Thesis (M.S.)--University of Hawaii at Manoa, 2007. / Includes bibliographical references (leaves 61-66). / vii, 66 leaves, bound ill. 29 cm

Thesis (M.Sc.(Agric.)) -- University of Pretoria, 2008. / Abstract in English. Includes bibliographical references.

Thesis (M.S.)--University of Tennessee, Knoxville, 2004. / Title from title page screen (viewed Oct. 04, 2004). Thesis advisor: F. Neal Schrick. Document formatted into pages (xiii,105 p. : ill.). Vita. Includes bibliographical references (p. 86-104).

Thesis (Ph. D.)--University of California, San Diego, 1999. / Vita. Includes bibliographical references (leaves 252-261).

Thesis (Ph. D.)--University of California, San Diego, 1999. / Vita. Includes bibliographical references (leaves 252-261).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1963. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.) - University of Queensland, 2006. / Includes bibliography.

Thesis (B.App.Sc. (Hons.)) - University of Queensland, / Includes bibliography.

Due to the complexity and dynamism of the global beef market, policymakers need a theoretically consistent, rigorous and quantitative analysis to validate and quantify the effects of different factors that are believed to drive beef trade. The general objective of this dissertation was to validate and quantify the factors that drive and influence international beef trade in order to facilitate and improve the decision-making behaviour of policymakers. The gravity model methodology was identified as the ideal framework to address the general objective of this dissertation, and was used as the primary tool to analyse the factors that drive and influence beef trade. The specific objectives were to gain an understanding of prominent issues that influence international beef trade, to review the gravity modelling methodology and to model the effects of various issues on the volume of beef trade based on trade data among leading importers and exporters between 1996 and 2010. A model was estimated using two separate equations, referred to as Model B1 and Model B2. For each of these equations the dependant variable varied to represent: bovine cuts boneless, fresh or chilled (HS 020130); bovine cuts boneless, frozen (HS 020230); and an aggregation of these two products designated as "Total beef". Model B1 was estimated with the full gravity model specification, including export prices. Since very few studies on commodity specific gravity models exist and have never modelled beef exports prices directly, it was decided to run an additional model, Model B2, without the export price variable. The Wald Chi-square test confirmed that the variables included in the model were significant in explaining the variation in the volume of exports. Issues that were included in the specification included beef production in a beef exporter, beef consumption in a beef importer, tariff measures applied by importing countries, income per capita of consumers in importing countries, export prices and trade bans due to animal diseases. The coefficients of individual variables estimated were found to be plausible while the signs of the coefficients indicated the expected relationships between the volume of beef trade and each of the individual issues. After comparing the two models it was found that the price variable exhibited statistically significant and plausible results, and did not affect the estimates of the other variables. A comparison with similar studies revealed that the model developed in this dissertation estimated similar results in some areas, and even more plausible results in others. When all of the statistical tests and validation criteria are taken into account, the gravity model developed in this dissertation was successful in validating and quantifying the factors that drive and influence international beef trade. / Dissertation (MCom)--University of Pretoria, 2014. / gm2014 / Agricultural Economics, Extension and Rural Development / unrestricted

Contamination of meat with microorganisms during slaughter is inevitable. Hygiene management systems (HMSs) such as the Hygiene Assessment System (HAS) and Hazard Analysis Critical Control Point (HACCP) are used to prevent the contamination of beef with both spoilage and pathogenic microorganisms during slaughter. This study compared the effect of the HAS alone and a combination of HAS + HACCP on the microbiological quality of beef and investigated the survival of Escherichia coli O157:H7 co-cultured with different levels of Pseudomonas fluorescens and Lactobacillus plantarum on fresh beef. HAS alone and HAS combined with HACCP systems were each represented by two abattoirs. Sponge swab samples were collected from chilled beef carcasses for indicator organisms: Aerobic Plate Counts (APC), Enterobacteriaceae, Pseudomonas spp., and lactic acid bacteria. Swabs were also collected for pathogenic bacteria: E. coli O157:H7, Staphylococcus aureus and Salmonella spp. There was no significant difference between the microbiological quality of beef carcasses processed in the abattoirs with the HAS and that of beef carcasses processed in abattoirs with combined HAS + HACCP. E. coli O157:H7 was isolated from carcasses processed in an abattoir with the combined HAS + HACCP system. Moreover, although overall S. aureus counts at all abattoirs were comparable, a higher incidence (47% of carcasses) was obtained from an abattoir with combined HAS + HACCP. Salmonella spp. was not detected during the study. The microbiological quality of beef at HAS abattoirs is not significantly different to that of beef processed at HAS + HACCP abattoirs. The combined HAS + HACCP did not prevent contamination of beef carcasses with E. coli O157:H7 and S. aureus. Effective implementation of HAS can reduce contamination of beef with spoilage and pathogenic microorganisms. The effect of different levels of P. fluorescens (102 and 106 log10 cfu/ml) and L. plantarum (102 and 104 log10 cfu/ml) on the survival of E. coli O157:H7 on beef loins was investigated. Sterile beef loins inoculated with E. coli O157:H7 and P. fluorescens were aerobically stored for 7 days at 4°C, while those inoculated with E. coli O157:H7 and L. plantarum were vacuum-packaged and stored for 8 weeks at 4°C. APC, E. coli O157:H7 and either P. fluorescens or L. plantarum counts were determined at different storage intervals. For the aerobically packaged beef loins, E. coli O157:H7 was detected throughout the 7-day storage period regardless of the P. fluorescens level in the inoculum. For the vacuum packaged beef loins, similar inoculum levels of E. coli O157:H7 and L. plantarum allowed E. coli O157:H7 to survive until week 5 of storage, while a higher inoculum level of L. plantarum inhibited E. coli O157:H7 from week 3. Once fresh beef has been contaminated with E. coli O157:H7 the level of P. fluorescens in the background flora does not inhibit its survival and growth. However, under vacuum storage, the application of L. plantarum as a biopreservative inhibits the survival of E. coli O157:H7 on beef. Comprehensive strengthening of preventive strategies is required to eliminate contamination of beef carcasses with E. coli O157:H7. Bacterial contamination of carcasses during slaughter is inevitable. Effective implementation of HAS at abattoirs produces beef carcasses of microbiological quality comparable to that produced through the use of combined HAS and HACCP. While the level of P. fluorescens on beef does not inhibit the survival of E. coli O157:H7 on aerobically stored beef, the combination of L. plantarum, and low storage temperature inhibits the survival of this pathogen on beef under vacuum storage. / Thesis (PhD)--University of Pretoria, 2011. / Food Science / unrestricted