Rapid methods for foodborne pathogens detection and quantification: a review

Abstract

Foodborne pathogens cause millions of illnesses each year, therefore their early detection and quantification is an issue of major importance. The purpose of this thesis was the review of almost all rapid methods that could be implemented in food microbiology. The methods were categorized as: i.) Nucleic acid-based techniques, ii.) Spectroscopic techniques, iii.) Spectral imaging techniques, iv.) Biosensors, v.) Metabolomics and vi.) Other instrumental techniques. For each technique, the theoretical background was described along with recent applications in microbiology. Nucleic-acid based techniques were considered as one of the most sensitive and specific methods that could be invaluable in food microbiology with the well-established Polymerase Chain Reaction (PCR) variants and with the more recent approach of Next Generation Sequencing (NGS). Spectroscopic and spectral imaging techniques, even not widely implemented for microbiological purposes, seemed to have great potential with the evolvement of data analysis tools due to their non-destructive approach. Biosensors appeared to address portability, easy-of-use and low cost although their in-field applications were limited. Metabolomics along with chromatographic and –omics techniques share the same holistic approach that is closely related to phenotype, although the complexity of instrumentation, analysis procedure and data analysis maybe was the main cause of limited applications. Flow cytometry “addressed” some limitations of the past that were reducing its sensitivity and specificity although the high cost still remained a significant obstacle of wide-scale implementation. Impedance microbiology seemed to have better results when integrated in biosensors although such applications were still limited. Immunological-based techniques have begun to be more prevalent in food microbiology laboratories although the high cost of some approaches remained a limiting factor. In conclusion, the most important problem of almost all of the rapid methods included in this review had to do with the need of preliminary steps of sample processing that increased the theoretical total time of analysis, yet not in levels of conventional methods.