A research team from Purdue University is the grand prize winner of the 2014 FDA Food Safety Challenge for its invention of a physical method for concentrating Salmonella to detectable levels using automated microfiltration. The technology uses miniscule filters to capture small numbers of foodborne pathogens in large volumes of liquid suspension in a process that could decrease sample preparation time from 24 to 48 hours to 2 to 3 hours.
The FDA Food Safety Challenge called on scientists and entrepreneurs to submit concepts that apply novel and/or advanced methodologies that can improve the detection of foodborne pathogens. The challenge was to improve the speed of FDA’s detection method for Salmonella with identification to the subtype/serovar level in minimally processed fresh produce. Winning concepts are those that accelerate or eliminate sample preparation and/or enrichment in the testing process, and/or employ novel techniques for detection of pathogens.
Michael Ladisch, PhD, leader of the Purdue University team, says one of his team’s biggest challenges was overcoming membrane fouling that limited filtration rates and membrane life. An additional challenge was automating the microfiltration system to enable reproducible results in a self-cleaning or sterilizing system that would allow multiples uses of the same membrane, thereby reducing cost per analysis.
Because the FDA’s laboratories must process a large number of samples to rapidly detect pathogens in fruits and vegetables, the Purdue University team’s next step will be focusing on adapting its technology so that it can maintain sensitivity with higher sample throughput. Their aim is to introduce the microfiltration technology so that it can accelerate detection of human pathogens in foods and to provide the technology in a form that can be easily adapted by industry, Dr. Ladisch told the FDA.
Pronucleotein Inc., in San Antonio, Texas, was the runner-up for its invention of fluorescent DNA aptamer-magnetic bead sandwich assays to detect Salmonella. The portable device uses small strands of DNA bound to magnets to capture foodborne pathogens, which are then tagged with pigments that can light up and be detected. The assay processing and analysis time is about 30 minutes.
Chief technology officer John Bruno, PhD, of Pronucleotein, says the rapid screening can help ease the burden of FDA inspectors at ports through rapid screening of suspect food. The team’s innovation may be a good solution for screening of foodborne and waterborne pathogens on fomites in food processing plants or in the field, including irrigation water monitoring, and in central testing laboratories, Dr. Bruno told the FDA.