The composition of carcass volatile profiles in relation to storage time and climate conditions

After death organisms are decomposed by a variety of enzymes and microorganisms. The decay is typically accompanied by the emission of a plethora of volatile organic compounds responsible for the unpleasant odour of a carcass and thus, for the attraction of necrophagous insects. The composition of carcass-related odour profiles strongly depends on the composition of macro-nutrients like fat, carbohydrates, and particularly protein, as well as on the presence of oxygen which influences the community of microorganisms colonising the corpse. The impact of abiotic factors like temperature and humidity on carcass-related volatile emission is less well understood although these parameters are known to have a strong impact on the growth of microorganisms. In the present study we investigated the volatile succession released from dead mice stored for one, ten and 30 days under warm/hot (wh, 22°C/80-90% RH) or cold/dry (cd, 12°C/40-60% RH) climate conditions. We identified 51 typical carcass volatiles by coupled gas chromatography-mass spectrometry and analysed the volatile profiles by multivariate statistical methods to find compounds characterising the different stages. Dead mice stored under wh conditions released volatiles much faster, in higher amounts, and in a greater diversity than those stored under cd conditions. The relatively low amount of sulphur chemicals released under cd conditions were most striking. The results are discussed with respect to their possible applicability in forensic science and insect ecology studies.