Abstract

context: Evidence plays a crucial role in the forensic investigation in solving criminal cases. This evidence should be properly collected and preserved to avoid degradation and loss of evidential value. Hence, this paper describes the experimental study of collected and degraded biological fluids which can be recovered from the crime scene. aims: The study aims to assess the microbial growth on different biological fluids recovered from the crime scenes in percolation with varied temperature durations. settings and design: An experimental setup was designed to study the different biological fluids and their variation of impact on different conditions like type of sample, temperature differences and time of exposure. method and materials: Biological fluids such as saliva, urine, semen and vomit were collected and used for the study. The identification procedure of microorganisms and extent of degradation was studied by means of physical analysis, bacterial culture, fungal culture, staining for bacteria and fungus, and biochemical testing. Followed by assessment of collected samples inoculated with cotton cloth piece with specified time interval and temperatures. results: Candida albicans and Escherichia coli show maximum profuse growth in inoculated urine samples exposed to temperature 37°C with the time interval of 7 to 27 hours and 20-25°C with time interval of 48 hours. Likewise, Pseudomonas aeruginosa shows maximum growth in inoculated saliva samples exposed to temperature ranging from 20-37°C with time interval of 40 hours. Furthermore, the micrococcus mucillogens, proteus vulgaris and streptococcus pneumoniae show maximum growth in inoculated vomit samples exposed to temperature ranging from 20-37°C with time interval of 7-27 hours. Lastly, Micrococcus mucillogens shows maximum growth in inoculated semen sample exposed to temperature ranging 20-37°C with time interval of 48 hrs. conclusion: Forensic biological samples are more susceptible to the contamination by the growth of microorganism because of the nutritive substances present in each fluid. Since compositions of each biological fluid are different, therefore types of microbes growing and their effect on samples will also be different leading to destruction of forensic biological fluid samples. This study reveals the determination of microbes such as a Candida albicans, Escherichia Coli, Pseudomonas aeruginosa, micrococcus mucillogens, proteus vulgaris and streptococcus pneumoniae in urine, saliva, vomit and semen samples. Under ambient-conditions of high temperature and with specific time durations, the growth of microbes was found to be rapid. It is also to be concluded that temperature plays a major role in the preserving the integrity of samples, at high temperatures for more time, the samples will get dry and minimal amount of microorganism will grow. key messages: Detection and determination of varied microbial growth on different biological fluids of forensic importance provide prudent information to forensic experts for combating the loss of evidential value for trials and for maintaining proper chain of custody. Hence, the study aids forensic experts to collect and preserve biological fluids with in specific time duration and temperature conditions.

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