An illuminating method of identifying harmful bacteria in food

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Food poisoning can make Danteś inferno seem like a walk in the park, which is why I was fascinated to read about a process that tests for harmful bacteria in food using a bacteriophage (phage) and portable light detection device connected to a smartphone.

The Silicon Photomultiplier (SiPM) device is a sensor that zooms low-light signals down to the single-photon (light-transmitting particle) level, helping users identify microscopic issues that otherwise go unnoticed. In this case, the issues are the pernicious bacteria, also called E. coli O157:H7, a particularly harsh strain of E. coli. that kills as many as 60 people a year in the US. The World Health Organization (WHO) recently estimated that all foodborne cases of E. coli caused more than 1 million illnesses worldwide.

After years of research, scientists Bruce M. Applegate, Euiwon Bae and colleagues of Purdue University, have successfully tested their pathogen detection device with artificially contaminated samples of ground beef.

Purdue technology, including a smartphone cradle, turns phones into on-the-spot detectors for foodborne illnesses.

Purdue technology, including a smartphone cradle, turns phones into on-the-spot detectors for foodborne illnesses.

The E. coli detection process

  1. First they infect the beef with E. coli O157:H7
  2. Next the meat is steeped in a proprietary ‘enrichment liquid’ for ten hours.
  3. The bacteriophage (virus) in the enrichment liquid infects the individual E coli bacteria.
  4. The scientists add another chemical which causes the phage-infected bacteria in the meat to glow.
  5. Finally the SiPM device counts the number of glowing light photons, sending the data by Bluetooth to the researchers’ smartphones and laptops.

Mission succeeded, Applegate and Bae have publicized their technology on a Purdue University-affiliated online website called Phicrobe. There, packets of genetically modified phage with portable SiPMs that can send the data to laptops and smartphones via Bluetooth technology are displayed. The scientists are working with the Purdue Research Foundation Office of Technology Commercialization to patent this portable light detection device with a view to identifying other pathogens such as salmonella. Applegate, Professor of Food Microbiology, is no stranger to patenting his inventions with 11 to his name already.

Our goal is to create technology and a process that allows for the cost-effective detection of the causes of foodborne illness using an easy, expedient and efficient process,” said Euiwon Bae, a senior research scientist of mechanical engineering in Purdue’s College of Engineering, who developed the technology along with Bruce Applegate, a professor of food science in Purdue’s College of Agriculture. “This time frame allows for better integrated detection and quicker action to stop more people from getting sick.”

On their website, Drs. Bruce Applegate and Khashayar Farrokhzad state that they hope to achieve three results:

  1. Enable food manufacturers to produce safe food, and comply with government regulations while maintaining a profitable food chain.
  2. Reduce testing time, resulting in shorter holding times for products and a faster response to any contamination, ultimately reducing costs.
  3. Enable better monitoring and more frequent testing with lower cost to enhance safety of foods.

Their process, they say, ‘saves lives, time and money’

The cost of this amazing invention is not listed but interested partners are invited to get in touch at

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About Author


Leah Zitter is an award-winning High-Tech writer/ journalist with a PhD in Research and clients that include the Association For Advancing Automation (A3).

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