Negative 4°C culture controls support a temperature effect under the conditions tested. They do not establish that a refrigerated autopsy specimen never contained ethanol produced earlier. A Candida albicans experiment illustrates why cold-storage evidence must retain its organism, medium and timeline.
The refrigerated controls were fungal broths
Velivasi and colleagues studied one laboratory strain, C. albicans ATCC 10231, in Brain Heart Infusion broth and Sabouraud Dextrose Broth. Five-milliliter portions were inoculated to approximately 10⁶ colony-forming units/mL. Broth pH was set to approximately 5.6.
The main 25°C cultures ran for 21 days under either strictly anaerobic conditions or an initial four-day aerobic phase followed by anaerobic incubation. Cultures at 37°C served as positive controls, reported over 120 hours. Cultures at 4°C served as negative controls; the publication reports their outcome without presenting the corresponding concentration curves or a separately detailed control time course.
These refrigerated controls were not paired fresh and decomposed autopsy blood from a series of people. Nor were they an experiment comparing different preservative concentrations in the same authentic specimen.
What the researchers found
The authors reported no ethanol or other measured alcohol production in the 4°C cultures in either broth. In contrast, the warmer cultures produced ethanol and higher alcohols, with the amount and pattern depending on medium and aeration.
At 25°C, the glucose-rich Sabouraud medium produced approximately ten times the ethanol generated in Brain Heart Infusion broth. The 37°C positive controls did not simply yield uniformly more final ethanol than 25°C cultures; for several conditions their maximum ethanol levels were similar. Temperature therefore cannot be treated as a universal linear multiplier of final ethanol concentration.
The analytical limits qualify a negative result
Alcohols were measured in duplicate by headspace GC–FID. Reported ethanol detection and quantification limits were 0.1 and 0.5 mg/dL, respectively. For 1-propanol they were 0.01 and 0.05 mg/dL. Calibration R² exceeded 0.999 for the measured analytes.
These limits describe the analytical method, not the probability that a different microbial community in authentic postmortem blood will remain inactive. The report’s negative controls establish the observed result for that experiment, rather than an organism-independent guarantee of preservation.
Later refrigeration cannot reconstruct the earlier history
The experiment did not test whether cooling reverses ethanol already produced during a warmer interval. A record showing refrigeration after laboratory receipt therefore does not, from this study alone, resolve conditions between death, body recovery, collection and receipt.
To assess a particular specimen, identify those intervals and the actual temperature records rather than replacing them with a general statement that the sample was refrigerated. A controlled finding about inhibited new formation is a different proposition from proof that the measured ethanol originated during life.
What remains outside the experiment
The researchers separately studied heat-denatured blood at 25°C with manipulated glucose and pH. Those blood experiments were not 4°C controls and should not be merged with the broth results. The paper also tested models in 93 selected autopsy cases, but it did not establish a controlled refrigerated-storage outcome for each case.
The study did not validate a maximum safe delay before refrigeration, an elapsed-time correction for an individual sample, or a threshold establishing impairment or cause of death. Its useful contribution is a defined negative result within a broader experiment demonstrating condition-dependent microbial activity.
For an authentic specimen with documented serial change despite reported cold storage, see the preserved-blood ethanol case report. That separate study should not be treated as if it used these controlled broth conditions.
Primary source
Velivasi G, Sakkas H, Kourkoumelis N, Boumba VA. Modeling postmortem ethanol production by C. albicans: Experimental study and multivariate evaluation. Forensic Science International. 2021;324:110809. doi:10.1016/j.forsciint.2021.110809.
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