A team at the University of Massachusetts Amherst along with food scientist, Lili He, developed the tool which could be of use to cooks for fresh fruits and vegetables, once available commercially.
An analytical chemist and expert in detection methods for food contamination, Lili said, "People around the world cook their vegetables before eating, but here in the U.S. more and more people like to eat these foods raw. This gave us the idea that a quick test that can be done at home would be a good idea."
Insisting on the importance of microbial contamination research, she added, "It has been a problem for a long time, but it is now the number one concern for food safety in the US".
Lili, along with Lynne McLandsborough, a food researcher, reported on their two-step method - one chemical, one optical - in two papers this year. They designed a reliable and sensitive bacteria-detecting chip that can test whether food or liquid samples carry a bacterial load. The chip, used with a light microscope for optical detection, relied on what Lili called a "capture molecule," 3-mercaptophenylboronic acid (3-MBPA) that attracts and binds to any bacteria.
According to the accompanying report, the chemical detection method, "surface-enhanced Raman spectroscopy" or SERS, relied on silver nano-particles. The techniques are now in the patenting process.
Over the past few months, the optical detection method was adapted for possible home use. With the smartphone microscope adapter that is widely available online for about $30, it could be used to detect contamination in food items.
It would require samples of water, juice or mashed vegetable leaf to place the chemical-based chip in for detection. Lili reported that a summer high school student had developed a simple app for smart phones that can visually detect bacteria in samples containing the chip.
Lili called it just a "beginning of the work" and is hoping to get appropriate funding to continue this practical application. The study is published in the Royal Society of Chemistry's journal, Analytical Methods and an online issue of Food Microbiology.