies “really” smell like, because I am noseblind to one of its major constituents, but I will tell you this: On a midsummer afternoon, at a formal event like a wedding or church, where everyone is freshly-showered yet wafting personal microbiome clouds in competition with their carefully-crafted fragrance-enhancing products, Cadaverine trickles through the air.
Yes, a sheen of it covers these warm bodies, a fine layer of pulverized, rotting flesh, spread to every square inch by perhaps day-, perhaps week-old washcloths. I call it “dirty washcloth”, but I’d rather not. Sometimes, or in a strange animalistic way, it can actually smells good.
Oh, would you look at that, the Bvlgari Soir that’s been sitting on a test-strip on my desk for the past six days has been almost all dissipated, through the stages from complex aroma, to base notes, to one particular note, something musky, to this now lone Cadaverine. Even your cologne smells like dead people.
In this study, a validated method using a thermal desorber combined with a gas chromatograph coupled to mass spectrometry was used to identify the volatile organic compounds released during decomposition of 6 human and 26 animal remains in a laboratory environment during a period of 6 months. 452 compounds were identified. Among them a human specific marker was sought using principle component analysis. We found a combination of 8 compounds (ethyl propionate, propyl propionate, propyl butyrate, ethyl pentanoate, pyridine, diethyl disulfide, methyl(methylthio)ethyl disulfide and 3-methylthio-1-propanol) that led to the distinction of human and pig remains from other animal remains. Furthermore, it was possible to separate the pig remains from human remains based on 5 esters (3-methylbutyl pentanoate, 3-methylbutyl 3-methylbutyrate, 3-methylbutyl 2-methylbutyrate, butyl pentanoate and propyl hexanoate). Further research in the field with full bodies has to corroborate these results and search for one or more human specific markers. These markers would allow a more efficiently training of cadaver dogs or portable detection devices could be developed.
Rosier E, Loix S, Develter W, Van de Voorde W, Tytgat J, Cuypers E (2015) The Search for a Volatile Human Specific Marker in the Decomposition Process. PLoS ONE 10(9): e0137341. DOI: 10.1371/journal.pone.0137341
Post Post Script:
Sensory Psychologist Avery Gilbert features the “I Smell Dead People” installments on his blog First Nerve.