Center for Food Safety

Consumers have long been warned against the hazards of eating raw cookie dough. As more cases of foodborne illness are linked to contaminated wheat flour, University of Georgia food safety experts are touting the risk in a louder, more forceful voice, while searching for ways to eliminate foodborne pathogens on wheat products.

In wheat-related cases, the common carriers of the pathogens are cookie dough, cake batter and raw wheat flour. The most recent outbreak started in May and was linked to wheat flour contaminated with E. coli 026 bacteria. Three brands of contaminated all-purpose flour were found at grocery stores in eight states, to date. So far, 21 cases of E. coli 026 infections have been reported.

In 2005, 26 cases in the U.S. were linked to cake-batter ice cream and in 2008 a cluster of cases in New Zealand were connected to an uncooked baking mixture. In all of these cases, the pathogen was Salmonella. In 2009, an E. coli O157:H7 outbreak resulted from consumption of raw cookie dough.

“In the past, the reason we warned people not to eat cookie dough was not because of the flour, but because of the raw eggs,” said Francisco Diez, director of the UGA Center for Food Safety located on the university’s campus in Griffin, Georgia. “The two main pathogens linked to wheat products are Salmonella and E. coli.”

Diez says these cases could have been prevented if the flour had not been consumed raw.

Two University of Georgia College of Agricultural and Environmental Sciences food scientists have been presented awards of excellence from the International Association for Food Protection (IAFP). Distinguished Research Professor Emeritus Larry Beuchat and Professor Francisco Diez were recognized at the association’s annual meeting held July 21–24 in Louisville, Kentucky.

Beuchat received the Maurice Weber Laboratorian Award in recognition of his outstanding contributions in the laboratory. The award also honors his commitment to the development of innovative and practical analytical approaches in support of food safety.

He joined the Department of Food Science and Technology on the UGA Griffin campus in 1972 and has since published five books and 530 refereed scientific journal articles.

Beuchat is a world authority on the microbiology of fruits, vegetables, nuts and legumes; methods for detecting yeasts, molds and pathogenic bacteria in foods; metabolic injury of bacteria and fungi; relationships of water activity to microbial growth; antimicrobial compounds in foods; fermented foods; thermal resistance of mold ascospores; and food preservatives.

Most of Beuchat’s research at the UGA Center for Food Safety in Griffin focuses on how food safety issues relate to foods of plant origin.

Food safety research usually involves analyzing live populations of foodborne pathogens like Salmonella, Listeria and E. coli, but University of Georgia food scientist Henk den Bakker fights pathogens by developing computer software. 

University of Georgia food microbiologist Xiangyu Deng’s work in the emerging field of bioinformatics led to his selection as a Creative Research Medal winner for 2017. 

The medal is one of the prestigious honors bestowed annually by the UGA Research Foundation. Awards are given to outstanding faculty, postdoctoral fellows and graduate students in recognition of excellence in research, scholarly creativity and technology commercialization at UGA.

Deng, an assistant professor of food microbiology with the Center for Food Safety (CFS) on the UGA Griffin campus, was recognized for creating a cloud-based software tool that quickly classifies strains of salmonella, one of the most prevalent foodborne pathogens in the United States and worldwide. The Centers for Disease Control and Prevention (CDC) estimates that 1 million foodborne illnesses and 380 deaths in the U.S. each year can be linked to nontyphoidal salmonella.

The SeqSero system identifies serotypes, or distinct strains of salmonella, from infected humans, animals, foods and the environment using whole genome sequencing. This system allows for accurate, fast “fingerprinting” of any salmonella strain and replaces a complicated, time-consuming laboratory protocol. Analysis time using SeqSero takes just minutes — analysis using the old system took days — while adding no extra cost.

Last summer, seven seniors from Pike County High School (PCHS) in Zebulon, Georgia, with an aptitude for science made a commitment to work alongside University of Georgia Griffin campus scientists three days a week for the entire school year. This month, they will complete their yearlong partnership.

The students, Courtney Bagwell, Dylan Blohm, Abigail Chasteen, Nikki Dodson, Megan Pitts, Taylor Thomas and Talisa Watts, are the first group to take part in the off-campus internship. 

"The beauty and the flexibility of the (Pike County STEM) Academy is that we have a lot of standards, but we can pick and choose the ones that fit with science and math, and then add in the technology and the engineering through agriculture," said Greg Waits, the program's coordinator and the agriculture education teacher at the high school. 

Students are selected for the program based on their test scores in math and science. Then they take advanced classes in science, technology, engineering and math (STEM) areas during their freshman, sophomore and junior years before participating in the off-campus experience at UGA-Griffin. 

Formally, the students earn Advanced Placement science credits for participating. They also gain a wealth of information and personal experience. 

Mike Doyle doesn’t eat raw bean sprouts, medium-rare hamburgers or bagged salads. He isn’t on a special diet, but as director of the University of Georgia Center for Food Safety in Griffin, Georgia, he studies the food pathogens that sicken thousands of Americans each year.

Doyle works closely with the food industry, consumer groups and government agencies, like the Centers for Disease Control and Prevention (CDC) in Atlanta, on issues related to the microbiological safety of food. He also serves as a scientific adviser to groups like the World Health Organization, the U.S. Food and Drug Administration (FDA) and the National Academy of Sciences.

For a time, foodborne illness was most often connected with undercooked meats, and most product recalls and outbreaks were connected to meat products. Today, 33 percent of cases are tracked back to raw produce, Doyle said. In an odd Catch-22, he says America’s efforts to become healthier, including eating more produce, and efforts by the CDC and local health departments to do “a better job tracking sources” have led to the increase of reported foodborne illness cases linked to produce.

For years, food scientist Francisco Diez studied and admired the work of University of Georgia Regents’ Professor Mike Doyle, but the two researchers’ paths never crossed. For the next year, they will work closely together as Diez transitions into Doyle’s role as director of the UGA Center for Food Safety in Griffin, Georgia. Doyle, a leading authority on foodborne pathogens, came to the UGA College of Agricultural and Environmental Sciences in 1991 to establish the center. As director, he developed a research program that promotes collaboration among the food industry, the university, and federal and state agencies.

A native of Mexico, Diez earned a bachelor’s degree in food technology from the Monterrey Institute of Technology and Higher Education, and completed master’s and doctoral degrees in food science at Cornell University in New York. He comes to UGA from the University of Minnesota, where he was a faculty member and head of the Department of Food Science and Nutrition. His research focuses on the family of pathogens known as enterohemorrhagic E. coli, an important cause of food contamination and foodborne illness.

Researchers at the University of Georgia found that pathogens, like salmonella, can survive for at least six months in cookies and crackers. The recent study was prompted by an increased number of outbreaks of foodborne diseases linked to low-water-activity, or dry, foods. Larry Beuchat (pictured left), a Distinguished Professor Emeritus and researcher in the UGA College of Agricultural and Environmental Sciences, led a study to see just how long bacteria that cause foodborne illness can survive in certain foods.

“There have been an increased number of outbreaks of diseases associated with consumption of contaminated dry foods. We wouldn’t expect salmonella to grow in foods that have a very dry environment,” said Beuchat, who works with the Center for Food Safety on the UGA campus in Griffin.

Beuchat and study co-author David Mann, a research professional in the center, found that not only can harmful bacteria survive in dry foods, like cookie and cracker sandwiches, but they can also live for long periods of time.

For the recent study, published in the Journal of Food Protection, researchers used five different serotypes of salmonella that had been isolated from foods involved in previous foodborne outbreaks. “Isolates were from foods with very low moisture content,” Beuchat said.

In a recent study funded by the U.S. Food and Drug Administration, University of Georgia researchers found that produce containing bacteria are likely to contaminate other produce items through the continued use of knives or graters — the bacteria latches onto the utensils commonly found in consumers’ homes and spreads to the next item. Unfortunately, many consumers are unaware that utensils and other surfaces at home can contribute to the spread of bacteria, said the study’s lead author Marilyn Erickson, an associate professor in the College of Agricultural and Environmental Sciences’ department of food science and technology.

“Just knowing that utensils may lead to cross-contamination is important,” Erickson said. “With that knowledge, consumers are then more likely to make sure they wash them in between uses.”

Erickson has been researching produce for the past 10 years. Her past work has mainly focused on the fate of bacteria on produce when it’s introduced to plants in the field during farming.

In 2013, she was co-author on a study looking at the transfer of norovirus and hepatitis A between produce and common kitchen utensils — finding that cutting and grating increased the number of contaminated produce items when that utensil had first been used to process a contaminated item.

Georgia Tech President Bud Peterson and Georgia Commissioner of Agriculture Gary Black came to Griffin on June 19 for a tour of the campus. The tour included updates on existing projects between Georgia Tech researchers and UGA Center for Food Safety scientists and research on parasites, pathogens on cantaloupes and an antimicrobial food rinse developed by CFS Director Michael Doyle and research scientist Tong Zhao. The guests also sampled Georgia blueberries in the sensory lab and heard updates on blueberry and poultry projects conducted in the Food Innovation and Commercialization Center. University System of Georgia Regent and local orthopedic surgeon Dr. Tommy Hopkins organized and attended the tour. State Representative David Knight was also on hand participating in campus tour.