Emerging Biorecognition and Transduction Schemes for Rapid Detection of Pathogenic Bacteria in Food

The presence of unsafe levels of microorganisms in food constitutes a growing economic and public health problem that necessitates new technology for their rapid detection along the food continuum from production to consumption. While traditional techniques are reliable, there is a need for more sensitive, selective, rapid, and cost-effective approaches for food safety evaluation. Methods such as microbiological counts are sufficiently accurate and inexpensive, and are capable of determining presence and viability for most pathogens. However, these techniques are time consuming, involve destructive sampling, and require trained personnel and biosafety-certified facilities for analysis. Molecular techniques such as the polymerase chain reaction have greatly improved analytical capability over the last decade, achieving shorter analysis time with quantitative data and strain specificity, and in some cases the ability to discriminate cell viability. The emerging field of nanosensors/biosensors has demonstrated a variety of devices that hold promise to bridge the gap between traditional plate counting and molecular techniques. Many nanosensors/biosensors are rapid, portable, accurate devices that can be used as an additional screening tool for identifying unsafe levels of microorganisms in food products with no need for pre-enrichment. In this review, we provide a brief overview of available biorecognition-transduction techniques for detecting bacteria in food. We then discuss the advantages and disadvantages of each technique, and describe some recent biosensor or nanosensor technologies that are under development. We conclude by summarizing the opportunities and challenges in the field of pathogen monitoring in food systems and we focus the discussion on the strengths/weaknesses of the most popular biorecognition agents and transducer nanomaterials for biosensing.