June 29, 2026
Study shows how an essential process can be made faster, more affordable and accessible, benefiting agricultural producers, regulators and consumers.
At Mizzou Engineering, we are continually unlocking practical solutions to real-world problems faced by communities and industries here in Missouri and around the world.
A new, multidisciplinary study from Mizzou researchers points to a simpler, faster way to test milk for bacterial contamination — an advance that could ultimately lower costs for food producers and improve access to safety testing across the industry.
At its core, the work, published in the Journal of Microbiological Methods, addresses a practical problem: Regulatory agencies such as the Food and Drug Administration (FDA) and the Department of Agriculture (USDA) set strict limits on how much bacteria can be present in milk and other food products.
But the standard methods used today are time-consuming, labor-intensive and require significant lab resources. Under these conditions, producers often ship products assuming they meet safety thresholds, only to face costly recalls if later tests reveal problems.
“The question is, can you simplify that process and still get the numbers with confidence?” said Associate Professor Shramik Sengupta, primary investigator on the study. “The answer is yes.”
Collaborative community
The idea for the study was born of Sengupta’s ongoing academic collaboration with Azlin Mustapha, a professor of food science in the College of Agriculture, Food and Natural Resources (CAFNR). The two had previously collaborated on using electrical techniques for microbiological studies.
“My office was in the Agricultural Engineering building, which adjoins Eckles Hall where Dr. Mustapha works,” Sengupta said. “My students took her classes. I served on her PhD students’ committees, and she served on mine.”
Mustapha recalls discussing ideas to rapidly detect pathogens in food using a microfluidic impedance-based platform developed by Sengupta and developing a miniaturized most probable number (MPN) technique, a standard detection method for water and milk quality
“Current standard detection methods for food, including the MPN, can be very time- and labor-intensive, requiring expensive materials and sometimes specialized instruments,” she said. “Based on results from some preliminary experiments we conducted, we believed that we could achieve equivalent results as a standard MPN by using very small quantities of samples.”
Sengupta and Mustapha recruited graduate researchers from the Department of Chemical and Biomedical Engineering and the Department of Food Science to simplify testing using much smaller amounts of liquid and fewer steps.
The MPN method relies on serial dilution: gradually diluting a sample repeatedly, using multiple test tubes each time, and measuring the bacterial growth across a range of concentrations. The process is time-consuming and prone to handling errors.
The researchers diluted the sample just one time and pipetted varying amounts into a microplate, which looks a bit like a miniature ice cube tray. Instead of creating weaker samples step by step, they used smaller and smaller sample volumes from the same diluted liquid. They found that the small samples produced reliable estimates of bacterial levels with far less work.
Lab-on-a-chip
The study demonstrated that a small-volume, low-effort format delivers results similar to current tests and does it faster. Faster testing could help food producers respond more quickly to potential contamination issues, reducing delays and costs and improving confidence across the supply chain.
“If you reduce the costs, you help smaller producers who, as of now, cannot devote as much money into testing, make it possible for them to meet the USDA standards more consistently,” Sengupta said.
This study is just the first step toward a larger vision. Sengupta’s team ultimately aims to move this kind of testing off the lab bench and onto a tiny, automated lab-on-a-chip.
For now, the team’s research serves as proof of concept, supporting a pending USDA grant proposal that would fund development of the technology.
The project reflects the research environment at Mizzou, where engineers, microbiologists and food scientists work closely across disciplines, from engineering and agriculture to veterinary and medical programs — all located on one campus.
This environment allows ideas to move quickly from concept to application, with researchers able to access expertise, facilities and even biological materials with relative ease.
“We have CAFNR, the College of Veterinary Medicine, and the School of Medicine,” Sengupta said. “Here, you can step out of your office and find another opportunity to advance your research. For the type of work that I seek to do, it is super awesome.”
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