Proposição de metodologias rápidas na detecção de forma latente bacteriana utilizando espectroscopia de infravermelho próximo e nariz eletrônico

Abstract

Bacteria are the most widely distributed microorganisms in nature, being, among other aspects, involved in processes of production and deterioration of food and responsible for causing numerous diseases. Therefore it is essential to detect their activities in different samples. Traditional methodologies for bacterial detection require time, are susceptible to errors and can be costly. The technological development has provided the construction of equipment with high capacity in the prediction of sample components quickly and reliably. The objective of the present work was to obtain and standardize spore suspension of Geobacillusstearothermophilus (ATCC® 7953 ™) for further analysis of the chemical sample variations using the equipment for Near Infrared Spectroscopy and Electronic Nose associated with the Chemometric method of Principal Component Analysis or Principal Component Analysis, (PCA). The electronic nose was able to identify variations in the volatiles profile of the samples only eighteen minutes after the inoculum of the spores in growth medium, generating signals associated with hydrocarbons, acids, ethanol, organic vapors and ketone. From the spectral data of the near-infrared region, differs from the sample profiles were observed about one hour after the start of the experiment, showing vibrations in the ternary superton regions of RNH2 (1050nm), Ar-OH (930nm), H2O (940nm ) and R-OH (950nm), and secondary overtones relating to saturated carbon (1150nm). The components possibly present in the samples presented good relation with those reported in the literature and were also consistent comparing the values obtained between the techniques used. The results showed that the applied techniques present speed and reliability in the prediction of sample components, being able to contribute to the analysis of compounds and also assist in the health area related to clinical diagnoses.