Deoxyribonucleic Acid Extraction and Quantification from Human Saliva Deposited on Foods with Bitemarks

The aim of this study is to evaluate the potential of deoxyribonucleic acid (DNA) recovery from bite marks in foods, in different collection types, from DNA quantification.

The sample consisted of 80 swabs, obtained from 20 cheese pieces, bitten by the same person, using the double-swab technique in the center and the periphery of the bite. A statistical analysis was carried out using Statistical Package for the Social Sciences (SPSS) statistical software version 20.0, with values of p < 0.05 being considered statistically significant.

The DNA was recovered in all cheese pieces, regardless of the collection types and the bite region. However, the comparative analysis of DNA recovery potential in the four swabs allowed us to infer that the collections in the central region of the bite (DC and WC) were the ones that presented better precision, in addition to extracting a higher DNA concentration, the dry swab being in the center of the bite which presented better results.

The results proved the effectiveness of the double-swab technique for collecting genetic materials in bite marks; however, in the food used, a single collection at the center of the bite would be enough, optimizing the resources and time needed for the analysis.

Due to the difficulties of physically comparing a site of a skin lesion and the dental arches of the suspect, the evidence of DNA in saliva has been used to indicate the perpetrator of the bite. In addition, the collection, preservation, and isolation of saliva DNA can be done at low cost and provide flexibility for clinical and laboratory workflow.