This research focuses on the evaluation of many aspects of the American Wood Protection Association (AWPA) Standard E1-97, “Standard Method for Laboratory Evaluation to Determine Resistance to Subterranean Termites.” This standard is used extensively for testing the efficacy of new products and preservative systems against subterranean termite species. Research was done to determine what changes, if any, are needed for testing against subterranean termite species such as Coptotermes formosanus (Shiraki) and species of native termite genus Reticulitermes (Holmgren), primarily R. flavipes (Kollar). Variables from the current standard were tested to determine effects of parameters such as moisture of sand substrate; size, type, and location of test material within a test bottle; and termite number and ratios of workers to soldiers per test bottle. Research also improved comprehension of termite biology in a laboratory setting, enabling researchers to develop new and safer control methods.

Hazard Analysis Critical Control Point (HACCP) regulations for juice manufacture require the application of a process that will result in a 5-log reduction (99.999%) of the pertinent pathogen in the juice being processed. The use of ultraviolet (UV) light, as an alternative to traditional thermal processing, has been adopted by some juice processors as a means of meeting the HACCP 5-log performance standard. However, little research had been performed to determine the effect of UV when used in combination with antimicrobial agents that are commonly added to juice products. Therefore, the objectives of this work were (1) to determine if chemical preservatives and ultraviolet light have a combined effect on the reduction of Escherichia coli in apple cider, and (2) to determine the influence of adding chemical preservatives at different points in the processing of juice (i.e., either prior to or after ultraviolet light processing) on the reduction of Escherichia coli in apple cider. In this study, refrigerated (4°C) pasteurized apple cider that contained no added preservatives was inoculated with E. coli ATCC 25922, a surrogate strain for E. coli O157:H7, and exposed to UV (peak output: 254 nm). The following chemical preservatives were added to apple cider either prior to or after UV exposure: dimethyl dicarbonate (75 and 150 ppm), hydrogen peroxide (75 and 150 ppm), potassium sorbate (1000 and 2000 ppm), and sodium benzoate (1000 and 2000 ppm). Following UV exposure and chemical preservative application, inoculated juices were stored at 4°C for 72 hours. Samples were collected prior to and immediately after UV exposure and at 24, 48, and 72 hours of storage. At each sampling point, juice portions (0.1 ml) were serially diluted in peptone diluent (0.1%) and surface plated onto Tryptic Soy Agar (TSA). Counts of the bacterial colonies were made 48 hours after incubating plates at 35°C. Overall, reductions of E. coli were greater in cider treated with preservatives after UV processing than when preservatives were added prior to UV processing (P < 0.05). Furthermore, dimethyl dicarbonate and hydrogen peroxide were more effective than potassium sorbate and sodium benzoate in reducing E. coli populations in conjunction with UV (P < 0.05). When added prior to UV exposure, potassium sorbate was the least effective, allowing for the greatest survival (P < 0.05). This study describes the use of UV in conjunction with hydrogen peroxide and dimethyl dicarbonate as an effective method for producing a 5-log or greater reduction of E. coli O157:H7 in apple cider. / Master of Science

A study was undertaken during June through September, 1981, in which the periphyton from ten locations in Culpeper, Virginia, were analyzed for arsenic, chromium, and copper, both upstream and downstream from the source of contamination. The periphyton primary productivity, chlorophyll-a content, and autotrophic index were also determined. Water samples were analyzed for the three metals; arsenic, chromium, and copper. The highest mean periphyton arsenic and chromium concentration occurred at the station 1.2 miles below the site of contamination. The copper concentration in the periphyton was highest 2.7 miles below the area of contamination. All three periphyton metal concentrations were dependent upon the location of the sampling site, but only the periphyton copper content was dependent upon the date of sampling. All three periphyton metal concentrations below the spill site were higher than normal concentrations found in uncontaminated periphyton. Periphyton primary productivity was greatest at the station above the spill site and lowest at the site 1.2 miles below the site of contamination. A negative correlation was observed between the productivity and the periphyton chromium concentration. No other relationships were noted. The chlorophyll-a level in the periphyton was dependent only upon the date of sampling, not on the location of the sampling site. No relationships were observed between the chlorophyll-a levels and any of the three metals' concentrations in the periphyton. The autotrophic indices, the ratio of the organic matter to the periphyton chlorophyll-a concentration, were very high at all stations, indicating organically polluted water. Both the location and date of sampling significantly affected the autrophic index. / Master of Science

This study was designed to investigate potential environmental effects of stream contamination resulting from a spill by Culpeper Wood Preservers, Culpeper, Virginia. The objective was to determine the concentrations of arsenic, chromium, and copper in the sediments of streams affected by the spill and by runoff from a landfill site. The variations in metal concentrations were studied as functions of depth within the stream bed, as functions of distance from the source of contamination, and with passage of time. Sediments from several locations along the streams were extracted with Hcl and analyzed to determine metals concentrations. A microcosm experiment was conducted also to determine whether metals in the sediments would be released to the water under anaerobic conditions. Concentrations as high as 16 ppm for arsenic and 114 ppm for chromium were found in the sediment downstream of Culpeper Wood Preservers. Copper levels were not significantly higher than natural levels. Little difference was found between concentrations of shallow and deeper sediments. Downstream from the landfill site, metal concentrations were not significantly greater than natural concentrations for most sampling locations. In the microcosm experiments, chromium and copper were not released from the sediment. Arsenic concentrations in the water initially increased, then declined. The major conclusion of the study was that the metals appeared to be bound in the sediment and, except for potential releases of arsenic in anaerobic pools during low flow conditions, they should remain in the bound state. / M.S.

Studies were conducted on the penetration and permanence of 1.0% chlorpyrifos [0,0-diethyl 0-(3,5,6-trichloro-2-pyridyl) phosphorothioate], formulated as Dursban® TC (Dow Chemical Co.), in pine (Pinus spp.), spruce (Picea spp.), and fir (Abies spp.). Results indicated the highest degree of penetration in southern yellow pine. Surface roughness and orientation had an effect upon chemical penetration. Longevity studies ranging over time periods from three to 52 months revealed rapid loss of chlorpyrifos from the surface of the wood but relatively stable below-surface concentrations. Similar studies with 0.5% permethrin [(3-phenoxypheny]) methyl] (+) - cis, trans-3-(2,2-dichloroethenyl)-2,2dimethylcyclopropane-carboxylate] applied to the same wood types revealed comparable penetration differentials between types of wood. Formulation differences had little significant effect on penetration. One-year longevity studies revealed surface losses less drastic than those reported for chlorpyrifos, as well as superior below-surface stability. Studies employing volumes five, 10, and 25 times less than that required to achieve a runoff application revealed significantly lower chlorpyrifos penetration with reduced volume. Some reduced volumes resulted in below-surface concentrations of chlorpyrifos higher than the LC₉₀ value for Hylotrupes bajulus (Coleoptera: Cerambycidae). Toxicity testing with chlorpyrifos on first-instar larvae of H. bajulus, the old house borer, revealed contact LC₅₀ and LC₉₀ values of 14 ppm and 78 ppm, respectively. Similar tests with permethrin indicated LC₅₀ and LC₉₀ values of 2 ppm and 8 ppm. Tests with first-instar larvae on wood treated with 1.0% chlorpyrifos and 0.5% permethrin resulted in 100% mortality on wood aged for nine months in the case of chlorpyrifos, and six months in the case of permethrin. Tests utilizing H. bajulus eggs placed on treated wood revealed ovicidal properties of permethrin and lack of ovicidal effect with chlorpyrifos. Accelerated ageing studies employing an environmental chamber (40°C, 70% RH) at a 1:6 ratio of accelerated to natural weathering indicated no significant difference in surface or below-surface concentrations of permethrin in wood aged artificially for one month and in wood aged naturally for six months. Similar results were obtained with chlorpyrifos-treated wood artificially aged for 10 months and aged naturally for 4-1/3 years. Mathematical models were developed to predict surface and one millimeter concentrations of chlorpyrifos and permethrin after five and 10 years. / Ph. D.

Wood-based panel products (WBPs) are considered highly sustainable due to their carbon neutrality, low embodied energy, and ability to be produced from various low-grade wood species. However, WBPs exhibit limited resistance to biological degradation, which can deteriorate their mechanical performance and shorten their service life. Additionally, WBPs may not be fully compatible with traditional wood preservation chemicals. This dissertation demonstrated a facile method of synthesizing essential oil-based natural preservatives compatible with WBPs. Four essential oils (EOs), namely thymol (THY), trans-cinnamaldehyde (tCN), carvacrol (CRV), and eugenol (EUG), were complexed with beta-cyclodextrin (beta-CD) to form beta-CD-EOs inclusion complexes through a sonochemical process using a high-power ultrasonicator (750W). The sonochemical variables, such as a molar ratio between beta-CD and EO, ultrasonication power, and centrifugation speed and time, were optimized to improve the inclusion yield of EOs in the complex and facilitate the large-scale production of beta-CD-EOs. Attenuated Fourier transform infrared spectroscopy (AT-FTIR) and X-ray diffraction analysis confirmed the formation of inclusion complexes at the different production scales. The inclusion yield of EOs in the complexes was estimated by ultraviolet-visible spectrophotometry (UV-vis) as well as thermogravimetric analysis (TGA), which was capable of differentiating unreacted EOs and loosely encapsulated EO molecules from the estimation of the inclusion yield. Differential scanning calorimetry (DSC) revealed that beta-CD-tCN did not adversely affect the curing properties of polymeric methylene diisocyanate (pMDI) used as a glue for plywood. The influence of beta-CD-tCN addition on the bonding strength of the wood composite was assessed by a lap shear strength test using 3-ply SYP plywood, following ASTM D906-20. Statistical analysis using the Tukey test at p<=0.05 indicated no significant difference between the bonding strength of pMDI and beta-CD-tCN as an additive, indicating that beta-CD-tCN could be successfully implemented in the manufacturing process of wood composite products as natural preservatives.

Inledning En tredjedel av den mat som produceras i världen slängs (United Nations Development Programme [UNDP], 2020) och de livsmedelsförstörande mikroorganismerna är ett vanligt förekommande problem och en bidragande orsak till det globala matsvinnet (Snyder &amp; Worobo, 2018). Livsmedelsindustrin använder därför olika hurdletekniker för att minimera risken för tillväxt av förskämningsorganismer (Snyder &amp; Worobo, 2018). En strategi för att kontrollera om olika hurdletekniker uppfyller sitt syfte är att utsätta ett livsmedel för ett belastningstest. Syfte Syftet med studien var att genom ett belastningstest i ett flytande livsmedel jämföra konserveringsmedlen lingonjuice och kaliumsorbat + natriumbensoat samt att undersöka produktens fysikaliska och kemiska förändringar över tid.  Material och metod Ett flytande livsmedel (n = 73 á 180 ml) inokulerades i ett belastningstest med log 2–3 mikroorganismer per ml livsmedel. Därefter tillsattes konserveringsmedlen lingonjuice (n = 24) eller kaliumsorbat + natriumbensoat (n = 25). En tredjedel av proverna (n = 24) lämnades utan konserveringsmedel. Provtagning för analys av tillväxt, färg, pH och viskositet (mPas) utfördes vid 0, 14 och 30 dagar efter livsmedlet inokulerats med mikroorganismer.   Resultat Resultatet visade mikrobiell tillväxt i samtliga livsmedel vid dag 0. Dag 14 identifierades tillväxt i livsmedlet med kaliumsorbat + natriumbensoat samt lingonjuice. Vid analysen på dag 30 identifierades tillväxt i livsmedlet med kaliumsorbat + natriumbensoat och i livsmedlet utan konserveringsmedel. Över tiden skedde även fysikaliska förändringar i viskositet och kemiska förändringar av pH-värdet. Gällande färg skedde enbart marginella förändringar. Slutsats Resultatet av belastningstestet visade att lingonjuice är det konserveringsmedel som har bäst effekt med avseende på produktstabilitet genom att hämma tillväxt av tillsatta mikroorganismer. Resultaten av de fysikaliska mätningarna visade på förändringar över tid med avseende på viskositet. Färg visade enbart minimala förändringar. Resultatet av den kemiska mätningen visade på förändringar av pH-värdet över tid. / Introduction One third of food produced in the world is discarded (United Nations Development Program [UNDP], 2020) and food-destroying microorganisms are a common problem and a contributing cause of global food waste (Snyder &amp; Worobo, 2018). The food industry therefore uses various hurdle techniques to minimize the risk of growth of spoilage organisms (Snyder &amp; Worobo, 2018). One strategy to check whether different hurdle techniques meet their purpose is to expose foods in a challenge test. Aim The aim of the study was to compare the preservatives lingonberry juice and potassium sorbate + sodium benzoate and examine any physical and chemical changes over time through a challenge test on a liquid food product. Material and method A liquid food (n = 73 á 180 ml) was inoculated in a challenge test with log 2-3 microorganisms per ml food. Thereafter preservatives lingonberry juice (n = 24) or potassium sorbate + sodium benzoate (n = 25) were added. One third of the samples (n = 24) were left without preservatives. Sampling for analysis of growth, color, pH and viscosity (mPas) was performed at 0, 14 and 30 days after the food was inoculated with microorganisms. Results The results showed microbiological growth in all food products at day 0. Day 14 growth were found in the food with potassium sorbate + sodium benzoate and lingonberry juice. By the analysis on day 30 growth in the food with potassium sorbate + sodium benzoate and in the food without preservatives were showed. Over time physical changes of viscosity and chemical changes of pH occurred. Regard to color only marginal changes occurred. Conclusion The result of the challenge test showed that lingonberry juice is the preservative that has the best effect regard to product stability through inhibiting the added microorganisms. The results of the physical measurements showed changes regard to viscosity over time. Color only showed marginal changes. The result of the chemical measurement showed changes of pH over time.

A produção de resíduos pelas indústrias alimentícias têm se tornado um problema ambiental. Esses subprodutos sem o devido descarte se acumulam no meio ambiente causando poluição que leva a contaminações que podem provocar danos ao organismo humano. A sustentabilidade deve ser prioritária para o setor de processamento alimentício, realizando o aproveitamento de qualquer despejo industrial que possa se transformar em foco de contaminação ambiental. A cebola (Allium cepa L.) é um dos vegetais mais consumidos mundialmente, e em consequência disso, seu processamento gera uma grande quantidade de resíduos. A casca desse alimento apresenta teores consideráveis de flavonoides, compostos bioativos de elevada capacidade antioxidante. A transformação desse resíduo em um produto de fácil utilização e que possa agregar valor à matrizes alimentares torna-se uma alternativa para utilização desse resíduo que até então não apresenta um aproveitamento valioso para o setor alimentício. Três variedades de casca de cebola foram processadas na forma de pós e analisadas quanto a sua composição química e quanto à sua ação antioxidante. O produto elaborado que apresentou maior capacidade antioxidante foi o pó de casca de cebola roxa que em seguida foi adicionado ao produto cárneo de frango para avaliar seu potencial frente à oxidação lipídica. Houve o controle na estabilidade oxidativa do produto, porém a adição do conservante natural alterou os parâmetros de cor das almôndegas de frango, tornando mais escura a coloração do produto. Diante do exposto, a elaboração do produto a partir do resíduo da cebola pode se constituir em uma alternativa viável aos produtos sintéticos utilizados para fins da conservação em produtos cárneos uma vez que mostrou-se um potencial antioxidante. / Waste production by food industries have become a serious environmental problem. These by-products without proper disposal may accumulate in the environment causing pollution or contamination that may cause damage to the human body. Sustainability should be a priority in processing food sector, realizing use of any industrial dump it can become the focus of environmental contamination. The onion (Allium cepa l.) is one of the most consumed vegetable worldwide, and as a consequence, its processing generates a large amount of waste. The peel of this food has considerable amounts of flavonoids, bioactive compounds of high antioxidant capacity. The transformation of this waste in an easy-to-use product that can add value to food matrices becomes an alternative to the use of this waste that does not present a valuable use for the food industry. Three varieties of onion peel were processed as into powders and their chemical composition, mainly antioxidant activity were analysed. In the present study, the elaborated product that showed the highest antioxidant capacity was the purple onion peel powder which was added to the meat product processed chicken to assess its potential against lipid oxidation. There was the fat decay control of the product, however the addition of natural preservative caused differences in the color parameters of chicken meatballs, making the darker the color of the product. Therefore, the elaboration of a product from the onion waste was a viable alternative to synthetic products used for conservation purposes in meat products and proved to be a potential antioxidant.

Um dos grandes desafios no desenvolvimento de fórmulas farmacêuticas e cosméticas é a adequação de seus sistemas conservantes. No presente trabalho, empregou-se método de otimização destes para suspensão oftálmica de dexametasona e sulfato de polimixina B. O experimento foi conduzido utilizando-se planejamento estatístico do tipo simplex-lattice. A matriz de ensaio contemplou 17 fórmulas sendo que as variáveis independentes foram as concentrações de conservantes álcool feniletílico (X1) e digluconato de clorhexidina (X2) e EDTA (X3). A variável dependente ou resposta foi o valor D obtido do desafio das fórmulas com Pseudomonas aeruginosa, Pseudomonas cepacia, Staphy/ococcus aureus, Candida albicans e Aspergillus niger, empregando-se nas determinações, o Método de Regressão Linear. A análise estatística dos resultados, para cada microrganismo desafiante, conduziu à equações que expressaram matematicamente o fenômeno observado. Como conseqüência, foi possível o cálculo teórico do valor D em função das concentrações das variáveis independentes. Além das equações, obtiveram-se as superfícies de resposta e gráficos de contorno correspondentes aos ensaios, para cada germe. Para a seleção da fórmula ou região que atendesse o critério adotado e que conciliasse as condições ideais e factíveis (D &#8804; 4 horas, para bactérias e D &#8804; 28 horas, para fungos) utilizaram-se duas estratégias: gráfica e numérica. A primeira consistiu na sobreposição dos gráficos de contorno resultando em região da qual selecionou-se, aleatoriamente, a fórmula empregando X1 = 0,10; X2 = 0,80; X3 = 0,10. A segunda, baseou-se na aplicação da função \"desejo\", tendo sido a fórmula ideal resultante de cálculos desenvolvidos, a partir de premissas, sendo: X1 = 0,25; X2= 0,75; X3= 0,0. Ambas as fórmulas, derivadas das estratégias empregadas, foram submetidas à avaliação de seus sistemas conservantes 232 pelo método de Regressão Linear. Os valores D obtidos foram semelhantes àqueles calculados por meio das equações anteriormente mencionadas, exceto para Staphy/ococcus aureus. A aplicação de métodos de otimização estatística permitiu, de forma racional, atingir o objetivo fixado. Através dessas técnicas, tornou-se possível a definição de regiões experimentais em melhores condições, demonstrando vantagens no uso do álcool feniletílico, bem como um melhor conhecimento dos mecanismos envolvidos. / One of the greatest challenges in pharmaceutical and cosmetic formulations consist of the development of adequate preservative systems. Whose optimized development was preposed for ophthalmic suspension of dexametasone and polymyxin B. This was performed threugh simplex-lattice method. The matrix of essay completed 17 formulas, from which independent variables were the preservative concentrations: phenylethanol (X1), chlorhexidine digluconate (X2) and EDTA (X3). The dependent variable was the D-value obtained from the challenge of those formulas with Pseudomonas aeruginosa, Pseudomonas cepacia, Staphhylococcus aureus, Candida albicans and Aspergillus niger, ali result of the Linear Regression Method. The statistical analysis employment led to polynomial expressions which expressed mathematically the observed behavior in each organismo As a consequence the theoretical calculation of the D-value considering ali the independent variables was possible. Besides these expressions, the response surfaces and the contour graphics corresponding to the essays, for each microorganism, were obtained. To the formula or region selection which better complied to the adopted criteria and conciliated ideal and realistic conditions (D &#8804; 4 hours, for bacteria and D &#8804; 28 hours, for fungi) both graphic and numeric strategies were used. The former consisted of the superposition of contour graphics of each micreorganism, what resulted in a region from which the formula was randomly selected using X1 = 0,10; X2 = 0,80; X3 = 0,10. The latter was based on the application of \"wish\" function, and the ideal formula obtained from calculations developed from these premisses: X1 = 0,25, X2 = 0,75; X3 = 0,0. Both formulas, derived from the employed strategies were submitted to evaluation of their preservative systems by Linear Regression Method. The D-values obtained were similar to those calculated through the previously mentioned expressions, except for Staphylococcus aureus. The application of optimized statistical methods enabled us, in a rational way, to achieve the fixed goal. Through these techniques, both experimental regions in better conditions, demonstrating advantages of using of the involved mechanisms were attained.

Um dos grandes desafios no desenvolvimento de fórmulas farmacêuticas e cosméticas é a adequação de seus sistemas conservantes. No presente trabalho, empregou-se método de otimização destes para suspensão oftálmica de dexametasona e sulfato de polimixina B. O experimento foi conduzido utilizando-se planejamento estatístico do tipo simplex-lattice. A matriz de ensaio contemplou 17 fórmulas sendo que as variáveis independentes foram as concentrações de conservantes álcool feniletílico (X1) e digluconato de clorhexidina (X2) e EDTA (X3). A variável dependente ou resposta foi o valor D obtido do desafio das fórmulas com Pseudomonas aeruginosa, Pseudomonas cepacia, Staphy/ococcus aureus, Candida albicans e Aspergillus niger, empregando-se nas determinações, o Método de Regressão Linear. A análise estatística dos resultados, para cada microrganismo desafiante, conduziu à equações que expressaram matematicamente o fenômeno observado. Como conseqüência, foi possível o cálculo teórico do valor D em função das concentrações das variáveis independentes. Além das equações, obtiveram-se as superfícies de resposta e gráficos de contorno correspondentes aos ensaios, para cada germe. Para a seleção da fórmula ou região que atendesse o critério adotado e que conciliasse as condições ideais e factíveis (D &#8804; 4 horas, para bactérias e D &#8804; 28 horas, para fungos) utilizaram-se duas estratégias: gráfica e numérica. A primeira consistiu na sobreposição dos gráficos de contorno resultando em região da qual selecionou-se, aleatoriamente, a fórmula empregando X1 = 0,10; X2 = 0,80; X3 = 0,10. A segunda, baseou-se na aplicação da função \"desejo\", tendo sido a fórmula ideal resultante de cálculos desenvolvidos, a partir de premissas, sendo: X1 = 0,25; X2= 0,75; X3= 0,0. Ambas as fórmulas, derivadas das estratégias empregadas, foram submetidas à avaliação de seus sistemas conservantes 232 pelo método de Regressão Linear. Os valores D obtidos foram semelhantes àqueles calculados por meio das equações anteriormente mencionadas, exceto para Staphy/ococcus aureus. A aplicação de métodos de otimização estatística permitiu, de forma racional, atingir o objetivo fixado. Através dessas técnicas, tornou-se possível a definição de regiões experimentais em melhores condições, demonstrando vantagens no uso do álcool feniletílico, bem como um melhor conhecimento dos mecanismos envolvidos. / One of the greatest challenges in pharmaceutical and cosmetic formulations consist of the development of adequate preservative systems. Whose optimized development was preposed for ophthalmic suspension of dexametasone and polymyxin B. This was performed threugh simplex-lattice method. The matrix of essay completed 17 formulas, from which independent variables were the preservative concentrations: phenylethanol (X1), chlorhexidine digluconate (X2) and EDTA (X3). The dependent variable was the D-value obtained from the challenge of those formulas with Pseudomonas aeruginosa, Pseudomonas cepacia, Staphhylococcus aureus, Candida albicans and Aspergillus niger, ali result of the Linear Regression Method. The statistical analysis employment led to polynomial expressions which expressed mathematically the observed behavior in each organismo As a consequence the theoretical calculation of the D-value considering ali the independent variables was possible. Besides these expressions, the response surfaces and the contour graphics corresponding to the essays, for each microorganism, were obtained. To the formula or region selection which better complied to the adopted criteria and conciliated ideal and realistic conditions (D &#8804; 4 hours, for bacteria and D &#8804; 28 hours, for fungi) both graphic and numeric strategies were used. The former consisted of the superposition of contour graphics of each micreorganism, what resulted in a region from which the formula was randomly selected using X1 = 0,10; X2 = 0,80; X3 = 0,10. The latter was based on the application of \"wish\" function, and the ideal formula obtained from calculations developed from these premisses: X1 = 0,25, X2 = 0,75; X3 = 0,0. Both formulas, derived from the employed strategies were submitted to evaluation of their preservative systems by Linear Regression Method. The D-values obtained were similar to those calculated through the previously mentioned expressions, except for Staphylococcus aureus. The application of optimized statistical methods enabled us, in a rational way, to achieve the fixed goal. Through these techniques, both experimental regions in better conditions, demonstrating advantages of using of the involved mechanisms were attained.