Engineering of Microfuidic Systems for Rapid Detection of Food Pathogens

Microbial contamination of fresh food causes severe illness, compromises food security and has major economic and international trade consequences. Food safety and security, and disruption of intra-national and international trade in fresh foods have obvious impacts on the sustainability of global food supplies. Protocols to enable rapid detection of pathogens in foods that are both exported and imported into the U.S. are of importance for enhancing food safety, as well as informing global trade policy and stakeholders responsible for ensuring the security of the US food supply. The technology is still being developed, but at the same time we are beginning to analyze potential impacts.

The concentration of cells from food derived samples that utilizes hollow fibers in an integrated microfluidic system provides a window on future technology for rapid pathogen detection. The lessons learned have led to a number of prototypes that are currently being validated for automated detection of pathogens in food derived samples. In these systems, a large volume of extract is concentrated 500 to 1000 fold. The resulting small volume has a sufficient concentration of bacterial cells, so that they may be effectively probed for presence of pathogens on a “first alert” basis. A positive result, obtained in a time span of about an hour, would signal the need for subsequent analysis using PCR, antibody based capture and identification, analysis in a microfluidic system, and/or plating coupled with light scattering identification.

The results of rapid methods, currently under development, must be coupled with statistical techniques to define the best way to selectively sample the huge quantities of vegetable produce that are shipped into and across the US. Rapid detection is important since it could help to support both source and border interventions to detect biotoxins and other pathogens in foods and guard against their distribution, in a manner not previously possible. This paper presents the current status of microfluidic technology for rapid cell concentration and its possible impacts on both national and international intervention alternatives and their consequences, both positive and negative.