Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Oct. 10, 2007). PDF text: xv, 325 p. : ill. UMI publication number: AAT 3258775. Includes bibliographical references. Also available in microfilm and microfiche formats.

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Raw product value of vegetables for processing in the Northwest used to be established by a competitive market involving proprietary processors and growers. Due to the relocation of proprietary processors to the Midwest, this competitive market has eroded forcing cooperative processors to seek other means to set raw product values. In the absence of a competitive market for raw product, cooperatives must rely on an average of last year's prices paid by processors in a given region to value raw product. This method of lagged averages may be resulting in misallocated contracted acreage to grower-members of cooperatives, and inappropriate production levels of the processed good given market conditions. Therefore, the principal objective of this research is to develop and evaluate alternative methods of forecasting raw product value. Since the market for processed vegetables at the retail level is competitive, one alternative method employed was to use a forecast of supply and determinants of demand affecting retail price to forecast raw product value. These explanatory variables were regressed against raw product values of various crops obtained from a northwest processing and marketing cooperative. The raw product values were expressed as net returns/acre to the crops under investigation. The estimated equations, which had adjusted R²'s ranging from .267 to .851, were used to forecast raw product value. A second forecasting method investigated in this study was an exponential smoothing model. Raw product value forecasts were generated over two different time horizons, identified by the cooperatives' accounting procedures. The two alternative forecasting methods were compared to each other, and to the method currently in use by the cooperative, with the aim of determining the most accurate forecasting technique. Results showed that both the econometric and smoothing approaches fit the data better over the estimation period than did a naive lagged price estimate resembling the present method in use by the cooperative. The econometric method also fit the data better than did the smoothing approach. The econometric model provided poor forecasts for the longer forecast horizon, but proved to be effective in the shorter. The smoothing technique forecasted more effectively in the longer forecast horizon as compared with the shorter. These results suggest the importance of the forecast horizon in determining the more appropriate forecasting technique. Both forecasting techniques proposed in this study produced forecasts which were more accurate than the cooperative's present method at least half of the time. This suggests that viable alternatives to the present method of establishing raw product value exist for agricultural cooperatives. / Graduation date: 1986

This investigation was concerned with the reduction of waste in raw vegetables and fruits between the times of harvest and consumption. Reduction of spoilage in produce was attempted by means of chemical and. physical agents as well as a combination of both. The first phase of the work consisted of an evaluation of a number of chemical compounds with respect to their effectiveness in reducing post-harvest spoilage. The second part dealt with an evaluation of several transparent films applied to raw produce as wrappers and their effect on the keeping quality of the plant material until consumed. Finally combinations of surface disinfection and overwrapping were evaluated for effectiveness against raw produce spoilage. 1. Disinfection Approximately 26 compounds were tested as aqueous dips using 3 concentrations of each on 7 major vegetables and 2 fruits. The following types of compounds were studied. 1. Quaternary ammonium compounds (chlorides, bromides and pyridinium derivatives) 2. Chlorine liberators (organic and inorganic) 3. Phenols (simple and poly-phenols) 4. Quinones and hydroquinones 5. Salts of fatty acids 6. SO₂ liberators 7. Benzoates The chemical treatments were evaluated for each produce by comparison with untreated controls using duplicate tests with triplicate samples for each chemical and concentration. Promising treatments were found for all but one produce (strawberries). The treatments showing promise for each of Pascal celery and Emperor grapes were further tested on a larger scale uaing commercial size units of produce as test samples and long term cold storage. Three chemical treatments for each product were judged satisfactory enough to warrant further testing by means of field trials. The chemicals found most promising for celery were Onyxide, Cetab and Decco while Roccal, Dowicide C and Phygon were selected for grapes. A field test of the three above mentioned treatments for Pascal celery was completed. One thousand bunches per chemical were tested under commercial conditions of dipping and storing. An equal number of untreated bunches was also tested. Half-lots of each treatment were evaluated on each bunch for 11 subjective characteristics and standard mold and bacterial counts of each crate of celery were made after 8 and 14 weeks of storage. On the basis of a statistical analysis of the results, 0.1% Decco of pH=5 can be recommended for the reduction of general rot development in cold storage Pascal celery. Onyxide and Cetab significantly reduce the development of mold but commercial application cannot be recommended because the amount of visible stalk injury was significantly increased over that shown by corresponding untreated or Decco treated celery. 2. Prepackaging The following films were compared for their merit in prolonging the salable life of raw produce. Pliofilm 75FF, Pliofilm 75N2, Pliofilm 75P6A, Cellophane 300LSAT, Cellophane 300MSAT-86, Lumarith P-912, Dupont Acetate 100CA48, Polythene and Kodapak II-130. Wrapping techniques were also evaluated using the followng variations; Complete seals, tent-flap closures, single hole punctures, multiple punctures and windo bags. The following products were studied: celery, tomatoes, carrots, lettuce, cauliflower, chopped salad mix, spinach, strawberries, raspberries, blackberries, and boysenberries. Harvested produce was packaged both before and after the removal of field heat. Behavior of the pre-packaged products in both 33°F storage and subsequent 8O°F storage was studied. Cold storage was extended as long as 120 days while subsequent holding at room temperature varied widely from produce to produce. Observations were made at regular intervals for each product. Several hundred uniform samples were evaluated for most products using duplicates of each treatment for every observation period. Evaluation of most samples included weightloss, C0₂ (and sometimes O₂) of the container atmosphere, mold and decay development, flavor, color, odor, wilting and shriveling. The following conclusions were drawn: All films and wrapping methods affect produce quality. For each produce, treatments could be singled out which were superior to unwrapped controls. However any particular film and type of seal found to be superior for one produce was often not acceptable for another fruit or vegetable. Among the factors found to be critical for the proper choice of treatment were type of produce, produce temperature when packed, length of storage, and temperature of storage. A. Cold Storage For most products, the partially sealed, low permeability MSAT containers and the completely sealed Polythene wraps scored highst for overall product quality. These treatments prevented the accumulation of undesirable CO₂ while at the same time protecting the produce against weightloss and consequent wilting. For some produce, especially berries, wilting was not apparent even in high permeability films such as acetates. B. Warm Storage For produce with high respiration rates (spinach, and berries) only acetate films were acceptable as wraps. The partially sealed low permeability films maintained good quality in warm storage but the high humidity within the package was conducive to micro-organism activity. Thus, in many cases samples disinfected prior to packaging in those films improved the warm storage quality. Disinfection also improved the quality of tomatoes and chopped salad mix in acetate wraps. Of the high permeability films, no significant difference was found among the Dupont acetate, Lumarith and Kodapak II. The type of seal also did not affect the characteristics of these wraps. The low permeability films differed principally in the amount of CO₂, retained by the container during storage. The Pliofilms retained the highest C0₂, levels followed by LSAT and then MSAT Cellophane. The sealed polyethylene, the single puncture and tent flap MSAT wraps exhibited similarity, especially with respect to C0₂ accumulation. The multiple puncture low permeability wraps showed characteristics between acetates and the last mentioned group. Correlation between CO₂ accumulation and off-flavor formation could be determined for most products. Higher CO₂ levels were tolerated at short storage intervals without off- flavor formation by most products but the rate of change in CO₂ tolerance varied from produce to produce. Correlation between % weightioss and degree of wilting could also be expressed as a function of the pre-packaging treatments used. Storage infection was eliminated by all films independent of the type of seal used. It should be emphasized that only a study of the resuits and relationships discussed under each product can serve as a basis for future work and commercial application of the methods presented in this work. / Graduation date: 1950

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<p align="justify">It is widely recognized that increased participation in international trade and investment can serve as an engine for economic growth and development.<font size="1">1 </font>Implicit in international trade is the principle of comparative advantage that generally provides that states should trade with each other because they are better off by maximizing their production potential for some products and, through trade, obtain products they do not have or produce with less efficiency.<font face="Times New Roman,Times New Roman" size="1">2 </font>Such comparative advantage, <em><font face="Arial,Arial">inter alia</font>, presupposes a well-regulated trading system. Though attempts have been made to regulate the multilateral trading system by the GATT 1947 which was but meant to form only part of an agreement on the stillborn International Trade Organization (ITO), the first rule based World Trade Organization (WTO) was established only in 1995 and a number of countries have acceded to it thence. While there is no consensus on whether developing countries in general and the least developed countries (LDC s)<font size="1">4 </font>in particular are beneficiaries of the system<font face="Times New Roman,Times New Roman" size="1">5</font>, some countries have embarked on the accession process.<font face="Times New Roman,Times New Roman" size="1">6 </font>Ethiopia is one such country.</em></p>

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Master of Agribusiness / Department of Agricultural Economics / Aleksan Shanoyan / The fresh produce retail market is becoming increasingly competitive and the need to cut costs in order to invest in retail prices and innovations is critical. Seasonality of commodities cause market shoulders where retailers face increased prices and an insecure supply base with risk of being out of product. The implications of paying more than competitors or not having a product on the shelf can risk losing a customer’s business to a competitor. This thesis is an analysis of procurement strategies by retailers in the fresh produce industry, in order to maximize efficiency by reducing cost of goods and securing supply. Specifically, this thesis will analyze different procurement strategies for procuring lemons out of the California San Joaquin Valley. The analysis will compare traditional market buys vs a vertically integrated procurement model in which the retailer procures farm land and controls the commodity from farm to store shelf. While the fresh produce industry has had an evolution over the past century, models of procurement are not following other industries in advancements such as innovations from technology, genetics and sustainability. By advancing procurement models the industry has the potential to not only benefit farmers and retailers but also deliver the customer a fresher product at a reduced price. The objective of this project is to investigate the ways to minimize commodity costs for the retailer and gain security of supply by analyzing procurement strategies for procuring lemons from California. This project is intended to support the fresh produce supply chain and specifically the retailer to optimize their procurement model. To determine an optimal strategy this project will compare and contrast traditional market buys vs a vertically integrated strategy. This is to determine if vertically integrating this commodity in a retailer supply chain would result in a net reduction of cost. Also, this project will determine if security of supply is gained through vertical integration vs traditional market buys. This project will consider variables such as market prices, supply/demand, sustainability and other industry implications. The data examined includes retail pricing and costs, farm production and cost, property market values, and other variables and inputs. The methods of analyzing the data include profitability scenarios throughout multiple procurement models for retailers to determine an optimal procurment model. As a result of the data and methods it is determined that there is an opportunity throughout the produce supply chain for retailers to shift away from traditional procurement models. This project’s proposed land acquisition procurement model is an alternative strategy that can supplement traditional procurement model and would potentially reduce cost of goods and improve supply reliability. This vertically integrated procurement model creates supply chain efficiencies and reduces cost for the retailer along with increasing the retailer's security of supply in the fresh produce commodity market. This analysis should serve as a basis and guide for retailers to determine their company’s optimal procurement model.

Many intervention methods theoretically have the potential to eliminate microorganisms. However, they do not perform efficiently once applied to fruits and vegetables. In this study Salmonella Typhimurium LT2 and hydrogen peroxide (H2O2) were used as model systems on 6 different types of produce to determine the effect of produce surface characteristics on sanitizer effectiveness. Microbial attachment on produce surfaces was induced after 3 h of drying at 24°C and high relative humidity (RH). Afterwards, produce was stored for 3 subsequent days and washed with sterilized tap water for 5, 10 and 15 minutes to separate weakly from strongly attached microorganisms from the produce surface. The strongly attached microorganisms were then treated with 3% H2O2 for 1, 3, and 5 minutes. These results were compared to the log reduction curves obtained with a pure liquid culture and 3% H2O2. Additionally, contact angle of water and diiodomethane on each type of surface were measured and used as indicator of wettability, and for calculating surface tension characteristics of the produce surfaces. Then these surface characteristics were related to the bacterial attachment and population reduction values obtained after applying the treatments. In general, the geometric mean equation was the most useful in predicting the surface tension values of produce surface and the polar and non-polar components of produce surface tension. Our results suggest that surface properties, such as roughness and surface tension of fruits and vegetables are important factors limiting decontamination. These surface properties allow the formation of micro-air pockets within the rough surface, thus contributing to create a protective environment for microorganisms and reducing the effectiveness of the chemical aqueous based intervention methods applied. Wettable surfaces (water contact angle < 90°) allowed more bacteria to attach after the washing and H2O2 chemical treatments. Roughness and surface polarity are intrinsic characteristics of produce surfaces which affect wettability and the spreading and penetration of the sanitizer treatment on the produce surface. Rough surface and porosity, considered an extreme case of roughness, enhance a deeper cell internalization and a protective environment for bacteria.

Thesis (M.S.)--University of Delaware, 2009. / Principal faculty advisor: John C. Bernard, Dept. of Food & Resource Economics. Includes bibliographical references.