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Lauren Davis, Jessye Bemley, & Raquel Teasley

Summer team develops food safety and supply model to minimize consumer threat


In collaboration with the National Center for Food Protection and Defense, Georgia Tech hosted students Raquel Teasley and Jessye Bemley (left & right) and associate professor Lauren Davis (center) to study the supply channel of a common food product. As part of the U.S. Dept. of Homeland Security’s Summer Research Team Program for Minority Serving Institutions, their goal was to create a successful model for predicting the impact a contaminated product would have on its various distributors and consumers.

Next time doctoral student Jessye Bemley and graduate student Raquel Teasley entertain the idea of eating out, they might consider more than cravings and cost. These industrial engineering majors from North Carolina A & T State University know the ingredients for many menu items have followed a long chain of production and distribution with each step offering the potential of direct or cross-contamination from biological or chemical toxins.

Bemley and Teasley spent their summer at Georgia Tech alongside their university professor Dr. Lauren Davis. As part of the U.S. Department of Homeland Security (DHS) Summer Research Team Program for Minority Serving Institutions, the team advanced research in the food supply chain security, preparedness and resiliency. The program, administered for DHS by the Oak Ridge Institute for Science and Education is designed to increase and enhance the scientific leadership at Minority Serving Institutions in research areas that support the mission and goals of DHS.

The three-member team collaborated with a Georgia Tech research group that had been developing the project for a couple of years. Georgia Tech is one of many university research partners comprising the National Center for Food Protection and Defense (NCFPD). One of 12 DHS Science & Technology (S&T) Directorate Centers of Excellence, NCFPD addresses the vulnerability of attack to the nation’s food system through unintentional contamination with biological or chemical agents.

The team’s objective was to create a case study for how a contaminated food product could impact the supply-chain of that product and infect the end user: the consumer body. They wanted to know how many consumers would be affected in the event of a bioterrorist attack targeting a specific food product in the food industry.

“We need to know how many potentially contaminated products are on the shelf, the buying behavior of the consumer, and the probability that someone is going to get sick from consuming that product,” said Davis.

In the event of an attack, emergency responders could use the case study to efficiently locate where that contaminant would be and might end up, and within what time frame.

“The ultimate goal would be to help a producer of a food product understand the risk associated with their particular supply chain design.” Davis explained. “I think it’s pretty important to make sure our food isn’t turned into a weapon.”

For the case study, the team needed to create a model to determine the average number of individuals that would become sick at a given point in time. They did this by building a Markov chain model: a probability model that can represent processes that evolve over time.

To create the model, the team defined variables that describe the number of people who purchased a contaminated product, the number of prior purchasers who developed symptoms after consuming that product, and those who consumed the product but developed no symptoms.

Other factors, like the probability of someone purchasing the contaminated product in the first place, also played a role in the model. The team collected data within the three main food distribution channels: food service, food manufacturing and food retail. Their sources included industry professionals and chefs, poison control center analysts and researchers who developed dose-response models for contaminants like salmonella and e-coli.

Besides honing teamwork skills, the 10-week research program built the team’s programming and logic skills.

“The students wrote their own program to read the input data and perform the necessary calculations,” said Davis, who enjoyed the experience and considered the program successful in exposing her team to cutting edge research and integrating them into a prominent research community. “We intend to continue to collaborate with the faculty and students and provide more research opportunities in this particular field.”

Participating in applicable, real-world research is what Teasley loved most about the DHS summer research team program. As a self-prescribed food junkie, she enjoyed learning more about the food product her team modeled. Bemley felt the same way.

“Once you start to get really into it [researching the food product], you just start finding out all these different facts and it’s just like, wow!” she said.

A decade from now, Davis sees herself continuing to be involved with interesting, cutting-edge research. Like her two students, she enjoys delving into issues of public importance and making a difference. That is one reason she chose to teach at a minority serving institution and apply for the summer research team program.

“I like being able to mentor the students and potentially serve as a role model as a female engineer,” she said.

By the end of the summer, Davis felt her team had advanced in estimating the morbidity caused by a contaminant within the various distribution channels. The project is still ongoing to collect more data, simplify assumptions, and further develop the Markov chain model. Both students are continuing the research project at their home university and recommend the program to others.

“Go in with open eyes and don’t limit yourself to what you know,” suggested Teasley. “You can always learn something.”