Research Project: Reducing Postharvest Loss and Improving Fresh Produce Marketability and Nutritive Values through Technological Innovations and Process Optimization

Location: Food Quality Laboratory

2025 Annual Report

Objectives
Objective 1. Enhance key organoleptic and nutritional qualities of major horticultural crops using emerging production and post-harvest handling practices. Sub-obj. 1A. Improve food quality and nutrition, and harvesting efficiency for vegetables grown via controlled environment agriculture (CEA). Sub-obj. 1B. Develop novel technologies to support NASA’s mission in growing microgreens in space. Objective 2. Reduce post-harvest loss and waste and enhance marketability of fresh produce. Sub-obj. 2A. Non-destructive monitoring of produce quality and maturity via a paper sensor. Sub-obj. 2B. Improve quality and shelf life of fresh produce through collaborative breeding and cultivar selection. Sub-obj. 2C: Predicting consumers’ preferences for fruits and vegetables through advanced analyses of digital imagery and emotions. Objective 3. Improve product quality and sustainability through novel fresh-cut processing technologies and process optimization. Sub-obj. 3A. Develop novel fresh-cut produce wash and disinfection technologies for comprehensive improvement in food quality and safety. Sub-obj. 3B. Determine chemical profile of fresh-cut produce wash water in support of cost-effective water treatment and reuse. Sub-obj. 3C. Assess the potential use of nanoparticle coatings on the contact surface of equipment to optimize fresh-cut processing.

Approach
This project takes an integrated and holistic approach to tackle major food security problems by supporting efficient growth and harvesting of nutrient-dense food products and reducing post-harvest food loss and waste. This project consists three objectives. In objective 1, we will investigate the effect of light wavelength, intensity, and photoperiod on the growth, sensorial quality, and phytonutrient content of specialty vegetables. We will develop mechanical devices to facilitate harvesting of microgreens while minimizing tissue damage. We will also develop and/or evaluate soil mixes and soil-less growth media for seed fixation in microgravity. In objective 2, our team of scientists will collaborate with ARS breeders to identify lettuce cultivars resistant to enzymatic browning and having improved post-harvest quality and shelf life. We will continue collaborating with our university partner (and co-inventor) to advance our patent-pending paper sensor array for nondestructive quality evaluation. In objective 3, we will work with our industry partners to further develop, optimize, and commercialize our patented produce washing and disinfection technology. We will develop and optimize a novel in-flight washing system to improve the food quality and safety of fresh-cut products. This will be a continuation and expansion of the patented in-flight washing technology developed under a previous project. We will also investigate the major chemical components of fresh-cut produce wash water and develop approaches to support safe and cost-effective water reuse. Specifically, we will identify major compounds present in produce; their release during cutting; their reactivity with free chlorine during different washing stages; how such reaction contributes to the loss of free chlorine in wash water, and to difficulties in maintaining adequate chlorine levels; the type and amount of harmful disinfectant byproducts thus produced during washing; and effective methods to remove or mitigate the chemical oxygen demand (COD) and chlorine demand (CLD) in wash water during fresh-cut processing.

Progress Report
Objective 1 “Enhance key organoleptic and nutritional qualities of major horticultural crops from emerging production and post-harvest handling practices.” In support of Sub-objective 1A, we designed and fabricated an ultrasonic cutting system and tested its application on harvesting broccoli and arugula microgreens. We also completed and tested the design of a harvesting device for microgreens. In support of Sub-objective 1B, we invented a novel 3D microgravity simulator featuring multiple stages and multispectral modulation capacity. This unique instrument allows simultaneous studies on the response of plant or microorganism samples to a diversity of precisely controlled light regimes. This patent-pending technology fills a critical void in space biology research. We have developed multiple forms of soilless growth substrates including hydrogels, aerogels, and ion foams from natural polymers (e.g., polysaccharides) and wood waste materials. The lightness, biodegradability, biocompatibility, high water retention capacity, and desirable plant growth performance make those novel materials an attractive alternative to mineral-based and non-sustainable substrates such as Styrofoam, peat moss, and Rockwool. This technique has prompted an ongoing study on the high-throughput growth substrate screening empowered by robotic- and machine learning, which is being conducted in collaboration with the Autonomous Materials Discovery Lab at the University of Maryland. Third, we started new research on the light modulation of growth, sensory properties, and postharvest attributes of leafy greens in controlled environment conditions. Results with basil plants grown under supplementary blue, far-red, and blue + far-red lights exhibited distinct canopy sizes, stem lengths, leaf thicknesses, and leaf colorations. Furthermore, light treatments altered the aroma of basil and improved post-harvest performance. Therefore, specific wavebands of light can be used to alter basil growth and produce distinct aromatic profiles. We also developed a novel technology that supports seed germination and plant growth in space- and resource-limited environments. We also designed and fabricated a novel self-assembling breathable vascular micro-network as a microgreen growth medium intended for microgravity and water-limited conditions. Objective 2 “Reduce Post-harvest Loss and Waste and Enhance Marketability of Food Products.” In support of Sub-objective 2A, we tested a novel chromogenic sensor array for detecting plant pathogens affecting produce and floral plants. Among the 21 dyes tested, 9 responded to the volatile organic compounds (VOCs) from Ralstonia. These results will facilitate further development and optimization of the sensor array as a non-destructive surveillance and early detection tool for plant pathogens. We developed an array of sensors with varying specificity and sensitivity for non-specific and multi-dimensional nondestructive measurements of volatile compounds with a wide range of odor characteristics. We integrated machine learning methods with an electronic-nose system for fresh produce quality monitoring and adulteration applications. We broadened the research scope for the identification of browning resistant romaine lettuce cultivars and further investigated (in collaboration with ARS-Salinas researchers) the genome-wide association of browning discoloration in cut lettuce. Sub-objective 2B was previously redirected to new research on developing a novel and efficient technology that advances sciences across two biological kingdoms – by pelleting and protecting partial peanut seeds using crab shell waste from the seafood industry. At the request of the peanut industry stakeholders and USDA leadership in the Southeast Area (SEA), we developed an anti-aflatoxin seed coating for peanuts using novel microencapsulation technology. In specific, the novel technology aims to enable sustained release of Afla-Guard® (an ARS-patented bio control of the fungus that produce mycotoxin in peanuts). Our team developed the essential equipment and enabled the successful completion of this project in a short period of time (three weeks vs years conventionally). Over 1,440 pelleted and treated seeds (12 treatments) were prepared and shipped to the ARS peanut experts in SEA for scale up studies. In support of Sub-objective 2C this year we produced a diverse collection of over 200,000 data points based on over 80 sensory test participants to form a basis for statistical analysis and eventually machine learning that could support prediction of consumers for fruits and vegetables. We refined our understanding of consumer behavior in online grocery shopping, particularly concerning mini cucumbers, strawberries and apples, by analyzing eye tracking data related to visual imagery and product information. Additionally, fruit packaging research progressed by evaluating consumer attention to different packaging types and the relationship between liking scores and color analysis in online settings. Objective 3: “Improve product quality and sustainability through novel fresh-cut processing technologies and process optimization.” In support of Sub-objective 3A, we developed and tested the second prototype of our in-flight washer (IFW) for organic matter removal and bacterial inactivation. In collaboration with industry collaborators we assessed the performance of this second IFW prototype, and systemically characterized chlorine disinfection results, supported with laboratory tests. The industry collaborators considered this IFW innovation a “game changer” for fresh-cut produce wash system and operation. Although the IFW was designed for early removal of organic matter prior to flume washing and to minimize cross contamination, our group found that intervention of the cutting/chopping/dicing step prior to IFW would further improve organic matter removal further lowering the bacterial population in cut produce prior to flume washing. Results showed that cutting under chlorinated water injections and different spray patterns, significantly decreased bacterial load and significantly reduced organic load in fresh-cut produce prior to IFW. The cutting-IFW intervention is a novel approach that has not been reported previously. We are currently providing four large produce processors with science-based information on the importance of cutting intervention and pre-wash rinsing to reduce organic matter and minimize cross-contamination. We also promoted the design and purpose of this novel technology to produce growers and processors, including Church Brothers Farms and Fresh Express LLC. In support of Sub-objective 3B, we collaborated with the Grower-Shipper Association of Central California and four major produce growers and processors to collect and analyze data from their commercial processing lines. In support of Sub-objective 3C, we worked with scientists from Texas A&M to optimize the formula of nanoparticle coatings on the contact surface of equipment to minimize biomass accumulation and prevent microbial biofilm formation. We also developed novel biobased packaging materials for cucumbers and avocado.

Accomplishments
1. Developed and assessed use of ultrasonic cutting systems as microgreens harvest device. Microgreen growers need efficient harvesting methods to maintain crop quality and extend shelf life, ensuring profitability and consistent supply. However, traditional harvesting techniques often cause significant tissue damage, leading to rapid spoilage and reduced marketability for these delicate crops. ARS scientists in Beltsville, Maryland, addressed this challenge by developing and accessing a novel ultrasonic cutting system for harvesting microgreens. This system significantly reduces tissue damage during harvest, leading to a prolonged shelf life. This advancement in knowledge demonstrates that ultrasonic technology can be effectively applied to improve post-harvest quality of specialty crops. This technology will offer microgreen growers and processors a more efficient and gentle harvesting solution, increasing their marketable yield and reducing post-harvest losses.

2. Developed and evaluated a novel self-assembling breathable vascular micronetwork as a microgreen growth medium for microgravity and water-limited conditions. Producing food in water-limited and microgravity conditions presents challenges for space flight. ARS scientists in Beltsville, Maryland developed a vascular hydrogel that exhibits ultrahigh water retention and structural integrity. This hydrogel supports amaranth seed germination with significantly improved positional stability under microgravity and without continued need for bulk water. This research also included the development of small and large scale spray-freeze-drying systems for microencapsulation of active ingredients for targeted delivery. In addition to improving plant growing conditions in microgravity and water-limited conditions, these techniques have potential applications for drug, cosmetic, and other food product development.

3. Developed a novel technology that advances sciences across two biological kingdoms by pelleting and protecting partial peanut seeds with crab shell waste from the seafood industry. A significant obstacle to peanut production is widespread aflatoxin contamination, which poses both health risks and economic losses, compounded by the environmental burden of accumulating seafood waste. ARS scientists in Beltsville, Maryland developed a novel technology to tackle both issues: a seafood waste-based, microcapsule-incorporated anti-aflatoxin seed coating for peanut kernels using crab shell waste. This innovation reduces aflatoxin contamination while providing sustainable use for industrial waste. This significantly advances our understanding of integrating agricultural and industrial waste streams for a circular economy. These results are crucial for farmers, consumers, and the seafood industry. Our technology offers a cost-effective, eco-friendly alternative to synthetic treatments, enhancing peanut safety and marketability. It also transforms waste into a valuable resource, benefiting both agricultural and seafood sectors.

4. Integration of eye-tracking, biometrics and sensory science to study consumer preferences for fresh produce in online settings. Increasing fruit and vegetable consumption can improve diet quality and reduce risk for disease. Gaining a better understanding of how consumers make choices about which fruits and vegetables to consume can support guidance to increase consumption. ARS scientists in Beltsville, Maryland, pioneered the use of eye-tracking systems to gain objective data to determine how consumers visually select fruits and vegetables. Using this system, data on consumer assessment for diverse fresh products revealed the key importance of brand and packaging design, and food color (intensity and uniformity). Additional testing with apples revealed how expectations for high quality could differ when consumers are reminded of the flavor of the product. This research with biometric devices provides valuable insights for optimizing product presentation and marketing strategies within the fresh produce industry, ultimately enhancing consumer satisfaction.

5. Modified cutting system in a fresh-cut produce washing system to reduce bacteria levels and minimize cross-contamination. Washing during postharvest handling of produce is commonly used in the fresh-cut industry. It is a critical step to remove impurities from produce and reduce bacteria load, while also preventing cross contamination. However, challenges remain due to diverse conditions in the crop field. ARS scientists in Beltsville, Maryland identified the cutting step in the produce packing house as a vulnerable step for further accumulation of pathogens and contamination. However, injecting chlorinated water simultaneously while cutting not only cleaned the blades, but it also decreased organic load and bacterial population prior to pre-wash rinsing. These findings provide science-based information to fresh produce processors revealing that to improve food safety, chlorinated water injections in the cutter should be added as a step for both cleaning/sanitizing and processing.

Review Publications
Zhou, B., De Frias, J.A., Luo, Y., Fonseca, J.M., Feng, H. 2025. Impact of power ultrasound on the quality of leafy green produce through a multifrequency, multimode, modulated system. Ultrasonics Sonochemistry. 113:107221. https://doi.org/10.1016/j.ultsonch.2024.107221.
Gu, G., Zhou, B., Yang, Y., Nou, X., Millner, P.D., Zhang, B., Luo, Y. 2025. Microbial profiles of commercially packaged baby spinach from hydroponic controlled environment agriculture and soil-based open field production. Food Control. 175. Article 111198. https://doi.org/10.1016/j.foodcont.2025.111198.
Zhou, B., Luo, Y., Liu, Z., Sun, J., Fonseca, J.M. 2025. Programmable Light-Emitting Diode (LED) lighting enhances growth and nutrients of red cabbage microgreens in controlled environments. Journal of Agriculture and Food Research. 22. Article e102097. https://doi.org/10.1016/j.jafr.2025.102097.
Oehler, M.A., Kelly, N., Fonseca, J.M., Evensen, E., Park, E., Gu, G., Teng, Z., Luo, Y. 2025. Influence of supplementary blue and far-red light on the morphology and texture of Ocimum basilicum L. grown in controlled environments. Horticulturae. 11(3). Article e287. https://doi.org/10.3390/horticulturae11030287.
Luciano-Rosario, D., Castro, J., Peter, K., Cox, K., Gaskins, V.L., Fonseca, J.M., Jurick Ii, W.M. 2024. Mold in, mold out: Storage bins harbor viable inoculum that can be reduced using novel sanitation methods to manage blue mold decay of apples. Postharvest Biology and Technology. 221. Article e113323. https://doi.org/10.1016/j.postharvbio.2024.113323.
Park, E., Luo, Y., Bornhorst, E., Simko, I., Trouth, F.J., Fonseca, J.M. 2024. Leveraging observations of untrained panelists to screen for quality of fresh-cut romaine lettuce. Horticulturae. 10(8):830. https://doi.org/10.3390/horticulturae10080830.
Bornhorst, E.R., Luo, Y., Park, E., Zhou, B., Turner, E.R., Teng, Z., Simko, I., Fonseca, J.M., Trouth, F.J. 2024. In search of optimum fresh-cut raw material: Using computer vision systems as a sensory screening tool for browning resistant romaine lettuce accessions. Horticulturae. 10(7). Article e10070731. https://doi.org/10.3390/horticulturae10070731.
Bartholomew, H.P., Gottschalk, C.C., Cooper, B., Bukowski, M.R., Yang, R., Gaskins, V.L., Luciano-Rosario, D., Fonseca, J.M., Jurick Ii, W.M. 2024. Omics-based comparison of fungal virulence genes, biosynthetic gene clusters, and small molecules in penicillium expansum and penicillium chrysogenum. The Journal of Fungi. 11(1). Article e14. https://doi.org/10.3390/jof11010014.
Evensen, E., Teng, Z., Mao, Y., Li, Y., Ortiz, I., Chen, P., Yang, T., Wang, Q., Fonseca, J.M., Luo, Y. 2025. Optimizing microgreen cultivation through post-crosslinked alginate-gellan gum hydrogel substrates with enhanced porosity and structural integrity. International Journal of Biological Macromolecules. 309(3). Article e142905. https://doi.org/10.1016/j.ijbiomac.2025.142905.