Current and emerging molecular diagnostic technologies applicable to bacterial food safety

Abstract

There is an increasing need for rapid test methods to certify the quality and safety of food products. Current tests applied for the microbiological assessment of food products are based on standard approved culture‐based isolation methods and can take several days to yield results. Nucleic acid diagnostic (NAD) tests for the identification of bacterial foodborne pathogens employing in vitro amplification technologies are capable of sensitive and specific detection of single or multiple pathogens in foods in a shorter timeframe than traditional methods. New developments in molecular biosensors have the potential to provide at‐line bioanalysis, whereas microarray‐based technologies may in the future be the NAD platforms of choice for multiple pathogen detection and identification. This article reviews current and emerging NAD platforms for foodborne bacterial pathogens that have the potential to impact food safety.

Rapid real-time PCR detection of Listeria monocytogenes in enriched food samples based on the ssrA gene, a novel diagnostic target

“…We have demonstrated the versatility of the target for the specific identification of L. monocytogenes and the detection of other Listeria species in a single test. This platform target is currently being exploited for the development of diagnostic assays for a range of important food and clinical pathogens (Glynn et al, 2006). tmRNA is coded for by the ssrA gene and it is present in high copy numbers in the cell ($1000 copies per cell) (Schonhuber et al, 2001).…”

Integrated microfluidic tmRNA purification and real-time NASBA device for molecular diagnostics

“…This high-copy-number target (RiboSEQ) contains conserved and variable sequence regions, making it ideal for application to microbial species identification in molecular diagnostics. [23][24][25] The isothermal, low-temperature NASBA process offers multiple advantages relative to the thermal cycling between three temperatures that is required by PCR: it simplifies the thermal design of microfluidic chip, it expands the range of materials and bonding methods that can be used, it increases the number of (thermally sensitive) reagents (e.g., enzymes) or components (e.g., certain valves) that can be included in close proximity on the same chip, and it reduces both the complexity of the instrument and power consumption. A further advantage of NASBA, relative to RT-PCR, is direct amplification of RNA templates without a separate reverse transcription step.…”

A multiplex PCR assay for detection of genus Salmonella, subspecies I , and serotype Typhimurium in milk

“…Además de los métodos microbiológicos estándar para la detección de S. enterica en alimentos, se ha diseñado una gran diversidad de ensayos basados en la PCR tanto de punto final como de tiempo real (7,8,9) , algunos de los cuales ya se encuentran disponibles como kits comerciales (7,10) . Aunque los ensayos de PCR en tiempo real para la detección de S. enterica en alimentos tienen gran sensibilidad, rapidez y especificidad (7,8) , los altos costos de implementación y el nivel de capacitación requerido limitan el acceso a dichas técnicas por las instituciones públicas encargadas de la inocuidad de alimentos y vigilancia sanitaria, manteniendo a los ensayos de PCR de punto final como una opción para la detección de S. enterica en alimentos en países en vías de desarrollo como es el caso de México.…”

“…Besides, the standard microbiological methods for detection of S. enterica in foodstuffs, a varied assortment of endpoint and real-time PCR assays have been designed for that purpose (7,8,9) , some of which are available as commercial kits (7,10) . Despite that real-time PCR analyses for detection of S. enterica in foodstuffs are highly sensitive, fast, and specific (7,8) , their elevated costs and the level of training needed for its implementation limits its access by public institutions in charge of food safety and sanitary survey, which makes endpoint PCR assays to be an option for detection of S. enterica in foodstuffs in developing countries as Mexico.…”