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An Integrated Approach to Promoting the Production, Safe Handling, and Marketing of Speciality Leafy Green Vegetables in Colorado


The first objective will be to develop a comprehensive list of available seed sources for specialty leafy green vegetables, herbs, and salad mixes that have potential for sustained production and direct marketing in Colorado. Managers of international and natural grocery markets, locally-owned restaurants (traditional, Asian, Hispanic, and Thai), and farmers markets will be interviewed to assess local market demand of various specialty leafy green vegetables, herbs, and mixed salads. Growth trials will be conducted on a diverse selection of leafy green vegetables, herbs, and salad mixes, utilizing standard greenhouse growing methods. Because of the possible consumer appeal of organic production, the potential food safety benefits of hydroponic production, and the economical season-extension capabilities of high tunnel production, these three methods will be tested on a limited number of leafy green species. The choice of production method will be based on specific crop characteristics and previous production knowledge. Production data including yield, length of growing time, and labor inputs will be documented. Production costs and characteristics, sensory properties, total phenolic content, antioxidant capacity, and effects of shelf life and processing methods on quality and microbial properties of top selected leafy green vegetables, herbs, and salad mix combinations will be evaluated based on results of trials (Objective 2). The effects of pre-washing on shelf-life and general microbial levels will be compared to unwashed leafy greens. A search of nutrient databases and scientific publications will be conducted on selected greens to compile available nutritional information. A leafy green vegetable production safety checklist will be developed that can be utilized by growers and buyers to validate adherence to Good Agricultural Practices (GAPs). Fair market value and marketing strategies for specialty greens will be established. Selected choices of leafy greens, herbs, and salad mixes will be tested with the CSU student-run restaurant, Aspen Grille, the local food service facility, Spoons, and the CSU Community Supported Agriculture (CSA) organization, using interviews with restaurant personnel and questionnaires with CSA members to gather feedback. Graduate and undergraduate horticulture students will be engaged in growing, harvesting, and conducting market transactions. Outreach information will be disseminated with the intention to increase knowledge about production of specialty greens and promote safe food handling methods used by producers and retail users. Web-accessible and printed fact sheets will be developed that incorporate high quality images with information pertaining to food safety, nutritional properties, production characteristics, culinary uses, and available seed sources for alternative and commonly consumed leafy greens. Formative and impact evaluations of the fact sheets will be conducted.

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NON-TECHNICAL SUMMARY: Available choices of locally grown leafy green vegetables are generally limited and adherence to safe produce handling methods are often not verified. The potential exists to increase local production of fresh specialty leafy green vegetables, herbs, and salad mixes that could be marketed to restaurants and retail grocers and to consumers through local farmers' markets. The identification and production of leafy greens well-suited to Colorado will be expanded and the safety of handling methods improved and documented. <P>APPROACH: Organic production methods will conform to those requirements set by USDA for organic certification. Samples will be collected in triplicate, triple rinsed with tap water to remove growing medium and blotted dry with paper towels. Each sample will be weighed, freeze-dried and stored at -30 degrees C. Freeze-dried tissue will be finely ground with a coffee mill and sieved through a 20 mesh screen. Four hundred mg. of ground tissue will be extracted in 10 mL of 80% acetone, vortexed for 30 seconds, and rotated in the dark for 2 hours. After centrifugation at 3800 rpms at 4 degrees C for 15 minutes, 1 ml aliquots will be transferred to four 1.5 ml Eppendorf tubes. Acetone will be vacuum centrifuged at 45 degrees C for approximately 3 hours. The extracted samples will be kept at -30 degrees C until further analysis. The Folin-Ciocalteu assay will be used to determine the quantity of total phenolic compounds following a microplate adaptation of the spectrophotometric method of Singleton and Rossi and Spanos and Wrolstad. Absorbance of the chromophore at 765nm will be used to estimate total phenolic content by derivation from a standard curve based upon gallic acid and expressed as milligrams per g of tissue weight. The presence of ascorbic acid in vegetable extracts can interfere with the Folin-Ciocalteu assay but data can be adjusted for this interference if necessary. An ABTS antioxidant assay based on the capacity of a vegetable extract to reduce the ABTS radical will be used to estimate radical scavenging capacity. Results will be expressed as trolox equivalent antioxidant capacity, TEAC. To assess possible differences in characteristics such as flavor, appearance, texture, aroma, and overall acceptability, a consumer panel (n = 20) will evaluate salad mixes, leafy vegetables, and herbs. Guidelines of the Human Research Committee at CSU will be followed in all stages of sensory analysis. Panelists will be recruited from university students, faculty and staff members. The leafy greens will be processed and prepared for tasting by consumer panelists mid-morning following harvesting. Greens will be presented raw or cooked according to the traditional method used for that type of leafy green, i. e. collard greens would be cooked, salad mixes would be served raw. The organoleptic attributes will be scored using 9-categorical hedonic scales ranging from unacceptable to very acceptable. To monitor the microbiological quality of samples of leafy greens, total aerobic bacteria and coliform populations will be enumerated at three time intervals using standard plate counts (SPC) and total coliform (TC) assays using methods outlined in the FDA Bacteriological Analytical Manual. Samples will also be tested at three time intervals for texture differences with a TA-XST2 Texture Analyzer and color using a HunterLab ColorFlex spectrocolorimeter. Visual, color, and texture characteristics will be used to determine maximum shelf life at recommended refrigerator temperatures. <P>
PROGRESS: 2007/07 TO 2007/12<br>
Leafy green vegetables are frequently underutilized despite their well-known health benefits. There is increased interest among consumers and retailers in purchasing locally grown produce but a number of barriers can impact the availability of locally grown specialty vegetables. One of the primary aims of this research project was to assess the local demand for specialty leafy green vegetables by conducting a series of interviews with managers of local restaurants, international grocery stores, and farmers markets. In the fall of 2007, fourteen managers of international grocery markets (2), locally-owned Thai, Indian, Asian and traditional restaurants (9), and Larimer County farmers markets (3) were interviewed to determine factors that influence the use of various leafy green vegetables, herbs, and mixed salads (Lapakulchai, 2007). Retail managers listed lack of knowledge about local sources and lack of familiarity with health department regulations as primary barriers to purchasing locally grown produce. It appears that the promotion of locally grown foods needs a catalyst for establishing a collaborative network between local producers and retail businesses. The potential exists to increase local production of specialty greens and information from these interviews will be used in the development of recommendations for local producers interested in supplying produce for this market.
IMPACT: 2007/07 TO 2007/12<BR>
Information gathered during these interviews, along with input from university personnel, was used to develop a comprehensive list of leafy green crops that would have potential for demand in the local market. Seed sources were located and 67 different cultivars have been obtained for growing trials. Fifty-four cultivars are currently being grown, both hydroponically and conventionally, in randomized screening trials at a greenhouse to determine production characteristics. In addition to the interview information, a local survey of farmers market customers (n = 100) was conducted in September (Yeh, 2007). Questions in the survey were specifically targeted at determining consumer habits related to handling leafy greens and consumer attitudes toward locally grown produce. Forty-two per cent of consumers surveyed listed support of local business as their primary reason for shopping at Fort Collins farmers markets (compared to 25 per cent from a similar survey in 2001) and 58 per cent stated that purchasing locally grown produce was more important to them than buying organically grown produce. Seventy-one per cent of respondents reported washing salad mix purchased at farmers markets prior to consumption. Results from this research project can contribute to the base of scientific knowledge related to vegetable production as well as benefit consumers, the local economy, the community, and the environment. Consumption of a diverse selection of leafy green vegetables can promote improvements in consumer health and maximum nutritional content is generally associated with freshly harvested produce. Colorado's climate is well suited for cool season crops, like leafy greens. The state is currently third in U.S. production of lettuce and fifth in spinach and has the potential to become a leader in specialty greens production. The popularity of farmers' markets and community supported agriculture programs are increasing and provide economic benefits for local producers and social benefits for participants. The reduction in food miles that results from local production can have a positive impact on the environment and reduce energy input.

Bunning, Marisa
Colorado State University
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