A polarimetric method for monitoring the rate of soluble collagen breakdown by collagenase enzyme action has been developed. The method represents an extension of previous physicochemical techniques based on viscometry, but is simpler and easier to carry out, particularly in the case of reaction rate studies. The method was developed arising from reports of collagenase activity measurement on inappropriate substrates such as gelatin, modified collagens and synthetic polypeptides. The optical method depends on measurement of the loss in optical rotation in solutions of soluble calfskin collagen resulting from initial enzymic cleavage of the collagen trip1e-helix, followed by spontaneous unwinding of the resultant unstable helical fragments. Specific assay conditions were chosen to ensure that the loss in optical rotation following enzymic cleavage was rapid and complete. The method is specific since in the absence of collagenase, non-specific proteinases produce only a limited decrease in solution optical activity. The method has also been compared with established physicochemical assay techniques and compares favourably with both viscometric and titrimetric collagenase assays. The availability of a rapid, sensitive and quantitative procedure for measurement of collagenase activity provides a convenient means for detecting the presence of collagenase in solution and examination of hide bacterial cultures for collagenase production. In addition, a study of biocidal compounds of potential interest in hide preservation for possible inhibitory effects on collagenase is conveniently carried out with the method. Fundamental research into synergistic action in enzymic hydrolysis of collagen is now possible, providing valuable insight into the mechanism of raw hide biodeterioration.

In the leather industry fungicides are often used for the protection of wet-blue leather. These fungicides are usually only sparingly soluble and are therefore formulated together with surfactants in order to increase their solubility and to ensure an even distribution over the surface of the hide after treatment. Solutions containing both fungicides and surfactant are complex. The nature of these solutions was investigated. By means of UV/Vis spectroscopy and viscometry it was shown that the surfactant and fungicides form micelles and mixed micelles in solution. The nature of these micelles and mixed micelles was dependent on the solution temperature as well as on the concentrations of the surfactant and fungicides. At the higher temperatures and concentrations transition to large, possibly rod-shaped, mixed micelles occurred. The interaction between the selected fungicides 2-(thiocyanomethylthio)benzothiazole and n-octyl-4-isothiazol-3-one with bovine skin collagen in the form of both limed and lightly chromed hide powder in the presence of the non ionic surfactant Triton X -100 was investigated. Fungicide uptake was determined by difference measurements on the float solutions at regular intervals during treatment. Binding was rapid with equilibrium being established within the first six hours even for the solutions with the highest surfactant concentration. Binding failed to follow a normal mass-action binding-type isotherm approaching a saturation limit, but increased continuously indicating a co-operative effect whereby binding site affinity actually increased with the amount of ligand bound. Binding was accompanied by a drop in the free surfactant in the solution at the higher biocide levels indicating the formation of complex mixed micelles which bind to the collagen fibres. The uptake and antifungal activity of commercial fomulations of the fungicides on chrome-tanned wet-blue leather was investigated at various treatment temperatures. At lower fungicide treatment concentrations, binding tended to follow a typical mass-action type binding isotherm, increasing slightly with temperature. At higher float concentrations, an inflexion point was apparent beyond which uptake showed a marked increase with concentration. This inflexion point, signifying a change in binding characteristics, occurred at progressively lower concentrations with increasing temperature. Antifungal activity in terms of storage periods to onset of fungal growth was determined on the wet-blue leather cuttings immediately after treatment and drainage and also on sample discs after exhaustive extraction of free fungicide using dichloromethane. Storage performance testing of the various treated wet-blue leathers was carried out by different methods. Residual protective periods showed a curvilinear increase with dosage offer and surface uptake. In the low dosage range treatment temperature had only a relatively slight effect in promoting uptake and improving storage protection. At higher dosages, the influence of temperature on uptake and storage protection was greater due to the increase in surface binding of the fungicides at the elevated temperatures. Only a portion of the fungicide uptake was recovered by direct solvent extraction of the treated wet-blue leather. Solvent extraction reduced storage margins. The storage response in relation to fungicide content was, however comparable after extraction, indicating that both irreversibly bound and physically associated fungicide offered effective protection. Results of the study provide further insight into the mode of interaction of fungicide emulsion dispersion with bovine skin collagen, and the importance of the emulsion dispersions and its stability in determining the uptake of fungicide.

Animal hides are the basic raw material of the leather industry and they undergo rapid putrefaction unless "cured". This study investigated the role and interactive effects of three selected bacteria, Pseudomonas aeruginosa. Clostridium histoly ticum and Clostridium sporogenes in in-situ cattle hide degradation using a model system set up for the purpose. The system consisted of 3cm diameter hide pieces contained in sealed jars and sterilised by ethylene oxide to remove resident microbes and inactivate autolytic tissue enzymes. The inocula were prepared either as individual cultures or as combinations of two inocula or all three inocula. Degradative changes during storage at 30°C were measured for up to 8 days using ten different parameters. Initial trials confirmed that the selected inocula were readily isolated from raw hides and could outcompete resident populations to produce putrefactive decomposition. Growth rates and enzyme profiles of the organisms and the effects of nutrients and reductants on their relative denaturative effects were used to standardise the system. Trials on the effects of ethylene oxide indicated the suitability of the method for hide and collagen sterilisation. The findings of in-situ trials with the selected inocula confirmed previous studies of protein putrefaction in that a bacterial succession was evident involving aerobic proteolytic bacteria, micro-aerophilic proteolytic bacteria and strictly anaerobic amino acid degrading bacteria. However, this study showed that the micro-aerophilic collagenase producing C. histolyticum degraded hides at a far greater rate when inoculated on its own than when in the presence of either or both of the other two inocula. It also demonstrated a bacterial antagonism between the two clostridia in which C. sporogenes prevented degradative changes occurring for up to 4-6 days possibly due to cysteine production by C. sporogenes. These findings have implications for hide preservation since maintenance of aerobic conditions and suppression of spore outgrowth could be used to delay growth of collagenase producing clostridia. The use of C. sporogenes as a biocontrol agent is also postulated. The model system was also used to examine salted hides during storage and these studies indicated that Halobacteriaceae do not produce collagenase but that inadequately salted hides could possibly be subject to degradation by delsulfovibrios.

Although the Afrikaner and Black-headed Persian were used in several previous studies for upgrading with Karakul rams, this study looked at how fast progress could be made to produce good quality marketable pelts as well as producing ewe material to increase Karakul ewe numbers. Market requirements have also changed in the past years. After three generations of upgrading it was found that, especially in colour inheritance, faster progress was made as in previous studies with just a small percentage of spotted animals (1.3 % in the F₃-generation). All economic important pelt traits (pattern, hair quality, texture, lustre and curl type) improved significantly from the F₁ to the F₃ generation and it compares well with the control group (pure bred black and white Karakul). The type of rams that gave the best results with upgrading, were the less developed type with good hair quality and good pattern forming characteristics (watered-silk and shallow watered-silk). Pelt types improved from the F₁ which were under average and of poor quality to higher quality pelts which received above average prices on auctions for the F₂ and F₃ generations. It appears that the Afrikaner and Black-headed Persian can both be used with success in an upgrading program, all depending on what colour breeding (black or white) there is a need for. / Dissertation (MSc (Agric) (Animal Science))--University of Pretoria, 2007. / Animal and Wildlife Sciences / MSc (Agric) / Unrestricted

In archaeology, most studies of artifacts focus on lithics and ceramics, while bone artifacts are often neglected in our intense study of the past. This thesis takes a step in the opposite direction by focusing on a bone tool known as the beamer. This thesis tests the hypothesis that the beamer, used for processing animal hides, is only used during the Late Woodland and Mississippian time periods. If the hypothesis is supported, the beamer would be unique among bone artifacts, acting as a chronological marker similar to projectile points. The thesis also studies how the hypothesized appearance of the beamer at the beginning of the Late Woodland affected the use of lithic scrapers, another tool used for hide processing. Information gathered for this thesis was used to create a large database of Midwestern prehistoric archaeological sites. While the original hypothesis did not hold up, a new hypothesis was created based on the data. / Department of Anthropology

Thesis (Ph.D.)--Royal Danish Academy of Fine Arts, 2007. / Title from PDF title page (viewed on Oct. 30, 2008). Includes bibliographical references (p. 225-234).

Content: Fine hair is the biggest seasonal challenge for bovine leather production in the United States. The origin, timing and severity of the fine hair problem can be unpredictable and vary from year to year. Seasonal changes on the hair growth cycle are prompted by the lower temperature from fall to winter; the cow hair increases in amount, length and thickness. This problem is very old and has increased in intensity due to changes in the leather manufacturing process, cattle breeding conditions and breed diversity. The amount of fat and thickness of the hide also play important roles. The extent of the problem has not been documented and is not fully understood by the scientific community. The presence of fine hair (residual hair) on the wet blue and final leather are a cause of downgrading the leather. If the wet blue has fine hair, it cannot be removed in further processing in crust or finishing. Some leather types can tolerate more fine hair than others. In this paper we will conduct a scientific evaluation of the fine hair on American bovine hides, wet blue and finished leathers through cross sections and stains, optical and electron microscope observations. We will include measurements of hair thickness and hair depth inside the hide. The work will compare sulfide and oxidative unhairing of winter hides, characterize and show the details of the fine hair through cross sections, and offer indicative measures to minimize the problem. Information from the largest wet blue manufacturer in the US with four tanneries will provide insight on the fine hair seasonality, types of breeds and cattle displacement temperature ranges and will discuss adaptive changes needed in the “Winter” time to control the fine hair. Take-Away: 1) scientific review and evaluation of the problem of fine hair though cross sections and stains, optical and electron microscopy observations 2) evaluate the fine hair on sulfide and oxidative unhairing; providing indicative measures to minimize the problem 3) characterize the seasonality of the fine hair problem regarding the types of breeds, displacement temperature ranges and adaptative changes to control the fine hair

<p>U radu je ispitan i razvijen novi pristup tretmanu kože goveda prirodnom smolom &scaron;elak, koja je dozvoljena za kori&scaron;ćenje u hrani, u cilju redukcije unakrsne mikrobiolo&scaron;ke kontaminacije sa kože na goveđe meso. Mehanizam ovog tretmana je baziran na imobilizaciji mikroorganizama na dlaci tretirane kože i prevenciji njihovog fizičkog prenosa sa dlake na meso trupova tokom procesa obrade zaklanih goveda.<br />U in vitro uslovima, tretman uzoraka vizuelno čiste i suve kože 23% rastvorom &scaron;elaka u etanolu je redukovao prenos sa kože na sunđere kojima je koža uzorkovana brisevima: ukupne mikroflore (TVC) za 6,6 log (&gt;1000 puta vi&scaron;e u odnosu na 2,9 log redukcije kod tretmana samo etanolom), generičke Escherichia coli za najmanje 2,9 i Enterobacteriaceae za najmanje 4,8 log. Ove redukcije sve tri grupe mikroorganizama su bile značajno vi&scaron;e u odnosu na redukcije postignute tretmanom kože kombinacijom ispiranja sanitajzerom i vakumiranja. Značajno vi&scaron;e redukcije prenosa TVC sa kože na sunđerske briseve su postignute kori&scaron;ćenjem vi&scaron;ih koncentracija &scaron;elaka (23% i 30%) u odnosu na niže (4,8-16,7%) i u slučajevima kada je temperatura rastvora &scaron;elaka bila 20, 30 ili 40oC u odnosu na 50oC i 60oC. Takođe, tretman kože &scaron;elakom je značajno (3,7 puta) redukovao prevalencu E. coli O157 na prirodno kontaminiranoj, neinokulisanoj koži, kao i broj E. coli O157 na ve&scaron;tački inokulisanim kožama (redukcija od 2,1 log), u odnosu na odgovarajuće netretirane kontrole.<br />U uslovima laboratorijskog modela direktnog kontakta kože i mesa, tretman kože (različitih kategorija čistoće) 23% rastvorom &scaron;elaka je značajno smanjio prenos mikroorganizama sa tretirane kože na sterilno goveđe meso: do 3,6 log cfu/cm2 redukcije ukupnog broja bakterija (TVC), do 2,5 log cfu/cm2 Enterobacteriaceae (EC) i do 1,7 log cfu/cm2 generičke E. coli (GEC). Redukcija prenosa TVC je bila značajno vi&scaron;a, a redukcije EC i GEC slične, u odnosu na redukcije nakon tretiranja kože kombinacijom ispiranja-vakumiranja sanitajzerom.<br />U uslovima male komercijalne klanice sa nezadovoljavajućom procesnom praksom (klanje prljavih goveda i neadekvatna higijena procesa klanja i obrade), tretman koža zaklanih goveda 23% rastvorom &scaron;elaka je rezultirao značajnom mikrobnom redukcijom na mesu trupova goveda nakon skidanja kože: 1,7 log cfu/cm2 TVC, 1,4 log cfu/cm2 EC i 1,3 log cfu/cm2 GEC. Redukcija TVC na mesu trupova je bila značajno vi&scaron;a, a redukcije EC i GEC slične, u odnosu na redukcije nakon tretiranja kože ispiranjem-vakumiranjem sanitajzerom.<br />Ova istraživanja su po prvi put pružila naučne dokaze da se tretman kože goveda u cilju imobilizacije mikroflore na dlaci može uspe&scaron;no koristiti u cilju smanjenja kontaminacije mesa trupova tokom procesa skidanja kože, unapređenja finalnog mikrobiolo&scaron;kog statusa mesa i bezbednosti goveđeg mesa uop&scaron;te. Da bi se ostvario puni potencijal ovog novog tretmana u praksi, neophodna su dalja istraživanja u cilju njegove tehničke optimizacije u uslovima industrije mesa.</p> / <p> In this research, a new approach to cattle hide treatments, based on using a natural, food-grade resin, Shellac, to reduce microbial cross-contamination from the hides onto carcass meat, was developed and evaluated. The basis of this treatment is immobilisation of microorganisms on cattle hide&rsquo;s hair and subsequent reduction of their transmissibility from the hair onto carcass meat during dressing of slaughtered cattle.<br /> Under in vitro conditions, treatment of samples of visually clean and dry hides with 23% Shellac-in-ethanol solution reduced sponge-swabbing recoveries of general microflora (TVC) by a factor of 6.6 logs (&gt;1000-fold greater than the 2.9 log reduction observed by ethanol alone), and of generic E. coli (GEC) and Enterobacteriaceae (EC) by factors of at least 2.9 and 4.8 logs, respectively. The reductions of these three groups of microorganisms were superior to those achieved by a sanitizer rinse-vacuum hide treatment. Significantly greater reductions of TVC recoveries from hides were achieved when using higher Shellac concentrations (23.0% and 30.0% rather than 4.8-16.7%) and when Shellac solution temperatures were 20-40&deg;C rather than 50-60&deg;C. Furthermore, the Shellac-based treatment also markedly reduced the E. coli O157 prevalence (3.7-fold reduction) on natural, uninoculated hides, as well as the counts of E. coli O157 on artificially inoculated hides (2.1 log reduction) when compared to corresponding untreated controls.<br /> Under the conditions of a hide-to-meat direct contact laboratory-based model, treatment of hides (of varying visual cleanliness) with the 23% Shellac solution produced significant reductions of microbial transfer from treated hide onto sterile beef: up to 3.6 log10 CFU/cm2 of TVC, up to 2.5 log10 CFU/cm2 of EC and up to 1.7 log10 CFU/cm2 of GEC. TVC reductions of microbial transfer from treated hide onto beef achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ between the two hide treatments.<br /> In a small commercial abattoir with unsatisfactory process practices (slaughtering dirty cattle, inadequate process hygiene), treatment of hides with Shellac produced significant microbial reductions on skinned beef carcasses: 1.7 log10 CFU/cm2, 1.4 log10 CFU/cm2 and 1.3 log10 CFU/cm2 of TVC, EC and GEC, respectively. TVC reductions on skinned beef carcasses achieved by the Shellac hide treatment were superior to those achieved by the comparative sanitizer rinse-vacuum hide treatment, but reductions of EC and GEC did not differ significantly between the two hide treatments.<br /> These investigations produced the first scientific evidence that treatment of cattle hides with aim of immobilising microflora on the hair can be very successfully used to reduce carcass meat contamination during the skinning operation, thus improving the microbiological status of the final beef carcasses as well as the beef safety in general. To achieve the full potential of this new treatment in practice, further research aimed at its further technical optimization under real-life meat industry conditions is necessary.</p>

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-06-30T14:45:00Z No. of bitstreams: 1 IÁNGLIO MÁRCIO TRAVASSOS DUARTE JÁCOME - DISSERTAÇÃO PPGEA 2005..pdf: 24122932 bytes, checksum: 394218ab3657d7c67f9f55e27833d36b (MD5) / Made available in DSpace on 2018-06-30T14:45:00Z (GMT). No. of bitstreams: 1 IÁNGLIO MÁRCIO TRAVASSOS DUARTE JÁCOME - DISSERTAÇÃO PPGEA 2005..pdf: 24122932 bytes, checksum: 394218ab3657d7c67f9f55e27833d36b (MD5) Previous issue date: 2005-03 / O objetivo deste trabalho foi medir os efeitos de diferentes sistemas de acondicionamento ambiental sobre o desempenho de poedeiras comerciais semi pesadas vermelhas nas três fases de criação entre setembro de 2003 a maio de 2004. Foram utilizados dois galpões com acondicionamento térmico diferentes, sendo um com cobertura de telhas de cimento amianto (GTA) e outro com cobertura de telhas cerâmicas (GTC) e avaliados a temperatura do ar, índices de temperatura do globo negro e umidade (ITGU), carga térmica de radiação (CTR), umidade relativa do ar (UR) e níveis de ruído no interior das instalações. O desempenho das poedeiras, foi avaliado pela produção total e pela qualidade dos ovos. A fase experimental foi realizada em galpão de criação para poedeiras comerciais. Os índices ambientais foram medidos diariamente, em intervalos de duas horas, das 8 às 16 horas, nas áreas interna e externa dos galpões experimentais. A análise das médias mostrou que na fase de pinteiro, durante as primeiras semanas de vida, houve falha no aquecimento das pintainhas, com temperaturas atingindo no máximo 31,27°C no interior das instalações, sendo que a partir da 5a semana houve um inverso e as instalações não proporcionaram níveis adequados de conforto com temperaturas elevadas. A fase de recria foi a que apresentou maiores falhas nos níveis de conforto térmico e a fase de postura apresentou níveis adequados de conforto na maior parte dos horários analisados durante a fase experimental em virtude dos altos índices pluviométricos registrados na região nos meses de pesquisa. Os resultados foram analisados estatisticamente por meio do teste t de Tukey ao nível de 1 e 5% de probabilidade, tendo em vista que o mesmo é recomendado para comparação de médias nas condições deste trabalho. Concluiu-se, baseado nos índices térmicos ambientais, que o sistema com telhas cerâmicas apresentou os melhores resultados de Temperatura ambiente, ITGU, CTR e UR, nas fases de recria e postura e baseado nos índices de desempenho produtivo das aves, a produção atingiu média de 90% no GTC e 87,20% no GTA. Em relação à qualidade do ovo houve diferenças estatísticas (P< 0,05) entre as aves mantidas nos diferentes galpões em relação ao peso do ovo e do albúmem, enquanto que as demais variáveis não apresentaram diferenças. / The objective of this work was to measure the effects of different systems of environmental conditions on the performance of red commercial semi-heavy hens in the three creation phases among September of 2003 to May of 2004. Two hangars were used with different thermal packaging, one with asbestos cement tiles covering (GTA) and other with ceramic tiles covering (GTC). The temperature of the air, indexes of temperatura of the black globe and humidity (ITGU), thermal load of radiation (CTR), relative humidity of the air (UR) and noise leveis inside the facilities were evaluated. The hens performance was evaluated by the total production and for the quality of the eggs. The experimental phase was accomplished at creation hangar for commercial hens. The environmental indexes were measured daily, in intervals of two hours, of the 8 to the 16 hours, in the internai and externai áreas of the experimental hangars. The analysis of the averages showed that in the birth phase, during the first weeks of life, there was failings in the heating of the bird, with temperaturas reaching at the most 31,27°C inside the facilities, and starting from to 5th week there was an inverse behavior and the facilities didn"t provide appropriate leveis of comfort with high temperaturas. The phase of rebirth was the one that presented larger flaws in the leveis of thermal comfort and the postura phase presented appropriate leveis of comfort in most of the schedules analyzed during the experimental phase because of the high rain indexes registered in the area in the months of research. The results were analyzed by statistical methods through the test t of Tukey at the levei of 1 and 5% of probability. It was concluded, based on the environmental thermal indexes, that the system with ceramic tiles presented the best room temperature results, ITGU, CTR and UR in the phases of recreation and postura and based on the indexes of productive performance of the birds - the production reached average of 90% in GTC and 87,20% in GTA. In relation to the quality of the eggs, there were statistical differences (P <0,05) among the birds maintained at the different hangars in relation to the weight of the egg and of the egg white, while the other variables didn't present differences.