November 16, 2010

The Scientist: Reid Ivy

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In 1938, a quarter of all food and water contaminations were associated with milk or milk products, according to Prof. Reid Ivy, food science. Today, less than one percent of all food-borne outbreaks are linked to dairy products. This is largely due to increased understanding of pathogens — bacteria and viruses — and improved preventative processes, such as pasteurization, refrigeration and hermetic packaging.

Ivy received his undergraduate degree in microbiology from the University of Arkansas (UA) in 2003. After his junior year, Ivy took an internship working with Tyson Foods Inc. where he was stationed in one of Tyson’s product quality control labs. His job included screening all of Tyson’s poultry products for pathogenic contamination.

This experience inspired Ivy to work for a food safety lab his senior year. After graduation, Ivy continued to work in the lab as a graduate student. In his research, Ivy characterized the survival mechanisms of Listeria monocytogenes, a lethal bacterium found in raw milk, when under stress.

Ivy then met Prof. Martin Weidmann, food science, of the University’s Laboratory for Microbiology and Pathogenesis of Food Borne Diseases and came to the University to work on characterizing L. monocytogenes using gene-sequencing techniques.

This bacterium is a safety concern because it can survive in highly acidic and highly saline environments, like the inside of the human stomach, that would normally kill other microbes. This means that normal digestion would not kill L. monocytogenes.

Ivy examined the bacterium’s behavior at highly acidic environments and various temperatures. He sought a certain temperature range that may make the bacterium vulnerable to acid treatment.

Ivy’s research also analyzed how L. monocytogenes can persist in environments where other bacteria would starve. Future research on the stress mechanisms that allow Listeria bacteria to enter a sort of microbial hibernation could lead to discovery of methods to alter these dormancy mechanisms and improve food safety.

Presently, Ivy is a post-doctorate student under Prof. Kathryn Boor, food science, and also co-teaches a course about milk safety and proper milk processing.

His research now focuses on characterizing spoilage causers, or bacteria that decrease the shelf life of dairy products. Spoilage bacteria are the most difficult microorganisms to remove from milk using conventional pasteurization techniques, so Ivy’s work intends to identify the stages in the milk harvesting process in which spoilage bacteria are introduced and to then find ways to minimize exposure to these bacteria.

Ivy’s research contributes to the University’s Milk Quality Improvement Program (MQIP), and Ivy enjoys that MQIP connects him to the dairy industry and local New York producers.

Aside from his work in academia and extension, Ivy is a former secretary of the Cornell Cheese Club (CCC), started by graduate students in food science to explore and appreciate the production stages and science of cheeses.

“I’ve been at this new job for only five months now, but my plans for the position are to gain experience in dairy processing and in relating to dairy processers in the state – whether it be large processers or small processers. Really it’s just to learn what some of their challenges are and figure out my role in helping those processers meet those challenges,” Ivy said.

Original Author: Zachary Mason