October 24, 2023 - Graduate Student Presentations

Speakers:

Cydney Jackson

Ph.D. Candidate, Tako Lab

Empire Apple (Malus domestica) Juice, Pomace, and Pulp Modulate Intestinal Functionality, Morphology, and Bacterial Populations In Vivo (Gallus gallus)

Abstract: With an estimated 5 million tons produced yearly in the U.S. within the last decade, apple consumption is considered ubiquitous. Apples are comprised of bioactive constituents such as phytochemicals and prebiotics that may potentiate intestinal health and the gut microbiome. This study aimed to evaluate the effects of Empire apple juice, pomace, and pulp soluble extracts on intestinal functionality, morphology, and the microbiome in vivo (Gallus gallus). There were five treatment groups: noninjected (NI); 18 MΩ H2O (H2O); 6% apple juice (AJ); 6% apple pomace (APo); 6% apple pulp (APu). The eggs were treated by intra-amniotic administration of the samples on day 17 of incubation. After hatching, the blood, tissue, and cecum samples were collected for further analyses—including duodenal histomorphology, hepatic and duodenal mRNA expression, and cecal bacterial populations. Crypt depth was significantly (p < 0.5) shortest in AJ when compared to APo and APu. APo and APu soluble extracts significantly improved villi surface area compared to NI and H2O control groups. The highest count of Paneth cells per crypt was observed in APo as compared to all groups. In addition, the expression of brush border membrane micronutrient metabolism and functional proteins varied between treatments. Lastly, Lactobacillus cecal microbial populations increased significantly in the AJ group, while AJ, APu, and APu increased the abundance of Clostridium (p < 0.5). Ultimately, these results indicate the potential of Empire apple pomace to improve host intestinal health and the gut microbiome.

Speaker Bio: Cydney Jackson completed her bachelor’s degree in Food Science at Alabama Agricultural & Mechanical University where she studied the antioxidant capacity of portabella mushrooms. She is currently a Ph.D. student in Dr. Elad Tako’s laboratory utilizing the broiler chicken model to investigate the interrelation between dietary zinc physiological status, vitamin A, and the gut microbiome. Cydney has also led research projects investigating the effects of Empire apples and soy flour-enriched traditional bread on intestinal health and the gut microbiome.

Caroline Motzer

MS Candidate, Wiedmann Lab

Method Development for Industry Regarding Isolation and Tracking of Thermoduric,

Non-spore forming, Defect causing Bacteria in Dairy

Abstract: Bacterial contaminants enter the dairy product supply chain through a variety of avenues from farm to processing. These bacterial contaminants represent diverse groups, many of which can cause deterioration in dairy product quality, including in cheese, yogurt, fluid milk, and others. Of particular importance to cultured dairy products such as cheese and yogurt are thermoduric bacteria and Nonstarter Lactic Acid Bacteria (NSLAB), which can survive moderate to severe heat treatments such as pasteurization. In the cheddar cheese industry, of which nearly 1.3 billion lb of NY raw milk went toward the manufacture of in 2020, slits and cracks caused by thermoduric bacteria and NSLAB is one of the most common quality defects. To that end, the 3 objectives of this study are Objective 1. Development of testing methods for detection of key thermoduric and NSLAB populations known to cause dairy product defects, Objective 2. Compare isolates obtained to “finished product issues” caused by select thermoduric and non-starter lactic acid bacteria and Objective 3. Knowledge and method transfer to allow large cheese manufacturers and other stakeholders to reduce spoilage issues due to thermoduric or non-starter lactic acid bacteria. The current state of the project is focused Objective 1, specifically surrounding thermoduric bacteria. 9 Genera were selected based on their survival in lab pasteurized milk and their ability to cause defects. From there, using the in-house Food Safety Laboratory library of strains, 40 strains from these 9 genera were selected based on genetic differences to use for method development for isolation from milk broth. Methods being tested are a combination of 4 time and temperature treatments, 2 media and 3 incubation times. Due to the ongoing nature of this study, results are currently not finalized. Once a method for isolation has been established, industry can use said method(s) to test raw milk at different points in the dairy continuum to identify avenues of contamination and identify what bacterial contaminant is causing defects.

Speaker Bio: Caroline Motzer is an MS Student in the Wiedmann Lab studying new methods for industry to isolate defect-causing thermoduric bacteria in dairy products. Additionally, she is researching the economics of Listeria environmental monitoring programs in dairy facilities and possible food safety uses for AI in controlled environment agriculture. Previously, Caroline served as Quality Assurance Food Scientist and SQF Practitioner for plant-based meat tech company, Rebellyous Foods. Prior to that, she worked as an assistant grower for hydroponic, urban agriculture start-up, Farmbox Greens. She received two B.S degrees from Cornell University in 2019 in Agriculture Sciences and International Development and Rural Agriculture.

Rory Wang

Ph.D. Candidate, Worobo Lab

Validation of Cryptosporidium parvum Inactivation in Apple Juices: Moving away from Animal Models

Abstract: Cryptosporidium parvum is a pertinent pathogen in apple juices and the FDA requires validation against C. parvum in apple juices or products that contain apple juice blend. Gold standard validation of parasite inactivation in juices relies on animal models, which can be costly and difficult to perform. This study explores the validity and practicality of several animal-free methods including human cell line-qPCR model, human cell line-live/dead qPCR model and simple sucrose centrifugation-qPCR model.

Speaker Bio: Rory Wang is a third-year PhD student in Randy Worobo's research group. He attended Iowa State University for his B.S. in food science and attended Washington State University for his M.S. in food microbiology. His current research focuses on advancing microbial aspects of high-pressure processing applications in juices. He also enjoys working on extension and outreach projects, and he serves as the current DEI liaison for the Community Outreach Committee in the department.