Is That Safe to Eat? LU Researchers Pioneer Innovative Food Safety Monitoring Device

Imagine the chef at your favorite restaurant preparing a salad for guests. Inspecting the produce to be used, he sniffs at an avocado. Is it safe to use? Knowing the answer quickly could help prevent and control foodborne disease outbreaks.

That’s the goal of researchers at Lincoln University (LU) of Missouri’s College of Agriculture, Environmental and Human Sciences (CAEHS) who are working on a new way to determine food safety quickly. They are making headway in analytical chemistry by developing a portable sensor system for on-site food safety monitoring — the first of its kind. Through this new technology and process, food safety risks will be detected in hours instead of days or weeks. At present, no such sensors are commercially available, and Lincoln University is at the forefront of related research.

“Although portable sensors have been reported elsewhere, most of them are still relying on conductivity change or antibody-antigen reactions to detect simple and fixed pathogen(s),” said Assistant Professor Dr. Qingbo (Roger) Yang of LU Cooperative Research, the principal investigator on the project. “We are advancing the detection method by pairing technology with powerful machine learning tools.”

According to Yang, there is a critical need for rapid detection methods to monitor food safety issues. Traditional methods used to test food samples can be a long process, lasting from a few days to a couple of weeks. The elapsed time for testing results is often too late to prevent contaminated food from being consumed by the public.

“The presence of foodborne pathogens increased during the COVID-19 pandemic, with lack of labor and protection measures in a time of a food shortage,” Yang said. “This has caused acts of neglect in the food process, leading to a rise in foodborne diseases over the past few years."

Yang and his team at LU are developing a portable, hand-held sensor with a specially designed Raman spectroscopic sensing head, embedded with an olfactory sensing probe. The device includes a small chamber for food sample preparation underneath the sensor. With a certain amount of heat and stirring, food placed in the chamber will quickly emit volatile organic compounds (VOCs), which act as molecular fingerprints for specific bacteria. For example, pathogenic E. coli discharges one particular chemical, indole (C₈H₇N), which signals if the food is toxic or not.

“LU’s innovative sensor can ‘smell’ and pick up the specific molecules that exist in the targeted food — even in very small amounts — with the assistance of a well-trained machine learning algorithm,” said Yang. “The portable sensor is currently being ‘trained’ to quickly assess several important contamination indicators of food to confirm whether it is questionable or not.”

At present, the first-generation sensor has been fabricated and tested with collaborative lab. An upgraded version will be built on LU campus this summer.

From the initial screening with the portable sensor at any on-site location, suspicious samples can also be further examined in the laboratory for high throughput screening, which can be completed using two major analytical instruments that are unique to Lincoln University: the Ultra-High Performance Liquid Chromatography tandem Mass Spectrometry (UHPLC-MS/MS) and Gas Chromatography tandem Mass Spectrometry (GC-MS/MS). These instruments first analyze liquid or gas samples through chromatography, the process of separating components in a mixture. Then the mass spectrometer analyzes the separated components and provides quantitative information of the chemical composition of each compound. The mixture of a sample can then be separated and detected. Results are not only qualitative but also quantitative, showing even trace amounts of chemicals.

Prospective goals for this project include rapid and sustainable strategies for preventing and controlling foodborne disease outbreaks in Missouri and other states. The same technology can also play a huge role in the fields of incense industry, military investigation, trace chemical detection, gas leakage and microbial research, etc.

This project is financially supported through the USDA NIFA-funded Evans-Allen Research Program, from February 2021 to January 2024. Dr. Yang of LU Cooperative Research is a forerunner on many of these CAEHS initiatives. For more information, contact Dr. Yang at 573-681-5036 or YangQ@LincolnU.edu.