Charlene Wolf-Hall


Charlene Wolf-Hall remembers being eight or so and watching steam rising from silage piles on her family’s South Dakota farm (near Mitchell). She believes an interest in scientific inquiry was planted as her father explained to her the processes of fermentation. She became a farmyard scientist, experimenting with molds, fermentation, and decomposition as she collected silage, grain and discarded food samples and cultured colonies of molds in jars and bottles. Her parents, she says, were tolerant, as long as her “work” remained outdoors.

Today, Wolf-Hall is an Associate Professor of Food Microbiology in the Department of Veterinary and Microbiological Sciences. Her Ph.D., from University of Nebraska-Lincoln (1995) in Food Science and Technology with an emphasis in Food Microbiology and Food Toxicology, built upon her Bachelors and her Masters degrees in Microbiology from South Dakota State University in Brookings. Although she is now on an 85% research contract, she has taught a wide variety of courses, mainly in interdisciplinary food science and food safety areas. Wolf-Hall’s teaching has been positively recognized by students, who nominated her for Carnegie Professor (these were nominations by the teaching academy, not students) of the Year in 2005, and to deliver a “Last Lecture” in 2000.

Wolf-Hall’s childhood interest in molds and fermentation still drives her research, which is far more sophisticated now. As a food microbiologist, she now studies microorganisms in food, and specifically works with molds in grain, culturing molds and screening for toxins. The importance of this work is in beginning to understand how these molds cause disease in humans and animals, and how food scientists can interrupt that process. With her dissertation research she began her work with the mycotoxin-producing mold, Fusarium graminearium, as it affects corn and wheat. (Fusarium graminearium produces the condition commonly known as wheat scab.) Wolf-Hall’s research differs from that of plant pathologists in that she is interested in exploring post-harvest methods for dealing with mycotoxin contaminated grain. This will help ensure the safety of the grain, and salvaging contaminated grain for higher end use could greatly improve the economic outcome for regions severely affected by pre-harvest plant diseases or grain storage and processing problems.

Because the science that drives this research is interdisciplinary, Wolf-Hall regularly works with cereal scientists, engineers and economists. A recent project has allowed her to work with the malting and beer brewing industries to understand and control Fusarium in the barley used for making malt (and brewing beer). The goal of this research is to reduce toxin production, which can increase during the fermentation process, while saving the grain, without quality reduction, harm to the yeast, or the use of unsafe chemicals. Wolf-Hall’s team has developed unique ways to process barley using hot water or electron beam radiation. In addition, they have experimented with two chemicals, ozone and hydrogen peroxide, both of which are already approved for organic processing because they break down so easily.

This research has placed Wolf-Hall among a small number of scientists who work at the intersection of microbiology and cereal science, as grain microbiologists. She has become an invited consultant for the Scientific Advisory Panel for the American Association of Cereal Chemists. As part of this work she is regularly consulted by industry. For example, in 2001, after several wet harvest years, she received calls from milling companies who had had their flour rejected on the international market because of high microbe levels. Because the criteria for normal loads had been established during a period of drought, Wolf-Hall hypothesized that grain harvest in wetter conditions, and not problems with the flour, were leading to the higher loads in the flour. Her research sought to collect data from different harvest conditions to understand what the range of “normal” across harvest conditions might be, and to catalogue microbial load in raw grain, flour, and processed products like pasta and bread. The project also helps characterize the types of microbes (good, bad or ugly) in the harvested grain and processed products.

This research has led to a series of published articles and abstracts as well as conference presentations.

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