Location: Food Quality Laboratory
2018 Annual Report
Objectives
1. Evaluate the effects of pre-harvest production and post-harvest processing and storage treatments on fruit flavor, maintenance and/or enhancement in diverse accessions and breeding lines of Capsicum pepper, Malus sieversii apple, and blueberries; determine underlying molecular mechanisms controlling flavor quality.
2. Evaluate technologies to maintain the quality and marketability of fresh and fresh-cut produce through integrated microbiological and physiological approaches and innovations in post harvest handling, sanitation, and modified atmosphere packaging technology.
Approach
Mature produce from 30 to 240 accessions of non-cultivated and/or cultivated accessions of Capsicum peppers, Malus sieversii apple, and rabbiteye blueberry will be evaluated for flavor and nutritional quality-related substances using established gas chromatography, liquid chromatography and sensory methods and for shelf stability and overall marketability. Additional species to be studied include lettuce, tomatoes, strawberries, raspberries, and assorted microgreen.
Progress Report
Marketability and consumer preference of strawberry varieties determined via sensory evaluation with trained panels. The United States is the largest strawberry producer in the world, with around 1,500,000 tons of strawberries produced annually. Identifying sensory attributes that are most preferred by consumers will help the strawberry industry to strategize their breeding and production programs to maximize their profits and minimize labor and environmental inputs, while providing palatable strawberries for human consumption. Using descriptive analysis conducted by trained panels, ARS scientists in Beltsville, Maryland, evaluated sensory attributes of different strawberry varieties grown in the east coast region. The panelists described and differentiated strawberries with twenty-five attributes, including the intensity and acceptability of appearance, flavor, and texture characteristics. Instrumental analysis of the quality parameters including color, texture, titratable acidity, and soluble solids supplemented the sensory results. This progress report reflects the first-year research activities in this project. Consumer panel evaluation is planned for FY2019.
Developed a computer vision and image analysis method to detect and quantify quality defects in fresh-cut produce. Image processing technology is a powerful tool to visualize and quantity product detects and appearance variations. However, its application in the agricultural industry lags other industries and scientific disciplines. ARS scientists in Beltsville, Maryland, developed and applied new image analysis tools to detect and quantify important plant physiological disorders, including the extent of a water soaking defect in sliced watermelons and the browning severity in cut lettuce leaves. High resolution images of fresh-cut produce were taken under controlled lighting and analyzed using a smart segmentation computer software. Using this technology, researchers successfully determined the best packaging treatments for cut watermelon that led to least amount of water soaking appearance and identified lettuce varieties that are least prone to browning, and best for fresh-cut processing.
Accomplishments
1. Safe and effective reuse of fresh produce wash water. Reusing and reducing fresh-cut vegetable wash water is a necessity for sustained industry growth and a reduced environmental footprint. However, organic matter accumulated in the reused wash water can lead to a loss of anti-microbial efficacy for chlorine disinfectant and compromise food quality and safety of the washed products. ARS scientists in Beltsville, Maryland, conducted ground-breaking research into the roles of the major chemical components of organic matter in relation to chlorine demand and chemical oxygen demand, the two most important factors for chlorine sanitizer replenishment and water treatment. Results demonstrated that proteins and peptides are major contributors to the loss of chlorine efficacy needed for bacterial control in reused wash water. Results further showed sugars are the most important factor in the chemical oxygen demand that is important for developing effective wash water treatment and recycling programs. These findings provide essential information for the vegetable processors to develop safe, effective, and economical chlorine replenishment strategies and wash water reuse programs.
2. An injection and inline mixing system for chlorine control during fresh-cut produce wash operation. Washing fresh-cut produce via a non-immersive technology using a series of single pass water sprayers is a new industry development designed to reduce water-mediated bacterial transfer caused by the reuse of wash water. However, the lack of an inline chlorine dosing and mixing system with targeted free chlorine levels hinders the technology advancement in this field. ARS scientists in Beltsville, Maryland developed a new sanitizer in-line mixing system, which enables automated inline dosing and mixing for free chlorine and acidulants. Free chlorine can be adjusted between 0 and 50 mg/L with a pH at any level using this new system. This upper limit is far beyond the capability of currently available commercial systems, which cannot exceed 20 mg/L. This system gives the user more flexibility to run experiments with different concentrations of sanitizers in a limited space, without using a large water reservoir. The control system will be especially useful for food processors who require dosing and monitoring of free chlorine at higher concentrations with space constraints.
Review Publications
Luo, Y., Zhou, B., Van Haute, S., Nou, X., Zhang, B., Teng, Z., Turner, E.R., Wang, Q., Millner, P.D. 2017. Association between bacterial survival and free chlorine concentration during commercial fresh-cut produce wash operation. Food Microbiology. 70:120-128.
Park, E., Luo, Y., Marine, S.C., Everts, K.A., Micallef, S.A., Bolten, S.J., Stommel, J.R. 2018. Consumer preference and physicochemical evaluation of organically grown melon. Postharvest Biology and Technology. 141:77-85.
Mei, L., Teng, Z., Zhu, G., Liu, Y., Zhang, F., Li, Y., Guan, Y., Luo, Y., Chen, X., Wang, Q. 2017. Advanced materials interfaces. ACS Applied Materials and Interfaces. 9(40):3529-3530.
De Frias, A.J., Luo, Y., Zhou, B., Turner, E.R., Millner, P.D., Nou, X. 2018. Minimizing pathogen growth and quality deterioration of packaged leafy greens by maintaining optimum temperature in refrigerated display cases with doors. Food Control. 92:488-495.
Lu, Y., Dong, W., Yang, T., Luo, Y., Wang, Q., Chen, P. 2017. Effect of preharvest CaCl2 spray and postharvest UV-B radiation on storage quality of broccoli microgreens, a richer source of glucosinolates. Journal of Food Composition and Analysis. 67(1):55-62. https://doi.org/10.1016/j.jfca.2017.12.035.
Gu, G., Ottesen, A., Bolten, S.J., Ramachandran, P., Reed, E., Rideout, S., Luo, Y., Patel, J.R., Brown, E., Nou, X. 2018. Shifts in spinach microbial communities after chlorine washing and storage at compliant and abusive temperatures. Food Microbiology. 73:73-84. https://doi.org/10.1016/j.fm.2018.01.002.
Teng, Z., Luo, Y., Alborzi, S., Zhou, B., Chen, L., Zhang, J., Zhang, B., Millner, P.D., Wang, Q. 2017. Investigation on chlorine-based sanitization under stabilized conditions in the presence of organic load. International Journal of Food Microbiology. 67:150-157.
Zhou, B., Luo, Y., Bauchan, G.R., Feng, H., Stommel, J.R. 2017. Visualizing pathogen internalization pathways in fresh tomatoes using MicroCT and confocal laser scanning microscopy. Food Control. 85:276-282.
Van Haute, S., Luo, Y., Sampers, I., Mei, L., Teng, Z., Zhou, B., Bornhorst, E., Wang, Q., Millner, P.D. 2018. Can UV absorbance rapidly estimate the chlorine demand in wash water during fresh-cut produce washing processes? Postharvest Biology and Technology. 142:19-27. https://doi.org/10.1016/j.postharvbio.2018.02.002.
Nyarko, E., Kniel, K.E., Zhou, B., Millner, P.D., Luo, Y., Handy, E.T., East, C.L., Sharma, M. 2018. Listeria monocytogenes persistence and transfer to cantaloupes in the packing environment is affected by equipment surface type and cleanliness. Food Control. 85:177-185.
