Spotlight: Scientist

Dallas G. Hoover

Dallas G. Hoover - Dallas G. Hoover, Ph.D.

Dallas G. Hoover, Ph.D.

Professor, Department of Animal & Food Sciences

University of Delaware

Ph.D., Food Science, University of Minnesota
M.S., Biology, University of Delaware
B.S., Biology, Elizabethtown College

Dr. Dallas Hoover is in his 27th year at the University of Delaware (UD). Originally a biology major in college he eventually found his way to food science where he teamed-up with colleagues from around the world to conduct research, most recently in the field of produce safety. Dr. Hoover's project is being funded through collaboration between the Center for Produce Safety and the U.S.-Israel Binational Agricultural Research Development Fund (BARD). CPS staffer Alyson A. Barnes spoke with Dr. Hoover as he gives a glimpse into his career path and research.

Where are you originally from? Did it influence your field of study?
I am originally from York County in Central Pennsylvania.  Growing up, we always had pets around of some sort:, a pet sheep named Peggy, fish, various birds, a horned toad, snakes, turtles, the usual cats and dogs.  I never liked to kill animals, but bacteria were different, abstract--so I gravitated to microbiology and enjoyed it.  When I came to UD for my M.S. work in biology, my thesis involved food microbiology and I became more interested in food science. 

How did you learn about CPS?
My colleague at UD, Dr. Kali Kniel, introduced me to CPS. We worked together earlier on other projects. She is a leading expert on produce safety; I listened to her and became interested in the existing issues and problems affecting produce.

Is this also how you heard about the joint opportunity with BARD?
Actually, I had first been a proposal reviewer for BARD. After going through the process as a reviewer we put together a project team and a grant proposal for submission. Thankfully it was chosen for funding.

CPS awarded your project "Persistence and detection of norovirus, Salmonella, and pathogenic Escherichia coli on basil and leafy greens.” Can you tell me a bit about the project?
The team is Kali Kniel; Manan Sharma and Jitu Patel at USDA-ARS in Beltsville, MD; and our Israeli Co-PI is Sima Yaron at Technion University in Haifa.  Overall, our goal is to assess the persistence and transfer of norovirus, Salmonella, and Escherichia coli O157:H7 in lettuce, spinach and basil in order to gain information to enhance the safety of produce and reduce transmission of these pathogens in the field. 

Can you explain what the collaboration is like with your Israeli partner?
Sima Yaron’s component of the project is to use basil and spinach to examine persistence and the mechanisms of plant attachment used by Salmonella.  She will employ mutant strains of Salmonella to study factors affecting bacterial attachment to foliar surfaces.  In Israel not too long ago they had an outbreak involving exported basil contaminated with Salmonella.  Her laboratory group is looking at the genetics and physiology of Salmonella species related to plant-surface attachment similar to what occurred in that situation involving production, harvesting and transport of basil.

What do you feel your project will accomplish in regard to the industry?
We hope to deliver useful information valuable in the evaluation of risk to green leafy vegetables by these pathogens in real-world situations.  Obviously there is a desire to control production and harvest of these valuable foods to the point they are never contaminated with any pathogens; however, the environment for these crops is huge and open; consequently these foods are susceptible to acts of nature and unfortunate lapses or oversights.  We hope completion of this project will offer insight on assessing sampling data for these pathogens, as well as interpreting outcomes.  For example, what does sampling data really mean for determining food safety risk?  How should one respond to certain sampling data?

Where do you think the focus of food safety will be five years from now?
Like others in the business, I think we will see more consumer awareness of food safety and the tightening of regulations to ensure food safety.  Development of rapid diagnostic methods will also continue, but we will see much more with regard to the tracking of foods, traceability, rapid identification of origin regardless of the commodity, advances in international record-keeping of foods and food ingredients.  It seems that in a major outbreak the information one has is never quick enough or accurate enough to make the correct judgement before it is announced on the Today show. There is a lot of criticism and blame to go around when there is a national outbreak.  The reality is that it is never a black and white situation, it’s always varying shades of gray.

What would you say a day’s work consists of?
I spend a lot of time in my office, too much time.  I joke with my students that if I find my way to the lab I probably won’t be able to find my way back out. Right now our semester has just started, so teaching is the lead activity at the moment.  I am involved in three classes.  I teach freshman in an introductory food science class, getting their feet wet.  Then I teach the food microbiology course with a laboratory section for both undergraduate and graduate students.  We also have a seminar-type class on Friday afternoons that is interactive with the University of Maryland (UMD) as initiated by Martin Lo.  This year we are experimenting with outside speakers who link up with our class meeting rooms at UD and UMD using Adobe Connect; the speakers use their laptops, video cams and microphones to present their PowerPoint slides and entertain questions and discussion from students and faculty at UD and UMD with a live video feed from all three sites.  Our first speaker is Tom Shellhammer of Oregon State University talking about global beer-making after he spent a year’s sabbatical in Germany with their braumeisters.  Such activities as these get me out of my office and liven up the day considerably.

Outside of the office how do you spend your time?
I work some more. Of course I don’t, but it just seems like it sometimes. My wife (on the biology faculty at UD) and I joke how we always take our work home with us evenings and weekends.  There always seems to be something to do: there’s a grant proposal to write, a need to prep for tomorrow’s lecture, and issues as to why didn’t that grad student give me that data yesterday? It’s one of those jobs, but I love that no two days seem the same.

Lastly, you’ve done a good deal of research, what would you say is most memorable?
I used to do a lot of pressure processing work related to food microbiology, and we still have a pressure unit at UD in the lab. I started in that area when I was a young assistant professor and ran with it for over 20 years after my former department chair, Dan Farkas, pioneered a resurgence of the application.  When you look at pressure-treated products that are out there now, I do get a sense of satisfaction in helping that technology come along to commercial acceptance and use.  In the 1980s, people did not believe high hydrostatic pressure had any realistic value as a food processing method, but eventually the efforts of quite a number of people the world over created believers with the valuable data that were published.  It’s nice to feel a part of that.