Thesis--Auburn University, 2008. / Abstract. Includes bibliographic references (p.57-67).

Thesis (Ph. D.)--University of Pretoria, 2001. / "June 2001." Includes bibliographical references (p. 164-181). Adobe Acrobat Reader needed to open files.

Environmental factors and produce practices influence the microbial quality of produce. The objective of this study was to determine the microbial quality of irrigation water used for the production of fresh produce in Arizona and factors, which may influence this water quality such as canal size, location and rainfall. A total of 117 samples were collected from irrigation canals in Yuma County between June 2001 and March 2003 and 263 water samples were collected in Maricopa County between May 2002 and February 2003. Parameters such as temperature, turbidity, conductivity and pH were recorded for all samples. Water samples were analyzed for microbial indicators which included total coliforms, Escherichia colt, Enterococcus , and Clostridium perfringens. Sampling sites were examined for the presence of Giardia spp., Cryptosporidium spp., Noroviruses, Salmonella spp. and Campylobacter spp. Samples collected in Yuma County showed that 4.3% of the samples were positive for Giardia spp., 19.6% were positive for Cryptosporidium spp., 17.4% were positive for Noroviruses, 20.7% were positive for Salmonella spp. and 55.2% were positive for Campylobacter spp. Overall, results from samples collected in Maricopa County showed that 2.3% of the samples were positive for Cryptosporidium spp, 18.2% were positive for Noroviruses, 28.9% were positive for Salmonella spp. and 68.7% were positive for Campylobacter spp. Giardia spp. were not detected in any samples. One-way ANOVA did not demonstrate any significant difference between microbial indicator concentrations in samples collected from Yuma and Maricopa Counties. Overall, E. colt concentrations correlated strongly with Enterococcus (r=0.858) in samples collected from Maricopa County. Rainfall within 7 days prior to sampling correlated strongly with overall averages for each indicator, the strongest correlation was seen with E. colt (r=0.726). Overall, the main canals tended to have lower microbial numbers than the lateral/drain canals. In Maricopa County, the sampling sites located furthest north and furthest south on each of the main canals tended to have the higher microbial numbers. The sampling points located furthest south tended to be ranked higher in terms of microbial loads. There appeared to be no positive correlation between the levels of microbial indicators and enteropathogens in this study.

6 pp. / More and more consumers are choosing to buy locally produced foods. Locally grown foods are, fresher, contain more nutrients if picked at full ripeness, and are considered by many consumers to be better tasting than foods that have endured many miles of transportation. Consuming local produce may help communities by stimulating local economies and protecting the environment. This article outlines the benefits of buying locally grown foods. A recipe that is easy and affordable using some local produce is included. A calendar of seasonal produce in Arizona is included in the Appendix.

This publication is issued by The University of Arizona Agricultural Extension Service and Agricultural Experiment Station in cooperation with the Arizona Crop and Livestock Reporting Service of the United States Department of Agriculture, Agricultural Marketing Service, Crop Reporting Board. / This item was digitized as part of the Million Books Project led by Carnegie Mellon University and supported by grants from the National Science Foundation (NSF). Cornell University coordinated the participation of land-grant and agricultural libraries in providing historical agricultural information for the digitization project; the University of Arizona Libraries, the College of Agriculture and Life Sciences, and the Office of Arid Lands Studies collaborated in the selection and provision of material for the digitization project.

Chlorine is the primary method for disinfection of drinking water in the United States; however, growing concerns about the potential hazards associated with carcinogenic chlorine disinfection by-products have resulted in increased efforts to develop alternative methods of water disinfection. In addition, it is sometimes difficult to maintain an adequate concentration of free chlorine throughout a drinking water distribution system due to intrusion events and the presence of biofilms.Silver and copper are widely used as environmental biocides and as clinical antimicrobial agents. Copper has been extensively used as an algaecide for many years, and is reported to be one of the most toxic metals to heterotrophic bacteria in aquatic environments. In this study, silver and copper, both individually and in combination, were able to significantly reduce the numbers of the bacterial pathogens Salmonella typhimurium, Escherichia coli, Listeria monocytogenes, and Mycobacterium fortuitum in aqueous solutions. Silver and copper together could potentially be used as a secondary disinfectant in water treatment because their residual effect is long lasting and no harmful byproducts are generated.Besides water, produce can also be a source of microbial pathogens. Fruits and vegetables are the third leading source in microbial foodborne outbreaks, accounting for more than 10,000 cases of foodborne illness in the U.S. between 1990 and 2001. Alternative produce sanitizers in addition to chlorine were evaluated against foodborne pathogens inoculated onto lettuce. Overall, Fit® (citric acid, grapefruit oil extract) and chlorine yielded the greatest reductions of the study organisms.A large number of compounds are available for use as disinfectants; however, some are highly toxic, corrosive and produce harmful by-products. Natural antimicrobial products are another possible alternative. The efficacy of a natural peptide-based antimicrobial, Absolute Fx, was assessed against bacteria and viruses. Absolute Fx effectively inactivated the study organisms.

The first study was designed to determine the occurrence of bacteria in dishcloths used in restaurants and bars. Coliforms were isolated from 89% of dishcloths and 70% of tabletops. Escherichia coli was isolated from 54% of dishcloths and 20% of tabletops. The numbers of heterotrophic bacteria (HPC) and coliforms were higher in bars than in restaurants. The levels of HPC found in dishcloths were 25-fold and coliforms were 60-to 120-fold lower than the levels found in dishcloths in previous home studies. The most commonly isolated genera from dishcloths in restaurants and bars differed from those in homes. The numbers of HPC on restaurant tabletops were 45-fold greater after cleaning than prior to cleaning. The mandatory use of sanitizers in restaurants and bars may therefore have reduced contamination levels and caused a shift in the microbial populations present in food service establishments. The second study was designed to determine the recovery efficiency and the survival of two respiratory viruses on produce and was compared to the survival of the enteric poliovirus 1. Adenovirus was recovered with an efficiency of 56%, 32% and 35% from lettuce, strawberries and raspberries, respectively. Coronavirus was recovered from lettuce with an efficiency of 19.6%, but could not be recovered from strawberries. Poliovirus was recovered from lettuce with an efficiency of 76.6% and 0.06% from strawberries. The survival of the viruses was observed for up to eight days. Adenovirus survived the longest on raspberries, with a log₁₀ reduction of 0.61, followed by 1.68- and 1.75-log₁₀ reductions on strawberries and lettuce, respectively. Coronavirus declined by 0.41-log₁₀ after two days and >1.34 log₁₀ by day 4 on lettuce. The enteric poliovirus 1 survived longer on produce, decreasing by only 0.37-log₁₀ on lettuce and 1.30-log₁₀ on strawberries. A microbial risk assessment was performed to assess the risk of infection from ingesting 1, 10, and 100 particles of adenovirus on lettuce. The estimated risk of infection by ingesting these numbers were 1:2000, 1:200, and 1:20, respectively and increased in a proportional way as the number of servings was increased from one to ten and 365 servings of lettuce.

The principal objectives of this study are to identify the production factors that influence cocoa productivity at the smallholder's level and to examine resource allocation and technical efficiency in cocoa production. Cross-sectional data collected from 260 cocoa smallholders were used for the study. Both the average production function estimated by the Ordinary Least Squares techniques and the frontier production function estimated by the Linear Programming methodology were employed in the analysis. The results indicated that the input factors which had a significant impact on the production of cocoa were land size, labour, living capital, farm implements and fertilisers. Among the management proxies, only farmer's age, extension contact, farmer's education and the practice of keeping farm records and accounts were important. The data presented in this study 1end support to the hypothesis that the cocoa smallholders were highly inefficient allocatively. Inputs comprising land, fertilisers, and farm implements were underused while labour and living capital were overused. Technical inefficiencies were also present in the study area. The study revealed that a large proportion of the farmers have output levels below their potential. Output could be increased between 18 to 52 per cent if all the least efficient farmers attained those levels of technical efficiency that were achieved by the best farmers in the sample. The variations in technical efficiency in this area were explained by differences in land size, farmer's educational level, their age and the practice of keeping farm records and accounts. This study emphasises the need that increasing efforts must be directed at the least efficient farmers through better and effective management practices and better organization of farm activity without major new investments, at least in the short-run.

No description available.

Typescript. / Photocopy. [S.l. : s.n., 1969?]. 29 cm. / Thesis (Ph. D.)--University of Hawaii, 1969. / Bibliography: leaves 176-179. / ix, 179 leaves