Lab Members

Tonya C. Schoenfuss, Ph.D.


Dr. Schoenfuss owes her love of milk and cheese to raising nubian goats and dairy replacement heifers in 4-H in San Jacinto, California. She studied Dairy Science at Cal Poly, San Luis Obispo and decided to study in a country famous for dairy product research for her Junior year at Massey University, Palmerston North, New Zealand. She then started her tour of the nation heading east for her Master’s in Food Science at Virginia Tech, Blacksburg, VA, then south to Louisiana State University for her Ph.D. in Dairy Science. After surviving Hurricane Andrew and the famous heat and humidity of Baton Rouge for 5 years, she decided that taking a job north in Minneapolis at General Mills would be a nice change.  After 11 years at General Mills working as a product developer in various divisions, she decided to get back to work on cheese in 2008 at the U of MN. In addition to her research, Dr. Schoenfuss is the faculty advisor for the Joseph J. Warthesen Food Processing Center, she coaches the collegiate dairy product evaluation contest team, and teaches FSCN 1102 Food Safety, Risk and Technology, FSCN 4131 Food Quality, FSCN 4210 Taste of Germany and Switzerland Study Abroad, FSCN 5441 Food Product Development and FSCN 5541 Dairy Product Chemistry and Technology. Dr. Schoenfuss is also the Associate Director of the Midwest Dairy Food Research Center, and the Director of Undergraduate Studies for the Food Science Major.

Current Graduate Students:

Ghazal Monsefi Parapari


Ghazal is originally from Kerman, Iran. After completing her B.S degree in Food Science she moved to the United States and started working in food industry. Ghazal joined Schoenfuss Lab in the fall of 2018. Her research focuses on “Polylactose” as a dietary fiber and its purification methods including carbon filtration.  Ghazal Loves baking cakes and DIY projects.


Lisa Chou

Lisa Chou

Lisa joined the Schoenfuss lab in July 2018 and is pursuing an MS in Food Science with a minor in Environmental Health. She is originally from Oconto Falls, WI and graduated from University of Wisconsin-Madison with a BS in Food Science. After graduating, Lisa worked in quality assurance at OSI Group in Geneva, IL, and in product development at PepsiCo in Barrington, IL, where she tested sugar reduction tools in Tropicana juice and Quaker oatmeal products. Lisa’s current project involves developing a rapid method to predict process cheese functionality before cooling, which will hopefully be a useful tool for process cheese manufacturers to improve their process control. She is also involved in various student competitions and as an officer in the Food Science and Nutrition Club. In her free time, she enjoys cooking, running, painting, reading, and tasting new alternative food products like insects, impossible burgers, and Beyond meat.

Madeline Brandt 


Maddie joined the Schoenfuss lab after completing her Bachelor's degree at St. Olaf College. Her Master's research focuses on production of astaxanthin from dairy waste streams.  She is from Mahtomedi, MN, and enjoys cooking, hiking, and the outdoors.




Dustin Grossbier, M.S.


Dustin is originally from Wisconsin Rapids, WI. After completing a B.S degree in Chemistry from Northland College, he worked 10 years in food and pharmaceutical industries. After going back for a M.S. degree in Biology-emphasis in Dairy Science from South Dakota State University, he joined the Schoenfuss lab group in 2016.  His research focuses on strategies to produce reduced sodium mozzarella cheese, with focus on value added uses of dairy side streams.



Alumni Post-docs

Catrin Tyl, Ph.D.

Catrin was a postdoctoral research associate who graduated from the U of MN working on wheat phytochemicals under the guidance of Dr. Mirko Bunzel in 2012. She put her cereal chemistry background to work continuing the evaluation of soluble fiber from lactose by twin-screw extrusion. She joined the lab in 2013, and worked with Maddie quantifying astaxanthin production in a microalgae fed on dairy waste.  Catrin was an instructor for two undergraduate courses, FSCN 4112 (Food chemistry and functional foods) and FSCN 4311 (Chemical reactions in foods). Tonya and Catrin took two student groups on a study-abroad course (Taste of Germany and Switzerland). Catrin is now a faculty member at the University of Georgia, Department of Food Science and Technology.


Alumni Graduate Students

Leilany Vazquez Portalatin


Leilany joined the Schoenfuss lab in the summer of 2017.  She grew up in Hatillo, Puerto Rico (the milking city).  Leilany graduated from the University of Puerto Rico at Mayagüez with a BS in Animal Science and a minor in Food Science.  Her current project is developing a calibration curve to quantify the cellulose present in shredded mozzarella cheese using FT-NIR. In her free time she enjoys knitting, crocheting and baking, traveling and spending time with her dog.  She graduated in 2019.


Alexandra Kuechel 


Alex is originally from Morton Grove, IL.  After graduating from the University of Wisconsin – Madison with a B.S. in Food Science and a Certificate in German in May of 2014 she worked in R&D at the Kraft Heinz Company in the Meals and Desserts and Exports business units.  In August of 2015, Alex joined the Schoenfuss lab to pursue her Master’s Degree.  Her project is focused on furthering our understanding of polylactose, including developing a benchtop method for polylactose production and a carbon filtration method for purification.  Outside of lab, Alex is a member of the Dairy Products Evaluation Team and College Bowl.  In her free time she can be found baking desserts, cheering on the Badgers, Cubs and Blackhawks, reading, and checking out new restaurants in the Twin Cities area.

Jaya Dhungana 


Jaya joined the Schoenfuss lab in the Fall of 2016.  She is originally from Kathmandu, Nepal and she received her B.Tech (Food) from Tribhuvan University, Nepal.  Her research primarily focuses on studying the effect of different dough conditioners on the functionality of IWG, a perennial crop with environmental and nutritional benefits.  In her free time Jaya enjoys playing basketball and traveling.

Andrew Zumbusch

Molly Erickson


Molly joined the lab in 2013 to work on her Master’s after completing her degree in Biology from Wartburg College, Waverly, Iowa.  She worked on the difficult task of taking over 80% of the fat out of Cheddar cheese, and not having the texture of a rubber eraser.  Molly graduated with her M.S. in 2015 and is currently working in R&D at Land O’Lakes, Inc. in Arden Hills, MN.


Liz Reid


Liz was the 2nd chemical engineer in the lab and she completed her Chemical Engineering degree at Iowa State University. She worked on the polymerization of lactose by extrusion to create soluble fiber from waste products.  Liz graduated with her M.S. in 2015 and she currently works at Land O’Lakes Inc. in Arden Hills, MN as a process engineer.


Ann Pataky


Ann is the first chemical engineer in the lab and hails from the University of Illinois, Champagne-Urbana.  Ann studied the effects of sodium reduction in blue cheese, with and without the addition of KCl. She had the enviable pleasure to work with fatty acid standards commonly described as “goaty”, “cheesy” and “vomit” as she ran her standard curves for gas chromatography. Amazingly, she still likes blue cheese. Ann was on the first full Dairy Product Evaluation contest team and placed 2nd in the National contest in 2012.  She is hoping to never smell malty milk again.  She graduated with her M.S. in 2013 and is currently working in R&D at the Kraft Heinz Company in Glenview, IL.

Heather Anderson 

Heather worked on a project for her M.S. in Biology degree with a focus on food at the U of MN. She worked on expanding the calibration for intact casein measurement by FTNIR, and evaluating the effect of sample extraction method on the results for intact casein total nitrogen.

Andrea Tremaine


Andrea is a U of MN graduate 2x over and got a jump on her Master’s while working in the lab on an undergraduate research project. Andrea’s research involved two different projects to use twin-screw extrusion to better understand how to use it to make value-added dairy ingredients. The first project evaluated the effect of acid addition, moisture and starch on the ability to make puffed products with nonfat dry milk. The 2nd project used lactose as a raw material to polymerize into soluble fiber. Andrea observed first hand (and hopefully never will again) what happens when protein and starch is fed into an extruder without water, and how hard it can be to extract a screw after that. Andrea is a native of Viking country, but that didn’t stop her from being a proud cheesehead and vandalizing innocent cut-out Viking cows with Jeff. She graduated with her M.S. in 2012 and currently works in R&D at General Mills in Golden Valley, MN.

Anthony Reuter


Tony is the first of a string of Iowa residents to the lab. Dr. Schoenfuss was so pleased with what a dedicated, professional student Tony was, she has recruited 3 other Iowa students and one who went to Iowa State (something happens to the water when it goes south of MN?).  Tony had the pleasure of analyzing raw milk by tedious standard methods to investigate the effects of sample preparation and scanning method by  FT-NIR on calibration quality. He graduated with his MS in 2012 and currently works in R&D at General Mills in Golden Valley, MN.

Ellen Hystead


Ellen obtained her Bachelor’s degree at Michigan State before coming home to Minnesota to work on her Master’s.  She was co-advised by Dr. Francisco Diez and Dr. Schoenfuss and worked on the effect of sodium reduction on the safety of Cheddar cheese (adding both Listeria monocytogenes and Clostridium botulinum).  Ellen graduated with her M.S. in 2012. 


Jeff Grummer


Jeff came to Viking country after tiring of the Packer’s continuous winning seasons (although we were unable to convert him). Jeff studied the effects of reducing sodium by over 55% in Cheddar cheese using KCl and flavor enhancers. His work resulted in 3 publications during his Master’s degree.  Jeff graduated with his M.S. in 2011 and currently works in R&D at Schriber Foods in Green Bay, WI.


Ram Kumar


Ram was the first Master’s student in the Schoenfuss lab and worked on low fat Cheddar cheese. He studied improving the texture of cheese by adding hydrocolloids to replace the functions of fat.  He graduated with his M.S. in 2012 and currently works in Product Development at Agropur Inc. in Appleton, WI.


Past Visiting Students

Vanessa Reitermann


Vanessa completed her Master’s research in the Schoenfuss lab during the 2016-2017 school year.  She is from Karlsruhe, Germany and studied food chemistry at the Karlsruhe Institute of Technology (KIT). Vanessa’s project for her diploma thesis was "Rapid Quantification of Melamine in Raw Milk Using Near- and Mid Infrared Spectroscopy".  She graduated with her Master’s Degree from KIT in the spring of 2017.



Melinda Sattler

Magali D'accord


Magali was an intern in the Schoenfuss lab in the Fall of 2012.  She worked in the lab during her time as a Master’s student at INRA in Rennes, France.  Magali’s project involved working on various methods of sweet whey powder analysis.




Pierre Martin Sallard

Pierre Martin

Pierre Martin was an intern in the Schoenfuss lab in the Fall of 2012.  He worked in the lab during his time as a Master’s student at INRA in Rennes, France.  Pierre Martin’s project was looking at the interaction of carrageenan with whey protein to form aggregates.  During his time in Minnesota, he got to try cheese curds for the first time. 



Former Undergraduate Researchers

Carmen Owen-Block

 Yingxin Zhong     
Lauren Tebben                             



 Zach Metz




 Courtney Lasky




 Megan Parker   





 Kelsey Sneedon





 Ern Saputra      





 Kristine Johnson 




 Adam Roorda






 Erin Daninger