Theses and dissertations (Applied Sciences)

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A study to identify a feasible route for the production of the monomer 2-vinylfuran from furan by evaluating the effect of variables on the final yield and to recommend suitable conditions applicable to the chemical industry
(1992) Gengan, Robert Moonsamy; Reimann, R. H.
2- Vinylfuran has been synthesised from furan, obtained from furfural a degradation product of bagasse, and has the potential to be used as a monomer in the Polymer Industry. Furan was successfully reacted with ethylene under catalytic conditions of palladium (II) acetate and copper (II) acetate to produce 2-vinylfuran, via a direct substitution reaction, at atmospheric pressure and a temperature of 9Y C for two hours in dimethylformamide.
A food qualification at Technikon Natal : influential factors : an attitudinal survey of standard nine pupils' perception of the status of studying at Technikon Natal for a diploma in the food field
(1992) James, Irene Hildegarde; Heath, M. Raymond; Puth, Gustav
To date, the hospitality industry, and in particular the food service industry, has a notoriously high turnover of staff, as well as a general shortage of qualified personnel. This factor, as well as the announcement in 1989 by the South African Government to privatise certain of its catering services over a period of three years caused the authorities to express concern over the lack of trained food staff for the future. Believing that technikons have the infrastructure to qualify culinarians, but that distorted images, prejudices and misconceptions surround technikon education as well as a cUlinary career, this study was undertaken to identify the factors that influence school leavers' choices of study institutions and attitudes towards studying for a food career at Technikon Natal. A theoretical substructure lays the foundation for the study. The literature review in chapter two outlines the historical development of technikons, as well as culinary careers in South Africa, placing special emphasis on the status and image of technikons and food careers. The methodology in chapter three explains the structuring and administration of the questionnaire used to capture data from six randomly selected high schools in the greater Durban area. The processed data results are discussed in chapter four. Table are presented at the conclusion of each group of major issues. These issues include pupils' anticipated study plans, choices of careers and study institutions, and the influence that individuals and other sources may have had on the formation of their attitudes and resultant choices of careers and study institutions. The pupils' attitudes towards studying for a career in the food service industry is thereafter reported on in detail. The results indicated that parents have the greatest influence on career and institution choice although it was found that they provide relatively little information on educational institutions. On the other hand, school teacher-counsellors are found to provide the most information on educational institutions but have far less influence regarding the choice of the educational institution than parents do. Technikon Natal and careers in food are generally positively perceived, but ignorance concerning the academic nature of the Technikon as well as the food diplomas is still evident and needs to be addressed. The study revealed information that could be used to combat ignorance and misconceptions thereby increasing the quantity of applications and subsequent quality of students for both Technikon Natal and the food service industry.
Development of objectives for an educational programme to improve consumer knowledge of and attitudes towards nutritional information on food labels
(1994) Anderson, Diana Jane; Coertze, Dirk J.
Much attention has been given to the prevalence of diseases related to over-consumption of food, with nutritional labelling playing an increasingly prominent role in the prevention and reduction of these diseases. The development of technology and the subsequent availability of processed food have greatly contributed to these diseases, and created gaps in both distance and concept between the consumer and the manufacturer. An increasing number of food manufacturers are providing nutritional information regarding their products in order to maintain their position in the market; however, this avalanche of information is outstripping the ability of the consumer to use it effectively or to even comprehend it. This study was undertaken to identify the objectives needed for the formulation of an educational programme concerning the nutritional labelling of food containers.
Medical laboratory technology in the Republic of South Africa : beyond 2000
(1994) Winchester, Carolyn Margaret; Heath, M. Raymond; Loubser, C. P.
The arena with the for medical technologists result that educational is continually changing directive must change accordingly. A number of big issues have changed the role of the medical technologist. Cognisance of the identified issues is essential if the profession is to survive the year 2000. The future directions of medical technology ar~ analysed in this disseration in order to identify the knowledge and skills that the professional medical technologist will require for the 21st century. The factors which have up to now introduced dramatic changes in clinical pathology laboratories will also present certain opoortunities for laboratory professionals but taking cognisance of the necessity for change and professional ability. This study was thus conducted to explore the educational requirements necessary for the professional future of medical Africa. laboratory technologists in the Republic of South !'.C.,' . A t~eoretical sub-structure lays the foundation for the study. The literature review in Chapter 2 outlines medical technology eduction both in the Republic of South Africa and in certain other countries. The necessity for change in the education of medical laboratory technologists is addressed here. Chapter 3 examines the factors (gleaned from the literature) which are producing a need for such dramatic change for the century ahead. It also examines the role of the technikons and the roles of the technikons with regard to the training of medical technologists and the influence of academic drift. The methodology in Chapter 4 explains the structuring and administration of a questionnaire used to capture data from registered medical laboratory technologists in the Republic of South Africa. The processed data results are discussed in Chapter 5. Tables are presented at the conclusion of certain groups of major issues. Chapter 6 concludes with the findings
The development of a method for the analysis of Mahewu
(1994) de Goede, Richard Goodwin; Adamson, J. H.; Neethling, D. N.
A comparison was made of various methods for the analysis of the odoriferous components of Mahewu, a fermented mealie meal porridge. The most satisfactory procedure was found to be that of dynamic headspace sampling. This technique, used in conjunction with gas chromatography and mass spectrometry, allowed the positive identification of several components .
Criteria based academic and vocational predictor elements for student selection in the National Diploma of Food Service Management programme
(1996) Koen, Pauline Anne; Coertze, Dirk J.
As tertiary institutions, technikons are in the fortunate position that there is a demand for their educational programmes among prospective students, and an equally positive demand for technikon diplomates from the relevant industries who require skilled manpower. Unfortunately resources are limited and thus technikons cannot admit all the applicants who apply for the various courses. For this reason it has become essential to select only those candidates who are most likely to complete the educational training programmes, and fit successfully into the job market. When the value and nature of technikon education are compared to those of a university education, it seems appropriate that their respective students should possess different qualities and abilities, which should be accommodated in the selection criteria governing enrolment.
Evaluation of anaerobic sludges as metal biosorbents and development of a biotechnological process for metal ion removal from selected wastewater
(1997) Bux, Faizal; Kasan, Hamanth C.
As a result of rapid expansion of the industrial sector and increasing population, the environment has been under phenomenal stress. The volume of sewage and other effluents has increased tremendously in the last century. Globally, approximately .12 million tonnes of dry sludge biomass is produced and discarded of by landspreading, landfilling, incineration or dumping in lagoons and oceans. The discharge of industrial effluents into receiving waters has been documented to be the cause of severe environmental contamination. Heavy metals have been the cause of particular environmental concern. Their toxic and carcinogenic potentials at low concentrations, as well as the large quantities disposed to the environment, have prioritised them as leading contaminants. Current technologies of remediating heavy metal containing effluents are expensive and, in most cases, ineffective. Locally, most industries are merely diluting their effluents, thus resulting in the loss of valuable water resources. Waste sludges have shown the ability to adsorb heavy metals from their aqueous environment. Therefore, the current study attempted firstly, to compare biosorptive capacities of various waste sludges for a range of heavy metal ions, and secondly, to establish a relationship, if any, between biosorptive capacity and sludge surface charge. Finally, a laboratory scale biosorption process, encompassing desorption and recovery of metal ions from sludge surfaces, would have to be developed. Effluents used included pure, metal solutions of divalent zinc, cadmium, copper, nickel, trivalent and hexavalent chromium. In addition, synthetic effluents comprising a cocktail of the above-mentioned metal ions as well as an industrial effluent from a metal plating company were used. Five waste digested sludges were prepared and challenged against pure metal solutions to determine and compare their respective biosorptive capacities. Mechanisms of biosorption were elucidated using the Langmuir adsorption isotherm model. Sludge surface charge was determined using the millivolt quantification method. Upscaling of bioreactor trials to fully mixed laboratory scale was also investigated. These experiments encompassed the use of three sludges showing the greatest potential for biosorption and desorption using the selected mineral acid, H2S04, In addition, a simultaneous fully mixed biosorption and desorption process was designed and optimised. Subsequent trials involved comparing the latter process with a packed bed configuration whereby biomass was immobilised using poly sulfone resin. The overall comparative adsorptive capacities of the sludges (SI-SS) for metal ions in single solutions was S3 > S2 > S4 > SS > SI. Surface charge determination showed S3 to contain the most electronegative charge, with other sludges following in the same descending order as mentioned above. These findings supported the theory of a direct correlation between sludge surface charge and biosorptive potential. The affinity series of the sludges for metal ions followed the descending order of Cd2+ > Cu2+ > Ni2+ > Zn2+ > Cr6+ > Cr3+. Fully mixed studies, using mixed synthetic effluents, resulted in lower biosorptive capacities being recorded by the three selected sludges ie., S2, S3 and S4, as compared to single solution experiments. Biosorption studies with industrial effluent, containing Zn2+ as the most prevalent metal at 119.4 mg.F'. resulted in S3 biosorbing a maximum of 4.5 mg.g' of the cation. Sulphuric acid (H2S04) at O.2N, hydrochloric acid (HCI) at O.2N and acetic acid (CH3COOH) at O.4N were tested for their desorptive efficiencies. Sulphuric acid proved to be the most effective desorbing agent. Using S3 as biosorbent and O.2N H2S04 as desorbent, the manipulation and operation of a simultaneous process proved to be successful since both biosorption and desorption occurred concurrently, thus reducing time required for successful remediation considerably. Immobilised biomass, in a packed bed configuration, produced acceptable final effluent regarding standards as stipulated by the Durban Municipality for trade effluents. However, biosorption capacity of the sludge was compromised, with subsequent reductions in desorption being recorded, when the process was compared to fully mixed trials. Affinity series determined for the packed bed process wasC~+ >Cd2+>Zn2+>Cu2+>Cr6+ >Ni2+. Waste digested sludge has shown potential as metal biosorbent on an industrial scale. The present findings have succeeded in demonstrating a novel laboratory scale biotechnological process for the remediation of metal laden industrial effluents.
Quality assessment of frying oils in the formal and informal food preparation sectors
(1998) Mewa, Choonilall; Starkey, Anthony Roland
The demand for fried foods by the public and the number of people entering the fried food industry in the form of take-aways and fast food outlets both in the formal and informal sectors has increased tremendously. Frying fats and oils are very expensive, used in large quantities and is the most important ingredient used in the preparation of fried foods: Due to the high cost of these frying fats and oils, majority of the formal and informal traders are using the frying fats and oils to its maximum in order to reduce the overall cost. This has resulted in the preparation of poor quality offried foods. Considering all of the above, the aim of the proposed research was :- (a) to determine the quality of the frying fats and oils used by both the formal and informal sectors by performing both physical and chemical analyses and compare these with similar analyses performed on the unused frying fats and oils in order to ascertain the degree of deterioration of the used frying fats and oils (b) to investigate the method of disposal of the used frying fats and oils. (c) to contribute in educating both the consumers and the suppliers of fried foods by bringing the findings of this research to the attention of the Durban Metro Health Department. The used frying fats 'and oils were collected during the frying process by the environment health officer from the Durban Metro Health Department. These samples were placed in a refridgerator to prevent any further deterioration. The used and unused frying fats and oils were analysed for, the Free Fatty Acid and Acid Value contents; the quantitative separation of Monoglycerides, Diglycerides and Triglycerides; the Refractive Index; the Peroxide Values; the concentrations of Polar and Non-polar Compounds; the Viscosity and the identification of the various fatty acid methyl esters present in the samples. The analytical methods used were followed from the American Oil Chemists Society (AOCS) Official Method Handbook. The Free Fatty Acid and Acid Value results showed that twenty-five percent of the samples had a concentration of more than the maximum acceptable limit of 2.5%. It was evident that the types of food fried, the intermittent heating, frying
Extraction, characterisation and metal biosorption of extracellular polysaccharides from activated sludge
(1998) Zondo, Raynold Mduduzi; Swalaha, Feroz Mahomed
Waste activated sludge is a biological adsorbent whose potential to remove metals from solution and effluent has been demonstrated. Extracellular polysaccharides (EPS) as components of activated sludge are thought to contribute to activated sludge metal biosorption. During the present study characterisation and determination of the metal biosorptive capabilities of domestic and industrial extracellular polysaccharides (EPS) revealed similarities both in terms of chemical composition and metal adsorption potential. Extracellular polysaccharides were extracted from activated sludge, obtained from domestic and industrial sludge treatment plants, using chemical techniques which involved sodium hydroxide extraction and solvent precipitation. A purification technique, which involved precipitation of protein with chloroform and removal of nucleic acids was developed. To assess the efficiency of the purification method, the ratio of extracted polysaccharide to the amount of protein present was determined. This provided an indication of the magnitude of EPS extracted in relation to the degree of cellular disruption. The type of activated sludge being treated was shown to be of particular importance. The quantity of EPS present in the original sample was found to be higher in domestic sludge than in industrial sludge. Purified EPS was fractionated in a column of DEAE-Sepharose CL-6B using stepwise pH gradient elution. Molecular weight distribution was conducted on a column of Sepharose CL-4B. Component monosaccharides were identified by paper chromatography. Monomers identified were glucose, fructose, glucuronic acid and galactosamine. Ion-exchange chromatography results demonstrated the presence of a number of different polysaccharide fractions while gel filtration results indicated a wide molecular weight distribution range of EPS from both domestic and industrial activated sludge. This indicated potential for variety in the EPS content of the activated sludge. Metal adsorption studies were conducted to determine the capabilities of EPS to adsorb metals
A study of South African strains of the sugarcane mosaic potyvirus (SCMV) identified by sequence analysis of the 5' region of the coat protein gene
(1999) Goodman, Bernadette; Huckett, Barbara Isobel
Sugarcane mosaic potyvirus (SCMV) IS the causal agent of the most important viral disease of sugarcane in South Africa, mosaic. Accurate knowledge of the prevalent SCMV strain(s) in the South African sugar industry is lacking and has never been determined using molecular analysis. Identification of SCMVstrains at the genomic level would provide valuable information for the development of appropriate in vitro diagnostic tests and in the genetic engineering of sugarcane for coat protein (CP) mediated resistance.
The design and development of software simulating interactive marine radar and electronic navigation instruments based on a PC platform
(1999) Cox, Kieron Michael Tesling; Stewart, M. J. M.
This study was intended to develop suitable software to emulate Marine Radar and other Electronic Navigation Systems found on Merchant,vessels. This equipment includes Radar with or without Automatic Radar Plotting facilities, Navstar Global Positioning Systems, Echo Sounders, Radio Direction Finder as well as Decca Navigator. Certain of these aids are required in the Radar Simulator Specifications [ref 1] to which the SAMSA - South African Maritime Safety Authority (formerly the South African Department of Transport) adheres. SAMSA is the authority which approves Maritime training and Simulators in South Africa in compliance with International standards as laid down by, IMO - International Maritime Organisation.
The role of tissue kallikrein in helicobacter pylori-associated gastric disease
(1999) Naidoo, Strinivasen; Bhoola, K. D.
Today, the number one income-generating drugs are remedies prescribed for gastric disorders, in particular dyspepsia. These clinical conditions have a multi-faceted aetiology and pathology of dysfunction. One likely causal factor is the entero-pathogen Helicobacter pylori. It has been shown to be more than just a commensal related to gastric diseases like dyspepsia (80-90% incidence) and duodenal ulcer sufferers (100% incidence), with a total estimated world-wide population infection of 50%. The current therapy offered to dyspepsia sufferers is a triple regimen of an anti-bacterial, an Ir proton-pump inhibitor, and bismuth colloidal salts.
Cross-linking of saturated long-chain hydrocarbons
(1999) Ishripersadh, Kogilambal; Luyt, A. S.; Timm, Delysia Norelle
Saturated long chain hydrocarbons, such as paraffin waxes, have a large variety of applications. These applications may, however, be restricted by certain properties of the wax such as brittleness and in compounding. Cross-linking of the long chains in waxes may provide improved physical properties and hence a wider application of these waxes
The isolation, identification and characterisation of the causative agent involved in the "paralysis syndrome" and the implementation of suitable control measures
(1999) Govender, Mogambery Kisten; Kasan, Hamanth C.
"Paralysis syndrome" was first described by Dr M.J Versveld in 1993. The disease appeared to be confined to the Natal area with a few sporadic outbreaks in Gauteng, but none in the Cape region, nor in non-Rainbow flocks. The syndrome tended to re-appear on affected farms but not necessarily in the same houses. There was no correlation between affected flocks and their parent flock or hatchery identity (Maharaj, pers.comms.1994).
Identification of polyphosphate accumulating bacteria from pilot- and full scale nutrient removal activated sludges
(1999) Atkinson, Blaise William; Bux, Faizal
General removal of phosphorus (P) from wastewater was introduced in Scandanavia in the late 1960's. At that time it was believed that P alone was limiting to algal growth and that the sole removal of P would solve the problem of eutrophication. However, we now know that both P and nitrogen (N) contribute to this deleterious effect and as such, much research has been conducted concerned with both the biological and chemical removal of these nutrients from sewage effluents. Enhanced biological phosphorus removal (EBPR), which is basically the biological accumulation of soluble P (as polyphosphate or poly-P) from the bulk liquid in excess of normal metabolic requirements, still tends to be sensitive to many external parameters and, as such, is subject to fluctuations. This makes it extremely difficult for wastewater treatment installations to achieve and maintain full compliance with strict discharge regulations. A more comprehensive understanding of the microbial community within the mixed liquor of a wastewater treatment system is therefore required which will ultimately assist in improving system design and performance. Chemical and civil engineers, when designing biological wastewater treatment systems, consider only the processes (biological or chemical) taking place within the reactor/s with little or no regard for the individual microbial species or the entire microbial community involved. Process design appears to be tackled empirically from a 'black box' approach; biological reactions or processes occurring within a system such as wastewater treatment are all lumped together and attributed to a single surrogate organism ie., the response of the surrogate to certain stimuli accounts for the total system response. This is similar to an analogy which Professor George Ekama (Dept of Civil Engineering, UCT), a leading scientist in wastewater treatment and process design, refers to where engineers, if, for example, are confronted with modelling the dynamics of carbon dioxide utilisation ofa forest, would recognise the accumulative system response and not give cognisance to each individual tree's contribution. It is true that if one had to consider every microbial species present in a highly organised community such as activated sludge, process models, designed to make quantitative and qualitative predictions as to the expected effluent quality from a particular design, would become increasingly complex and superfluous. It is evident from the countless accomplishments that engineers have succeeded, to a certain degree, in modelling wastewater treatment systems. One only has to consider the tremendous success of biological P (bio-P) removal and nitrification/denitrification processes at full-scale. However, there are limitations to this empirical approach and EBPR processes occasionally deteriorate in phosphate removal efficiency. In order to further optimise biological processes, whether they be organics oxidation, bio-P removal, nitrification or denitrification, biological community analyses will have to play a more significant role in design. The better microbial community structure and function is understood, the better the control and management of the system. With the advent of improved microbial identification and enumeration (to a certain extent) techniques (in situ), it was considered significant to investigate the mechanism ofbio-P removal and to elucidate which bacteria are actively responsible for this process. To this end, experimental work was conducted in two phases: \xAE laboratory, where samples of mixed liquor were obtained from a full-scale wastewater treatment facility exhibiting biological nutrient removal (BNR) characteristics and @ pilot plant, where an enhanced culture ofpolyphosphate accumulating organisms (PAO's) was developed and probed using molecular identification and enumeration techniques (as well as a cultivation-dependent approach). During phase \xAE of experimentat
An environmental study to examine the distribution of selected airborne metals in the greater Chatsworth area
(1999) Govender, Suendharan; Pillay, Visvanathan Lingamurti
The purpose of this study was to determine the distribution of selected metals in the atmosphere of the greater Chatsworth area. Six primary schools in the area were selected for the investigation. Two high volume air samplers were placed at one ofthe sites from 7hOOto I5hOO on school days. The filter assembly on which air particulates were collected was placed at a height of 1.45 m's above the ground. The vacuum pumps were preset to start and switch off at the selected times. Sampling was done for seven days from February to June and again for seven days from July to November at each of the six sites.
Directed evolution of B-xylanase from Thermomyces lanugtnosus
(2000) Stephens, Dawn Elizabeth; Permaul, Kugen; Prior, A.; Singh, Suren
Most natural enzymes may be unsuitable for biotechnological processes since they have evolved over millions of years to acquire their specific biological functions. Such enzymes are often genetically altered to suit the rigours of industrial processes. Directed evolution is one such strategy and makes use of iterative rounds of random mutagenesis, screening and recombination to enhance the existing properties of enzymes. Thermomyces lanuginosus is a thermophilic fungus that produces high levels of a thermostable xylanase. The xylanase gene from T lanuginosus DSM 5826 (xynA) was functionally expressed in E. coli as a LacZ-fusion protein (Schlacher et al., 1996) and later crystallized (Gruber et al., 1998). In this study, it was undertaken to improve the thermo stability and catalytic activity of xynA using error-prone PCR with different concentrations of MnCh. The first step prior to mutagenesis was to determine the levels of xylanase that could be attained by the wild type XynA, both in the presence and absence of an inducer. IPTG, a lactose analogue, was used since xynA was expressed with a lac promoter. High amounts of IPTG were found to adversely affect xylanase production, whilst a low amount (0.1 mM) enhanced xylanase production. This amount was used to later induce xylanase production by the variants obtained after mutagenesis. IPTG was found to increase the rate and production of xylanase. After random mutagenesis of xynA, transformed colonies were first selected for xylanase production on 0.4% Remazol Brilliant Blue xylan and then screened at different temperatures for improved stability and activity. After the first round of screening, four variants, viz., IB5, IB7, IBLl and ID2, showed slight improvement in both stability and activity and were subjected to further mutagenesis, using low concentrations of MnCh. Three variants, viz., 2B7-1O, 2B7-6 and 2BIl-16, with markedly enhanced stability, were obtained. Variant 2B7-10 exhibited a five fold higher activity (3430 nkat/ug total protein) than the wild type XynA (657 nkatl ug total protein). It retained 71% of its activity after treatment at 80°C for 60 min and had a t1/2of 215 min at 70°C, which is higher than that attained by XynA. Long-term thermo stability screening at 70, 80, 90 and 100°C revealed that variants 2B7-6 and 2B11-16 were, however, the most stable enzymes generated in this study, although their activities were lower or almost comparable with their parents. Sequence analysis of variant ID2 revealed 4 amino acid substitutions within the a-helix of the protein. This region was strongly conserved with the more stable variant xylanases generated in this study. The most profound mutation seen with variant 2B7-10 was the disruption of the disulphide bridge. Most of the mutants obtained in this study displayed a trade-off between stability and activity, the exception being mutant 2B7-10. Currently, DNA shuffling techniques are being used to recombine these traits in a single xylanase.
Concurrent analysis of the mycotoxins, cyclopiazonic acid, moniliformin and ochratoxin A using capillary zone electrophoresis
(2000) Govender, Urishani; Odhav, Bharti
Mycotoxins are a group of natural poisons produced by certain strains of fungal species when they grow under favourable conditions on a wide variety of different substrates. These toxins have been implicated in a wide range of acute diseases in man and animals. Their toxic effects include oesophageal cancer and liver diseases in humans, and carcinogenic effects in experimental rats and poultry. Hence, there is a need to monitor toxin levels in food commodities.
The isolation and characterization of phytoalexin and constitutive agents from plants for mycotoxin control
(2000) Mohanlall, Viresh; Odhav, Bharti
Plant medicine is an important area of commercial activity in South Africa. This is a rapidly expanding market, thus we are evaluating natural and stressinduced compounds (phytoalexins) from plants as agents that may be able to control mycotoxins. Natural compounds from Bridelia micrantha, Warburgia salutaris, Lippia javanica and Scenecio serratuloides and stress-induced compounds (phytoalexins) from Citrus sinensis cv Valencia were screened for antitunqal and antimycotoxic activity by bioautography against a test organism (Cladosporium cladosporoides) and mycotoxin producing fungi (Fusarium moniliforme and Aspergillus flavus).
The potential of spice oils in the control of mycotoxin producing fungi
(2000) Juglal, Sarla; Odhav, Bharti
Spice oils are known to exhibit antifungal activity and therefore have the potential to control mycotoxin production. There is a need in the food industry to find measures to control mycotoxins that are frequently associated with grains that form the staple diet of the majority of the population in South Africa. Clove, cinnamon, oregano, tumeric, eucalyptus, neem, aniseed, mace and nutmeg oils were tested to determine their inhibitory potential against growth of Aspergillus parasiticus and Fusarium moniliforme using the agar overlay technique. Varying concentrations of the spice oils, ranging from 0.1 ppm to 2.0 ppm, were incorporated into broth cultures of A. parasiticus and maize patty cultures ofF. moniliforme. Levels of production of aflatoxins and fumonisin were determined using standard thin layer chromatography and highpressure liquid chromatography methods. In addition, the active component of the spice oils were isolated, characterised and tested. The inhibitory potential of these compounds for field use was tested by incorporating clove oil, whole cloves and ground cloves in samp