In this post, Mohit Verma, an associate professor of agricultural and biological engineering, and a member of Birck Nanotechnology Center, the Purdue Institute for a Sustainable Future, the Purdue Institute for Drug Discovery, and the Purdue Institute for Inflammation, Immunology and Infectious Disease, discusses his research “A portable, easy-to-use paper-based biosensor for rapid in-field detection of fecal contamination on fresh produce farms” which was recently published in Biosensors and Bioelectronics with the support of the The Center for Produce Safety, the California Department of Food and Agriculture, and the U.S. Department of Agriculture.
What did you want to know?
In this research, we aimed to develop and validate a portable, easy-to-use biosensor capable of quickly and accurately detecting levels of potential fecal contamination in the field. Traditionally, microbial contamination tests involve collecting field samples and sending them to specialized laboratories. This conventional process is expensive, time-consuming, typically requiring 24–48 hours, and depends on highly trained laboratory technicians, making it impractical for regular monitoring by producers. Additionally, delays in testing can affect the produce’s freshness and further shorten its already limited shelf life. To address these challenges, we developed an innovative paper-based biosensor to rapidly and reliably detect Bacteroidales, a bacterial group commonly used as an indicator of fecal contamination. We sought answers to key questions: Could our biosensor deliver accurate results directly in the field, eliminating the need for laboratory infrastructure? Would the sensitivity of our biosensor match that of traditional laboratory assays, such as quantitative polymerase chain reaction (qPCR)? Additionally, we aimed to integrate all necessary components into a single, portable device to improve user-friendliness. Ensuring ease of use for non-specialists, such as farm operators and growers, was a key priority for us to make the technology implementable in real-world farming scenarios, allowing faster and more informed decision-making regarding food safety.
What did you achieve?
The primary achievement of our research is the successful development and field validation of FARM-LAMP, an integrated, portable, paper-based biosensor system designed for rapid detection of fecal contamination indicators on fresh produce farms. We demonstrated the implementation of FARM-LAMP in the back of a van on a farm. This innovative platform seamlessly integrates key components—fluid handling, precise reaction heating, and automated colorimetric imaging analysis—into a compact, user-friendly device. FARM-LAMP demonstrated high sensitivity, detecting as few as 3 copies of Bacteroidales per square centimeter, a performance comparable to conventional laboratory-based testing methods (e.g., qPCR). Notably, when deployed directly on commercial lettuce farms, our device showed a 100% concordance rate with results from qPCR tests conducted in the lab. Moreover, FARM-LAMP significantly reduced turnaround time, producing quantitative contamination risk assessments within just one hour of sample collection. By incorporating simplified fluid handling and automated image processing, we eliminated much of the complexity traditionally associated with microbial testing, allowing non-specialists, such as farm personnel, to operate the system with ease. This study represents the first successful field demonstration of a portable biosensing technology for fresh produce farming, paving the way for broader adoption of rapid, on-site microbial safety testing.
What is the impact of this research?
This research addresses important global issues related to food safety and public health. Microbial contamination, particularly fecal contamination, remains a major public health threat, causing frequent foodborne illness outbreaks linked to fresh produce. These outbreaks not only pose serious health risks to consumers but also result in economic losses for farmers and retailers, as well as significant food waste. Our research offers a practical, scalable solution by enabling rapid, accurate, and cost-effective contamination testing directly at farm sites. The accessibility and ease of use of the FARM-LAMP system empower farmers—regardless of their resources or technical expertise—to swiftly detect contamination risks before produce reaches consumers. By reducing the likelihood of foodborne illness outbreaks, this technology enhances public health outcomes and strengthens consumer confidence in food safety. Furthermore, the portable and low-cost design of FARM-LAMP makes it equally valuable in both developed nations and resource-limited agricultural settings, where access to laboratory facilities is often scarce. By improving food safety, reducing waste, and increasing accessibility to reliable testing, this research contributes meaningfully to global sustainability and public health, ensuring cleaner, safer fresh produce for all.