Regrinding ground beef in the meat laboratory located in the Northwest Missouri State University.
Author: Ashley Paulette Rivera Pitti | Major: Animal Science | Semester: Spring 2025
I am Ashley Rivera, a senior Animal Science major from Bumper College. Since Spring 2025, I have been working with Dr. Derico Setryabrata, from the department of animal science. Our focus for this project is meat quality, specifically ground beef color stability and shelf life. As a result of this and previous research experiences, I’d like to pursue a master’s degree in meat science following graduation.
Color deterioration is a major meat quality defect that can lead to product rejection, reduced retail sales, and increased waste. Ground beef discoloration is closely tied to its production. During manufacturing, the meat is exposed to oxygen, prooxidants, and microorganisms, which can compromise muscle integrity, accelerate discoloration, and reduce shelf life. Because consumers often judge and determine the freshness and safety of meat products based on their appearance, it becomes crucial to minimize their discoloration to reduce meat waste and prevent commercial losses. Internal factors such as muscle enzymes and external factors like microbial exposure influence meat color quality over time. This research project aims to investigate how microbial populations from different processing facilities interact with the meat’s native microbiome (the mix of bacteria found in meat) and its impact on ground beef color quality and shelf life.
In my sophomore year, I took a class taught by Dr. Setryabrata. By introducing his professional path, I learned about a new – at least for me – discipline, meat science. After some volunteering opportunities at the animal science meat laboratory, I rapidly developed an interest in learning more about meats. I am beyond grateful that Dr. Setyabrata welcomed me to his team. Since then, I have immersed myself in multiple projects, primarily focusing on meat quality, which I have thoroughly enjoyed.
As a result of a study on color quality, I realized how complex yet interesting and important this topic is. Again, consumers often make purchasing decisions based on appearance, so targeting meat discoloration is crucial. Additionally, ground beef is one of the top beef products at the retail level due to its convenience. The manufacturing processes of ground beef and its internal biochemical enzyme reactions significantly influence its retail performance.
Dr. Setyabrata encouraged me to apply for this research grant to further explore how microbial populations and meat enzymes interact and affect color quality – a topic I am eager to investigate.
Although this study is not finalized yet, I expect to see differences in microbial communities between production and processing facilities, which may influence meat enzyme reactions differently. Even when all factors are accounted for such as – pick-up time, travel duration, temperature, product age, source plants, processing equipment, and time – there remain aspects that could vary either at production or processing stages, potentially affecting outcomes.
While I have participated in previous research projects, being responsible for my own project came with some nervousness, especially as I learned new experimental procedures that relied heavily on human accuracy and consistency. Along the way, I’ve had some challenges, yet the rewarding feeling of obtaining satisfactory results and overcoming those difficulties has been totally worth it.
In executing quality assays, specifically the Metmyoglobin Reducing Ability (MRA) test, the first step involved cutting a piece from the ground beef loaves into square samples and submerging them in a sodium nitrite solution to induce oxidation. The samples needed to discolor completely for an accurate evaluation of the metmyoglobin-reducing ability of the meat, which required taking color scans before and after incubation.
At first, I struggled to cut perfectly compact and homogeneous ground beef squares. This inconsistency affected how well the samples stood up in the solution and whether they fully oxidized. Some squares were cut too thick, causing the solution to overflow, while others were too thin and broke easily, complicating the process. Dr. Morgan Denzer, who was collaborating in the lab at the time, helped me devise a better strategy for achieving consistent squares and ensuring complete oxidation. I discovered that I had been too gentle with the knife and careless with my cuts, which negatively impacted the final shape of the squares. By adjusting my handling techniques, I was able to produce more consistent samples that performed well in the sodium nitrite solution. This experience taught me that practice makes perfect—something I found to be very true! I am very grateful that Dr. Denzer was available to guide me throughout this process and help me build my confidence.
Microbial analysis was also essential for this project, as it quantified the microbial communities (aerobic and lactic acid bacteria) present in the samples. Contaminating these samples could result in misleading associations among different microbial populations, hindering our ability to determine and classify their influence on the meat’s native microbiome. Not only did I feel the pressure of this responsibility, but I was also anxious about the meticulous steps required to extract the meat rinsate and plate it, fearing that any mistake could disrupt the entire analysis. Fortunately, Dr. Setyabrata was there to train me and ensure that I took precautions to avoid contamination. By wearing appropriate PPE, sterilizing utensils, properly diluting samples, and plating gently, I was able to overcome my initial nervousness and gain confidence. Once I completed this initial phase, my progress became more fluid and enjoyable.
Dr. Setyabrata has played a crucial role in my research journey. He was the first faculty member to believe in, involve, and guide me as a sophomore who was unsure of her future professional path. I have been inspired by Dr. Setyabrata’s passion and dedication to research and his commitment to exploring viable solutions for issues that impact meat quality and safety. As I continue my academic journey and work towards a career in research by applying for a master’s program in meat science, I hope to contribute to providing wholesome meat products and satisfactory eating experiences for consumers while also protecting the environment and benefiting producers.