The objective of this study was to investigate the differences in survival of L. monocytogenes EGD (Bug600) (serotype 1/2a) in various disinfectants and essential oils after sublethal heat stress at 48°C for 60 min. The survival of heat stressed L. monocytogenes cells was decreased in lethal acid (HCl or H3PO4 pH 2.5), lethal oxidative stress (H2O2 1000 ppm) and lethal quaternary ammonium compounds (QAC 2.5-3.5 ppm) compared to non-stressed control cells. By contrast, the survival of heat stressed L. monocytogenes cells was higher in lethal alkali (NaOH or KOH pH 12) than the control cells. Also, the survival of heat stressed L. monocytogenes cells was higher in lethal carvacrol (428 ppm) and bay oil (1100 ppm) but was decreased in lethal red thyme oil (300 pm) compared to control. These findings indicate that the heat stressed cells of L. monocytogenes are not easily killed by alkali-based disinfectants and essential oils containing carvacrol and bay oil. Therefore, disinfectants and essential treatments should be carefully considered when heat stressed cells of L. monocytogenes may be present.

The present work examines the antimicrobial efficacy of the essential oils of thyme, oregano and carvacrol against L. monocytogenes biofilms produced on stainless steel coupons and for control of L. monocytogenes growth on raw catfish fillets stored at 4°C for 10 days. At 0.5%, all three essential oils were highly effective in completely eliminating L. monocytogenes cells from stainless coupons within 24 h as compared to the untreated control yielding ~7 log CFU/cm2 L. monocytogenes. When catfish inoculated with L. monocytogenes were dipped for 30 min at 4°C in essential oil solutions of thyme and oregano at 1%, 2% and 5%, there were no significant reductions in L. monocytogenes counts on the fresh catfish fillets as compared to untreated control. For the same conditions, treatment with 2% carvacrol resulted in a complete reduction of 4 log CFU/g of L. monocytogenes counts from fresh catfish fillets.

No description available.

In this study, potential of high hydrostatic pressure (HHP) and essential oils (EOs) as natural antimicrobials was evaluated to produce E. coli safe and quality beef product. First, the individual and combined effects of antimicrobial activity (minimum inhibitory concentration) of basil, black cumin, cilantro, cumin, fenugreek, ginger, oregano, black pepper, rosemary, thyme, turmeric oil emulsions on E. coli ATCC 25922 with and without HHP treatment were evaluated. Cumin, oregano and thyme EOs showed highest antimicrobial activity against E. coli ATCC 25922. The synergy of selected EOs against E. coli ATCC 25922 was determined using the checkerboard method to obtain fractional inhibitory concentration index. Although their combinations did not show synergy, they expressed synergy when combined with HHP (400 MPa, 10 min, 20 °C) and the best combination was cumin and oregano EOs with HHP. Effects of HHP and EO combinations on inactivation of E. coli ATCC 25922 in beef were investigated using response surface methodology (RSM). Statistical analysis showed the model was significant for predicting log reduction with high accuracy. The significant model terms were pressure and time. Compared to control, HHP/EO treated samples showed no-post growth when stored up to 120 days at 4°C. Presented results suggests that the combination of HHP and antimicrobials has not only improved the process parameters (lowered pressure, time, and EO concentration) but also prevented recovery of E. coli ATCC 25922 during storage. RSM was employed to analyze the synergistic effects of HHP and EOs on beef quality (color, texture and lipid oxidation). Color indices were significantly affected by pressure, time and their interactions. Above 400 MPa the discoloration was similar to cooked beef and EO addition did not help color improvement. However, EOs showed significant antioxidant activity on both treated and untreated samples during storage. In conclusion, there is a great potential of HHP and EO combinations to enhance pathogen inactivation while keeping the quality of beef. Moreover, presence of EOs can prolong the shelf life of pressure treated beef. Therefore, the combination of HHP and EO is very promising for meat industry. / Ph. D.

by Lam Shiu Ying Sati. / Thesis (M.B.A.)--Chinese University of Hong Kong, 1999. / Includes bibliographical references (leaves 56-57). / Questionnaire also in Chinese. / Chapter I. --- introduction --- p.1 / Definition of Aromatherapy --- p.1 / Uses of Aromatherapy --- p.2 / Aromatherapy as Alternative Natural Healing --- p.3 / Aromatherapy in Hong Kong --- p.4 / Objective of the Project --- p.5 / Chapter II. --- ENVIRONMENT --- p.7 / brief History of Aromatherapy --- p.7 / Social and Legal Environment on Aromatherapy in the World and Hong Kong --- p.8 / Social Issues --- p.9 / Legal Issues on Selling Essential Oils --- p.11 / Qualification of Aromatherapists --- p.13 / Chapter III. --- INDUSTRY --- p.15 / Aromatherapy Related Products --- p.15 / Market Players in Hong Kong --- p.17 / Chapter IV. --- MARKETING STRATEGIES --- p.26 / The Company --- p.26 / Market Opportunities --- p.28 / Marketing Strategies of Company ABC --- p.29 / Position of Company ABC --- p.29 / Product and Price Considerations --- p.30 / Promotion and Channel Considerations --- p.31 / Potential Problems and Constraints --- p.34 / Chapter V. --- MARKET SURVEY --- p.35 / Chapter VI. --- CONCLUSION --- p.42 / APPENDIX --- p.46 / BIBLIOGRAPHY --- p.56

Eastern Cape Province farmers in the natural essential oils industry are yet to fully realise the use of electronic commerce (e-commerce) platforms, such as electronic marketplaces (e-marketplaces) for business purposes. This is due to the issues that include lack of awareness, poor product quality, untrusted payment gateways and unsuccessful delivery that are associated with e-marketplaces. As a result, farmers do not trust e-marketplaces and therefore hesitate to engage in e-marketplaces for business purposes. This is further complicated by natural essential oils buyers‟ tendency of preferring face-to-face interaction with a supplier rather than online interaction as they need quality assurance. As such, this research proposes a model to enhance the perceived trustworthiness of natural essential oil producers in the Eastern Cape Province selling through e-marketplaces. The model constitutes the factors that could be considered in assisting essential oil producers to create a perception of trustworthiness to buyers in e-marketplaces. These factors were evaluated amongst five organisations involved in the production, retail or processing of essential oils using a multiple-case study methodology. The study‟s use of multiple-case study was applied within the interpretivist paradigm and five cases were considered. Interviews, document analysis and observations were used for data collection. Data analysis was done using within-case analysis followed by cross-case analysis to establish factors of trust. The essential oil producers based in the Gauteng, Kwazulu-Natal and Western Cape provinces were cases that had been successfully using e-marketplaces for a notable period of time. Accordingly, factors that contributed to the successful use of e-marketplaces informed the proposed model of this research. The model proposes that perceived trustworthiness of enterprises in e-marketplaces can be achieved through following the uncertainty reduction stages (Entry, Personal and Exit) and applying uncertainty reduction strategies (passive, active and interactive).

Thesis (M.Tech.: Biotechnology)-Dept. of Biotechnology, Durban University of Technology, 2007 xv, 136 leaves / The chemical and biological properties of the essential oil from Cymbopogon validus were investigated. Hydro-distillation was used to extract the oil from C. validus, the flower-heads, leaves, culms and rhizomes. The percentage oil yields obtained from the plant organs varied from 0.05 to 1.23%, with the greatest concentration found in the flower-heads and rhizomes, 1.23 and 1.12% respectively. A sensory evaluation of the oil revealed that the essential oil was slightly murky, pale yellow in colour, had a strong turpentine-like smell and remained liquid at room temperature. The oxidative stability of C. validus oil was evaluated by determining its Rancimat induction period (negative), peroxide value (60.56 meq/kg), iodine value (84.55), percentage free fatty acids (0.19%) and percentage cholesterol (3.03%). These results indicated that the oil was highly susceptible to oxidation. Chromatographic profiles of the oils from C. validus, as well as the plant organs were generated using gas chromatography-mass spectroscopy (GC-MS). Predominant compounds present in the oil included alpha-Cubebene, Camphene, Geraniol, Limonene, Myrcene, Palmitic acid and Sabinene. C. validus essential oil was also investigated for its antimicrobial (disk diffusion), antioxidant (1, 1-Diphenyl-1-Picrylhydrazyl (DPPH) assay), anti-inflammatory (5-lipoxygenase assay), anti-mosquito properties (insecticidal, larvicidal and repellency assays) and toxicity profile (Brine shrimp and Ames assays). The oil showed poor antimicrobial activity and inhibited the growth of only Gram positive bacteria with a minimum inhibitory concentration (MIC) of 0.0625 (vol/vol) for Bacillus, Micrococcus and Staphylococcus species. The oil also exhibited excellent antioxidant activity, scavenging more than 80% of DPPH free radicals and possesses anti-inflammatory activity (IC50=190 ppm). C. validus oil showed good adulticidal activity (53.7% mortality) and excellent larvicidal (100% mortality) and repellent activity (100% repellency) against Anopheles arabiensis mosquitoes. At high concentrations, the oil was toxic to brine shrimp larvae. However, when diluted it was safe and the minimum inhibitory concentration was 0.0001(vol/vol). The absence of revertant colonies at all essential oil concentrations in the Ames test suggest that the oil is not mutagenic. These results lead the way for exploiting C. validus oil as a multi-functional agent that has antibacterial, anti-oxidant, anti-inflammatory, and anti-mosquito properties.

Foodborne pathogens are a threat to public health worldwide. Because many consumers prefer natural compounds to synthetic additives, research on safe plant-derived compounds with antimicrobial activity against foodborne pathogens is vital. The aim of this investigation was to evaluate the antimicrobial activities of plant essential oils (oregano, cinnamon, lemongrass), their active components (carvacrol, trans-cinnamaldehyde, citral) and plant-extracts such as green tea, apple skin extract, black and decaffeinated black tea, grapes seed and pomace extracts against foodborne bacteria. Salmonella enterica serotype Typhimurium DT104, and serotype Newport, were selected conducting an antibiotic screening on 23 Salmonella isolates using seven antibiotics to determine antibiotic resistance. Listeria monocytogenes (strain 101M; beef and pork sausage isolate; resistant to antimicrobials in past investigations) was included to represent gram-positive bacteria. Escherichia coli O157:H7 virulent isolates (932- apple juice isolate; ATCC 35150- human isolate; F4637- sprouts isolate; used as a cocktail) were selected after conducting a Multiplex PCR over nine E. coli O157:H7 isolates to detect shiga-toxin 1 and 2 genes. All antimicrobials were evaluated in vitro in phosphate buffered saline. In general, all pathogens were more susceptible to essential oils and their active components, than powder extracts. The most active antimicrobials from each category were directly applied on foods. The activity of oregano oil (0.5%) and green tea (3%) was evaluated against S. Typhimurium on chicken and S. Newport on tomatoes and sprouts, and the results showed that oregano oil was more effective. In addition, baby spinach leaf samples inoculated with green fluorescent protein labeled S. Newport were examined under confocal scanning laser microscope before and after antimicrobial treatments. Antimicrobial experiments against L. monocytogenes on sprouts, ham and bologna, carvacrol at 0.5% and grape seed extract at 3% were used and carvacrol showed better activity. Antimicrobial activity against E. coli O157:H7 was tested on romaine lettuce, spinach and ground beef using oregano oil at 0.5% and green tea at 3%. Both compounds were effective showing no recovery of E. coli O157:H7 from lettuce and spinach; however, was not reduced in ground beef. Antimicrobial plant compounds have the potential for reducing foodborne pathogenic bacteria on/in various foods.

Mentha longifolia subsp. polyadena was collected from seven localities in South Africa and from a single population in Botswana to study the essential oil composition and antimicrobial activity of this ethnomedicinal plant. The essential oils were obtained by hydrodistillation and analysed by gas chromatography coupled to mass spectroscopy (GC/MS) and a cluster analysis was performed on the essential oil dataset. From eight samples (representing eight natural populations), two major chemotypes were identified: (i) a menthofuran rich type (51.4% - 61.6%); and (ii) a cis-piperitone epoxide (14.7% – 35.7%) and piperitenone oxide (14.6% - 65.7%) rich type. The constituent analysis showed quantitative variation with higher amounts of oxygencontaining monoterpenes ranging from 56.5% to 89.6% whilst the sesquiterpene hydrocarbons ranged from 4.4% to 16.7%. The essential oil from the different localities mostly showed moderate to good antimicrobial activity against Staphylococcus aureus, Staphylococcus epidermidis, Bacillus cereus, Moraxella catarrhalis, Yersinia enterocolitica and Enterococcus faecalis. The oils were generally inactive against Escherichia coli and Salmonella typhimurium. Candida albicans and Cryptococcus neoformans indicated highest sensitivities for oil samples from Komukwane (3 mg/ml and 0.5 mg/ml respectively) and Prins Albert (0.5 mg/ml and 1.6 mg/ml respectively). The HPLC profiles of the methanol and chloroform (1:1) extracts were more conservative and less variable compared to the essential oils. Two major peaks corresponding to retention times of 22.39 min and 26.47 min were present in all eight samples. Most of the solvent extracts displayed moderate to good antimicrobial activity against Gram-positive pathogens, in particular against S. aureus, S. epidermidis and B. cereus with MIC values ranging from 0.5 mg/ml to 2 mg/ml in most cases. The extracts also demonstrated moderate to good activity against most of the Gram-negative pathogens, in particular against Y. eneterocolitica and M. catarrhalis, with MIC values ranging from 0.5 mg/ml to 2 mg/ml. These results may in part provide scientific evidence for the extensive use of Mentha longifolia in traditional healing.

As algas marinhas calcárias (AMC) e os óleos essenciais vêm sendo utilizados como aditivos em dietas para ruminantes. As AMC têm sido adicionadas às dietas com o objetivo de modularem o pH ruminal, enquanto os óleos essenciais, através de sua ação antimicrobiana, têm sido testados como alternativa aos aditivos antibióticos na produção animal. Os objetivos do presente estudo foram avaliar os efeitos de óleos essenciais e de algas marinhas calcárias (AMC), bem como a combinação de ambos, sobre desempenho e ambiente ruminal de vacas leiteiras em lactação. Foram realizados 2 experimentos com 32 vacas leiteiras sob sistema de pastejo rotativo com suplementação diária de 6 kg de alimento concentrado por vaca: o experimento 1 foi de desempenho e o experimento 2 de metabolismo ruminal. Em ambos os experimentos as vacas foram submetidas aos seguintes tratamentos: a) controle (CONT); b) óleos essenciais (OE); c) algas marinhas calcárias (AMC); d) AMC + OE. No experimento 1, as variáveis registradas foram consumo, produção e composição do leite, ganho de peso, condição corporal e parâmetros sanguíneos (glicose e ácidos graxos não esterificados [AGNE]). No experimento 2 foram utilizadas as mesmas 32 vacas em lactação para avaliação dos parâmetros ruminais. Os delineamentos utilizados foram: em quadrados latinos replicados (experimento 1) e em blocos inteiramente casualizados (experimento 2). No experimento 1 o CMS de pasto e os CMS e CMO totais foram maiores para o tratamento AMC em comparação com os tratamentos OE e OE+AMC. Os dados de consumo do tratamento CONT foram não diferiram dos demais tratamentos. As digestibilidades da MS e da MO foram maiores para os tratamentos OE e OE+AMC em comparação com o tratamento AMC. Os dados de digestibilidade do tratamento CONT não diferiram dos demais tratamentos. O escore de condição corporal médio foi maior para o tratamento OE em comparação com os demais, porém os aditivos testados não afetaram as concentrações sanguíneas de AGNE e de glicose. Os dados de produção e de composição do leite não foram afetados pelos aditivos testados, assim como os dados de concentração de energia das dietas, consumo de energia, secreção de energia no leite e eficiência de conversão da energia consumida em energia láctea. No experimento 2, a suplementação com OE aumentou a concentração molar de AGV totais e a de acetato em comparação com os tratamentos CONT e AMC, com valores intermediários e não diferentes para o tratamento OE+AMC. Houve aumento do pH ruminal no tratamento AMC em comparação com o tratamento OE. A inclusão de óleos essenciais e ou algas marinhas não alterou a resposta produtiva de vacas leiteiras, apesar do aumento na concentração de AGV e de pH ruminal respectivamente. / Essential oils (OE) and calcareous marine algae (AMC) are being used in ruminants diets. The AMC has been added to diets with the purpose of regulating the ruminal pH while the OE, due to their antimicrobial properties, had been tested as an alternative to the antibiotic additives used in animal production. The objectives of the current study were to evaluate the effects of OE and AMC as well as their interaction on performance and ruminal environment of lactating dairy cows. Two experiments with 32 cows were developed. The animals were in a rotational grazing system supplemented with 6 kg per cow of concentrate feed. Experiment 1 was designed to evaluate performance whereas experiment 2 for ruminal metabolism. During both experiments, cows were assigned to the followings treatments: a) control (CONT); b) blend of essential oils (OE); calcareous marine algae (AMC); d) AMC+OE. In experiment 1, the registered variables were intake, yield and milk composition, live weight, body condition score and blood parameters (glucose and non-esterified fatty acids, [NEFA]). In experiment 2 the same 32 lactating cows were used to evaluate ruminal parameters. The statistical designs used were: replicated Latin square (experiment1) and randomized complete block design (experiment 2). In experiment 1, grass and total DM and OM intakes were increased in AMC compared to OE and OE+AMC. The intakes observed for CONT did not differ from the other treatments. Digestibility of DM and OM were higher for OE and OE+AMC compared to AMC. Digestibility of CONT did not differ from other treatments. The average BCS was higher for OE, however the tested additives did not affect blood concentration of NEFA and glucose. Milk yield and composition were not affected by additives inclusion as well as energy concentration in diets, energy intake, secreted energy in milk and energy conversion efficiency. In experiment 2, OE increased molar concentration of acetate and total VFA when compared to CONT and AMC, but not differed from OE+AMC. The AMC increased ruminal pH when compared to OE. The inclusion of essential oils and/or calcareous marine algae did not alter the productive response of lactating dairy cows, even though there was an increase in VFA concentration and ruminal pH.