Molecular methodology in Food Microbiology diagnostics: trends and current challenges

Abstract

Foodborne diseases are among the most serious public health concerns worldwide. Consequently, the application of microbiological controls within the quality assessment programs in the food industry is a premise to minimize the risk of infection for the consumer. Classical microbiological methods involve, in general, the use of appropriate pre-enrichment and enrichment, isolation on selective media, and subsequent confirmation using morphological, biochemical and/or serological tests. They are laborious, time consuming and not always reliable. A number of alternative, rapid and sensitive molecular methods for the detection, identification and quantification of foodborne pathogens have been developed to overcome these drawbacks. However, until now, they have shown low practical implementation for monitoring and microbiological control. Amplification techniques have a number of advantages including improved speed, excellent detection limit, specificity, sensitivity and potential for quantification as well as easy automation. Major drawbacks are the cost of the analysis and the qualified personnel needed to carry out the experiments, plus the lack of standardisation of protocols approved by normalisation bodies. Moreover, the cost of reagents is decreasing and more qualified people are available to perform this kind of analysis. Efforts on standardisation and normalisation of these techniques are a key priority.The molecular methods, in conclusion, are a promising alternative that can substitute or complement the current reference methods in food microbiology diagnostics. More suitable and reliable results can be achieved in terms of speed and precision, and can detect and enumerate specifically viable microorganisms.

Evaluation of a novel Listeria enrichment broth combined with a real‐time PCR diagnostics assay for the specific detection of Listeria monocytogenes in RTE pork products

“…Alternatively, these positive deviations may in fact be true results, indicating that this new method is more sensitive than the Listeria Precis method for detecting L. monocytogenes in RTE pork products. Furthermore, negative deviation was not detected which demonstrates the robustness of the alternative method as food components such as organic compounds, calcium ions, glycogen and lipids have been demonstrated to inhibit PCR (Rodriguez‐Lazaro & Hernandez, ).…”

Detection of Listeria monocytogenes in Several Types of Frozen Meat in Baghdad city

“…A possible explanation for these discordant results is that DNA from dead or viable, but non cultivable, L. monocytogenes cells was detected by the alternative method in the food matrix [55,56]. Furthermore, negative deviation was not detected, which demonstrates the robustness of the alternative method, as food components such as organic compounds, calcium ions, glycogen, and lipids were demonstrated to inhibit PCR [57].…”

Development and validation of a rapid real-time PCR based method for the specific detection of Salmonella on fresh meat

“…Possible biological contaminants such as blood and fats present on animal carcasses which can cause PCR inhibition are also diluted. The bacterial cell pellet was washed in PBS prior to DNA isolation to reduce the concentration of enrichment medium which may also cause PCR inhibition (Rodriguez-Lazaro & Hernandez, 2006).…”