Orientador: Nelson Jose Beraquet / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-04T02:21:19Z (GMT). No. of bitstreams: 1 Cavenaghi_AngelaDulce_D.pdf: 820135 bytes, checksum: d87ee57cf9506eb8fcb111d97c637bf4 (MD5) Previous issue date: 2005 / Resumo: Face às demandas do mercado é necessário diversificar a elaboração de produtos industrializados à base de carne de frango, particularmente da carne da perna e coxa de frango que tem menor aceitação que o peito. Embutidos fermentados cozidos podem ser elaborados com carne de perna e coxa de frango constituindo-se num novo produto, ainda não disponível no mercado brasileiro. Carne de perna e coxa de frango foi utilizada em substituição às carnes suína e bovina numa formulação padrão de salame, mantendo-se o toucinho, e realizando-se a cocção após o estágio de fermentação quando o pH desejado foi atingido. Foram avaliados os efeitos da adição de dextrose em dois níveis 0,4 e 0,75%, duas misturas de culturas iniciadoras, sendo a cultura 1 (Staphylococcus carnosus e Lactobacillus pentosus) e a cultura 2 (Staphylococcus xylosus e Pediococcus pentosaceus), e adição de gordura suína também em dois níveis 12 e 16%. Essa última variável visa a obtenção de produtos lights e convencionais. O tempo de secagem/maturação foi controlado para obter duas faixas de atividade de água (Aa) no produto final, 0,87-0,88 e 0,90-0,91. O delineamento experimental foi um fatorial completo, totalizando 16 tratamentos efetuados em duplicata. As curvas de queda de pH e Aa foram determinadas a partir de medidas tomadas durante o processamento. Avaliou-se a composição aproximada da massa de embutimento e dos produtos finais. As medidas de L*, a* e b*, força de cisalhamento, nitrito residual, cloretos e acidez lática foram realizadas nos produtos finais e conduziu-se análises sensoriais de aceitação (sabor, firmeza, cor e avaliação global) e descritiva quantitativa (ADQ) (aparência, sabor, textura e aroma). Para a avaliação da segurança microbiológica determinou-se as contagens de coliformes, Salmonella e Staphylococcus coagulase positiva. Os produtos elaborados com 0,4% de dextrose não atingiram pH final abaixo de 5,3 e, portanto seria recomendável a adição de 0,75% de dextrose. O uso da cultura 2 reduziu em cerca de 10 horas o tempo de fermentação, quando comparado à cultura 1. Os produtos elaborados com a cultura 2 e Aa final 0,90-0,91 tiveram o tempo de processamento reduzido em 1 dia em relação aos com Aa 0,87-0,88. Por outro lado, produtos elaborados com a cultura 1 apresentaram aroma mais característico de salame e foram considerados mais suculentos. Os produtos com adição de 12% de gordura poderiam ser classificados como lights de acordo com a legislação brasileira. Para os atributos avaliados todos os tratamentos foram considerados ¿bons¿ com base na análise sensorial de aceitação e na ADQ. Numa segunda fase um produto do tipo light (23,7% de gordura) e outro do tipo convencional (29,5% de gordura) tiveram a sua vida útil determinada sob condições ambientais (temperatura ambiente, seco e fresco). Para este fim, foram conduzidas determinações de pH, Aa, força de cisalhamento, oxidação lipídica e ADQ ao longo do tempo de estocagem. A ADQ mostrou que as características sensoriais dos dois produtos foram praticamente iguais, e na análise de aceitação os dois produtos apresentaram 80% de intenção de compra por parte dos consumidores. A vida útil dos produtos foi estimada em aproximadamente 90 dias uma vez que as primeiras alterações dos atributos sensoriais só ocorreram após 120 dias de estocagem / Abstract: Taking into account the market demands, it is necessary to develop a wider array of industrialized chicken products, with special emphasis on the use of leg and thigh meat since they do not have a consumer acceptance as high as breast meat. Cooked fermented sausages can be made by using chicken leg and thigh meat, creating then a new product not yet available to the Brazilian market. Chicken leg and thigh meat was used to replace pork and beef on a standard salami formulation, maintaining the swine fat cubes and cooking the sausages after the fermentation stage and after they had reached the desired pH level. The effects of two levels of dextrose addition (0.4 and 0.75%) and the development of two different starter cultures (Culture 1 Staphylococcus carnosus and Lactobacillus pentosus, and culture 2 Staphylococcus xylosus and Pediococcus pentosaceus) were evaluated. The salamis also had different added swine fat contents (12 and 16%) in order to result in light e regular products, and the drying/maturation period was controlled in order to obtain two water activity levels (Aw) in the final product (0.87-0.88 and 0.90-0.91). The experimental design was a complete factorial, with a total of 16 treatments in duplicate. The pH and Aw fall curves were determined daily, as were the proximate composition of the initial and final product. The measurements of L*, a* and b* colour values, shear force, residual nitrote, chlorides, and lactic acidity were performed on the final product. Also, sensorial analysis of overall acceptance (taste, firmness, color and overall rating) as well as quantitative descriptive analysis (QDA) (appearance, taste, texture and aroma), were performed on the final product. The microbiological safety of those products was determined through the counting of coliforms, Salmonella, and Staphylococcus aureus. The products made with 0.4% dextrose addition did not reach a pH below 5.3. Therefore the 0.75% level is recommended. The use of culture 2 reduced in 10 hours the fermentation period, comparing to culture 1. The products made using culture 2 and with Aw 0.90-0.91 had the processing time reduced by one day when compared to Aw 0.87-0.88. On the other hand, products made using culture 1 were described as having an aroma more typical of salami and were considered juicier. The products with a 12% fat addition would be classified as light according to the Brazilian legislation. All treatments, considering both the sensorial analyses of overall acceptance and QDA methods, were considered ¿good¿ in terms of the attributes studied. On a second phase, the light product (23.7% fat content) and the regular one (29.5% fat content) had their shelf-lives determined at room temperature. In order to do so were determined the levels of pH and Aw, the shear force, the lipid oxidation, and the QDA throughout the storage period. The QDA showed that the sensory characteristics of the product were similar and presented 80% purchasing intent from consumers. The shelf-life of both product was around 90 days, although the sensory characteristics remained unchanged during 120th day of storage / Doutorado / Tecnologia de Alimentos / Doutor em Tecnologia de Alimentos

Ready to eat (RTE) meat products are subject to recontamination after industrial processing, mainly by Listeria monocytogenes, a pathogenic microorganism that can persist for a long time in the environment. A RTE meat product that is contaminated with L. monocytogenes due to cross contamination during some stage after industrial processing, such as weighing, slicing or wrapping, can be an important causer of disease, due to absence of a kill step before consumption. The objective of this project was to measure the transfer of L. monocytogenes during slicing of cooked ham (cross contamination) at retail, simulating in the laboratory the practices in commercial slicing, and to develop a predictive model capable of describing this transfer. It was observed that in the first slices obtained after the experimental contamination of the slicer, the counts and the transfer rates of L. monocytogenes were higher than in the subsequent slices, and the counting curves presented a long tail as the slices were obtained. The data demonstrate that the slicer may be a relevant source of cross contamination of L. monocytogenes for RTE meat products, regardless of the level of contamination of the slicer. With the data obtained, a new transfer model was proposed called 4p-2se, as it contained four parameters (4p) and two environments (2se), and was independent of the quantification of the pathogen transferred to the slicer. The proposed model was compared to two pathogen transfer models previously described, and the predicted data presented lower RMSE (Root Mean Sum of squared errors) values than the other models. The 4p-2se model was able to satisfactorily predict the pathogen transfer data during slicing of cooked ham, which could assist the food retail establishments and regulatory agencies in the evaluation and control of cross contamination of RTE foods and in the design of proper risk management strategies. / Os produtos derivados da carne que são prontos para consumo estão sujeitos à recontaminação após o processamento industrial, principalmente por Listeria monocytogenes, um microrganismo patogênico capaz de persistir por longo tempo no ambiente. Um produto cárneo pronto para consumo que se contamina com L. monocytogenes devido à contaminação cruzada durante alguma etapa após o processamento industrial, tal como pesagem, fatiamento ou acondicionamento, pode ser um importante causador de enfermidade, pois não há uma etapa de eliminação do patógeno antes do consumo. Este projeto teve por objetivo mensurar a transferência de L. monocytogenes durante o fatiamento de presunto cozido (contaminação cruzada), simulando em laboratório práticas adotadas nos estabelecimentos comerciais de fatiamento de produtos prontos para o consumo, e desenvolver um modelo preditivo capaz de descrever esta transferência. Foi observado que nas primeiras fatias obtidas após a contaminação experimental do fatiador, as contagens e as taxas de transferência de L. monocytogenes eram mais altas que nas subsequentes, observando-se que as curvas de contagem apresentavam uma longa cauda ao longo do fatiamento. Os dados demonstram que o fatiador pode ser uma fonte importante de contaminação cruzada de L. monocytogenes para produtos cárneos prontos para o consumo fatiados, independentemente do nível de contaminação do fatiador. Com os dados obtidos, foi possível sugerir um novo modelo de transferência, denominado 4p-2se, formado por uma equação com apenas quatro parâmetros (4p) e dois ambientes (2se,) sendo esse modelo independente da quantificação do patógeno transferido para o fatiador. O modelo sugerido foi comparado a outros dois modelos de transferência previamente descritos, observando os dados preditos no modelo 4p-2se apresentavam valores de RMSE (Root Mean Sum of squared erros) mais baixos que os demais modelos. O modelo proposto mostrou-se capaz de predizer satisfatoriamente os dados de transferência de patógeno durante o fatiamento de presunto cozido, podendo auxiliar os estabelecimentos comerciais de alimentos e as agências reguladoras na avaliação e controle da contaminação cruzada de alimento prontos para consumo e na concepção de estratégias adequadas de gestão de risco.

This research project was divided into three parts. In the first part, heme, nonheme, and total iron methodologies for meats were evaluated. The accuracy, precision, and specificity of each method were determined by spike recoveries of heme and nonheme iron, and by analysis of National Institute of Science and Technology standard reference materials. The most reliable and practical methods were then used to determine the total, nonheme, and heme iron contents of various meats before and after cooking. The meats analyzed were beef, pork, lamb, chicken, and turkey. The wet-ashing technique was a novel procedure in which nitric acid was used to digest most of the solids followed by peroxy-monosulfuric acid to complete the digestion. Total iron values of the meats were consistent with those previously reported, but the percentage of heme iron in red meats was much greater than commonly assumed, both before and after cooking. In the second part, the distribution of heme and total iron in heat-processed poultry products was investigated using light and dark chicken meat in the form of deep-flied chicken breasts and legs purchased from fast food restaurants and grocery stores in a ready-to-eat condition. Heme and total iron values were 1.7 ± 0.5 and 6.5 ± 2.0 μg Fe/g meat for light chicken meat and 7.6 ± 1.6 and 19.3 ± 2.2 μg Fe/g for dark chicken meat. Percent heme iron values averaged 29 and 40% for light and dark chicken meat, respectively. In the third and final part, an application for the heme and nonheme iron data assembled above was developed to give dieticians an important tool in dietary formulations designed to maintain iron homeostasis. From the data it is evident that cooked light chicken meat, taken from the breast, would provide the lowest quantity of absorbable iron among the meats investigated and that ground beef, highest in heme iron, would provide the greatest quantity of bioavailable iron. Additional research was performed on processed beef products. Cooked ground beef, frankfurters, beef steak, and roast beef were analyzed for heme and total iron. The different beef products contained similar amounts of total iron, 31.4 to 34.2 μg/g, but the heme iron content ranged from 6.2 μg/g in frankfurters to 36.3 μg/g in beef steak. Percent heme iron ranged from 33.0 to 63.8% in all meats. Total iron, heme iron, and percent heme iron varied significantly (P < 0.01) among meats, sources, and preparations. This research was published and has been reproduced in Appendix F.

No / Is it possible to identify cooked, rather than burnt, bone? Mild heating (≤100 °C,1 h) – typical of cooking – does not lead to detectable changes in any biochemical parameter of bone yet measured. If it is only possible to detect charred bone, how is it possible to detect cooking in the archaeological record? In a previous paper (Koon et al., 2003, J. Arch. Sci.), we used a Transmission Electron Microscopy (TEM) based approach to investigate changes in the organization of the bone protein, collagen, as it is heated, using bone from heating experiments and short term burials. The work revealed that mineralized collagen, despite requiring aggressive treatment to gelatinise the protein (e.g. 90 °C, 240+ h), readily accumulates minor damage. We believe that the presence of mineral matrix stabilises the collagen enabling the damage to accumulate, but preventing it from causing immediate gelatinisation. Once the mineral is removed, the damage can be observed using appropriate visualization methods. In this paper the visualization technique was tested in a blind study of bovine bone from the Anglo-Scandinavian site of Coppergate, York. The purpose of the study was to determine if the method could discriminate between bones thought likely, on the basis of zoo-archaeological and spatial evidence, to have been cooked (high meat yield bones from a domestic context) and those which were butchered but unlikely to have been cooked (low yield bones from a butchery site). The results of the TEM analysis identified two clear groups of bones, one set more damaged than the other. This finding was consistent with archaeozoological interpretation, with the exception of one bone from the domestic context, which was not identified as having been cooked.

O ovo tem sido estudado por sua riqueza nutricional, por apresentar interesse industrial, como matéria-prima, e pelo seu elevado conteúdo de colesterol. Ao mesmo tempo, por sua susceptibilidade à contaminação por salmonela, principalmente, é proposta a irradiação ionizante como medida sanitária. O colesterol está sujeito à oxidação, facilitada por vários fatores, entre os quais a radiação ionizante. Os óxidos de colesterol formados, por sua vez, apresentam propriedades biológicas prejudiciais à saúde, relacionadas com a aterogenicidade, citotoxicidade, carcinogenicidade e mutagenicidade, além de outras manifestações. Os objetivos deste trabalho foram avaliar o efeito da radiação ionizante sobre o pH, viscosidade e cor, além da estabilidade oxidativa do colesterol, em ovos crus armazenados e processados. Com o aumento nas doses utilizadas (1, 2 e 3 kGy) houve redução na viscosidade da clara e na cor da gema, além do aumento da oxidação lipídica, medida através das substâncias que reagem ao ácido tiobarbitúrico (TBARS). Parâmetros como umidade, lípides totais e colesterol das gemas não foram influenciados. No caso da umidade e do colesterol, houve alteração significativa pelo armazenamento (30 dias, a 4ºC). O somatório dos óxidos analisados não variou com a irradiação, só individualmente, contudo variaram com o armazenamento. O processamento térmico provocou um aumento significativo das TBARS, mas apesar disso, o somatório dos óxidos não diferiu entre os tratamentos. / The egg have being studied due its nutritional wealth, for show industrial interest as a raw material, e due its higher cholesterol content. At the same time, due its susceptibility to contamination mainly with salmonella, it is being proposed the ionizating radiation as a hygienic measure. Cholesterol is subject to oxidation, that it is facilitated by several factors, among them ionizating radiation. Formed cholesterol oxides, by its turn, show harmful biological properties to human health, as atherogenicity, cytotoxicity, carcinogenicity and mutagenicity, among others. The objectives of this work were evaluate the effect of ionizating radiation over pH, viscosity and color, besides the oxidative stability of cholesterol, in storaged and processed crude eggs. With the increasement of used doses (1, 2 and 3 KGy), there was an reduction in the viscosity of the egg white and in the color yolk egg, besides the increase in lipidic oxidation, measured through tiobarbituric acid-reactive substances (TBARS). Specifications as humidity, total lipids and egg yolk cholesterol were not influenced. In the subject of humidity and of cholesterol, there was an meaningful alteration due storage (30 days in 4ºC). The sum of the analyzed oxides didn\'t variate with the irradiation, only individually, although it did vary with storage. The themical processing caused an meaningful increase of TBARS, but despite this, the oxides sum didn\'t differed between treatments.

A preferência por produtos prontos para consumo pode implicar em aumento do risco de doenças transmitidas por alimentos (DTAs) e uma grande preocupação, nesse caso, é a presença da Listeria monocytogenes. A infecção por essa bactéria apresenta baixa taxa de morbidade, porém alta de mortalidade, representando maior risco para gestantes, idosos, crianças e indivíduos imunodeprimidos. Os produtos considerados de maior risco são aqueles prontos para o consumo, mantidos sob refrigeração e com longa vida útil. Face ao exposto, foi pesquisada a ocorrência de L. monocytogenes em dois grupos de produtos cárneos fatiados: presunto cozido e salame. Cento e trinta amostras de cada tipo de produto, adquiridas no comércio varejista do Município de São Paulo, foram submetidas a análises laboratoriais. Tais análises foram conduzidas em dois momentos: no terço inicial e no final de vida útil dos produtos. Nos casos de positividade, foram realizadas a quantificação e a sorotipagem da bactéria em cada um dos produtos, a fim de avaliar se os resultados obtidos poderiam oferecer risco à saúde. O salame apresentou prevalência significativamente maior para a L. monocytogenes, 6,2 por cento (8/130), enquanto no presunto a prevalência foi de 0,8 por cento (1/130). As contagens nas amostras de salame apresentaram valores entre <10 a 1900 UFC/g. Os sorotipos identificados, considerando os dois tipos de produtos, apresentaram as seguintes freqüências: 4b= 37,5 por cento (3/8), 1/2b= 25 por cento (2/8), 3b= 25 por cento (2/8) e 1/2c= 12,5 por cento (1/8). Os resultados encontrados permitem inferir que, para os produtos analisados, o risco de listeriose decorrente do consumo de salame é maior do que o associado ao consumo de presunto cozido / The preference for ready-to-eat products can raise the risk of diseases transmitted by food and in this case there is a main concern about the presence of Listeria monocytogenes. The infection caused by these bacteria presents low morbidity but high mortality rate, representing higher risk to pregnants, elderly, children and immunodepressed people. Products considered to have higher risk are the ready-to-eat kept under refrigeration and with longer shelf life. Considering this, it has been searched the occurrence of L. monocytogenes in two groups of sliced meat: cooked jam and salami. There were submitted to laboratorial analyses, to identification of L. monocytogenes, 130 samples of each product, acquired from São Paulo retailing market. Analyses were conducted in two times, in the starting third part life of product and in the end of shelf live. For the positive cases it was realized quantification and serotype from this bacterium, in order to evaluate if found results can offer risk to health. Salami has presented occurrence significantly higher for L. monocytogenes, 6.2 per cent (8/130), while cooked jam has presented 0.8 per cent (1/130). Counts of salami have shown results from <10 to 1900 CFU/g. Identified serotypes, considering both types of products, presented the following frequencies: 4b= 37,5 per cent (3/8), 1/2b= 25 per cent (2/8), 3b= 25 per cent (2/8) e 1/2c= 12,5 per cent (1/8). Presented results allow us to infer, to the tested products, that the risk of listeriosis from consuming salami is higher than the risk associate to consuming cooked jam

<p>Osnovni zadatak ove doktorske disertacije je bio da se ispita<br />uticaj dodatka odabranih etarskih ulja izolovanih iz začinskog<br />i lekovitog bilja (kima, kleke i žalfije) na kvalitet fino<br />usitnjenih barenih i fermentisanih suvih kobasica. Fino<br />usitnjene barene kobasice proizvedene su sa dodatkom<br />etarskih ulja kima, kleke i žalfije u količinama od 0,1, 0,5, 1,0,<br />2,0 i 5,0 &mu;l/g, kao i bez dodatka etarskih ulja (kontrola), dok<br />su fermentisane suve kobasice proizvedene sa dodatkom<br />etarskih ulja kima, kleke i žalfije u količinama od 0,01, 0,05 i<br />0,10 &mu;l/g, kao i bez dodatka etarskih ulja (kontrola). Dodatno,<br />odlučeno je da se ispita i mogućnost delimične ili potpune<br />zamene nitrita sa ovim uljima i to na fermentisanim suvim<br />kobasica koje su proizvedene sa tri različita sadržaja nitrita (0,<br />75 i 150 mg/kg) i dva različita sadržaja masti (15 i 25%) i čiji<br />je kvalitet i bezbednost praćen tokom 225 dana čuvanja.<br />Kvalitet fino usitnjenih barenih i fermentisanih suvih kobasica<br />ispitan je određivanjem i analizom fizičkih [vrednost pH, boja<br />&ndash; instrumentalno (L*, a* i b* vrednosti)], hemijskih [TBARS<br />vrednost, antiradikalska aktivnost prema DPPH radikalu (IC₅₀<br />vrednost), sadržaj ukupnih fenola (samo kod fino usitnjenih<br />barenih kobasica)], mikrobiolo&scaron;kih [ukupan broj aerobnih<br />mezofilnih bakterija, ukupan broj aerobnih mezofilnih<br />sporogenih bakterija, ukupan broj bakterija mlečne kiseline<br />(samo kod fermentisanih suvih kobasica), ukupan broj<br />lipolitičkih bakterija (samo kod fermentisanih suvih kobasica),<br />ukupan broj Enterobacteriaceae, ukupan broj Escherichia<br />coli, ukupan broj sulfitoredukujućih klostridija, Listeria spp.<br />(uključujući i Listeria monocytogenes) (samo kod<br />fermentisanih suvih kobasica), ukupan broj kvasaca i plesni] i<br />senzorskih [boja, miris (samo kod fermentisanih suvih<br />kobasica), ukusnosti] parametara kvaliteta.<br />Kod fino usitnjenih barenih kobasica koje su proizvedene sa<br />dodatkom etarskih ulja kima, kleke ili žalfije, u poređenju sa<br />fino usitnjenim barenim kobasicama koje su proizvedene bez<br />dodatka etarskog ulja, nezavisno od dodate koncentracije etarskih ulja, utvrđeno je sledeće: smanjenje svetloće (L*<br />vrednosti) &ndash; utvrđena je tamnija boja, povećanje udela crvene<br />boje (a* vrednosti), smanjenje udela žute boje (b* vrednosti),<br />smanjenje TBARS vrednosti, smanjenje IC₅₀ vrednosti,<br />povećanje sadržaja ukupnih fenola, smanjenje ukupnog broja<br />aerobnih mezofilnih bakterija, smanjenje ukupnog broja<br />aerobnih mezofilnih sporogenih bakterija, senzorski tamnija<br />boja i senzorski veći intenzitet ukusnosti, s tim da se sa<br />povećanjem koncentracija etarskih ulja efekat smanjenja<br />TBARS vrednosti, smanjenja IC₅₀ vrednosti, povećanja<br />sadržaja ukupnih fenola, smanjenja ukupnog broja aerobnih<br />mezofilnih bakterija, smanjenja ukupnog broja aerobnih<br />mezofilnih sporogenih bakterija i povećanja intenziteta<br />ukusnosti jo&scaron; vi&scaron;e ispoljava.<br />Kod fermentisanih suvih kobasica koje su proizvedene sa<br />dodatkom etarskih ulja kima, kleke ili žalfije, u poređenju sa<br />fermentisanim suvim kobasicama koje su proizvedene bez<br />dodatka etarskog ulja, nezavisno od dodate koncentracije<br />etarskih ulja, utvrđeno je sledeće: povećanje vrednosti pH,<br />smanjenje TBARS vrednosti, senzorski tamnija boja,<br />senzorski veći intenzitet mirisa i senzorski veći intenzitet<br />ukusnosti, s tim da se sa povećanjem koncentracija etarskih<br />ulja efekat smanjenja TBARS vrednosti, povećanja intenziteta<br />mirisa i povećanja intenziteta ukusnosti jo&scaron; vi&scaron;e ispoljava.<br />Kod fermentisanih suvih kobasica koje su proizvedene sa<br />dodatkom nitrita (75 i 150 mg/kg), u poređenju sa<br />fermentisanim suvim kobasicama koje su proizvedene bez<br />dodatka nitrita, utvrđeno je sledeće: veće vrednosti pH, manje<br />svetloće (L* vrednosti) &ndash; utvrđena je tamnija boja, &scaron;to je<br />potvrđeno i senzorski &ndash; rangiranjem, veći udeli žute boje (b*<br />vrednosti), manje TBARS vrednosti, veće IC₅₀ vrednosti,<br />manji ukupan broj bakterija mlečne kiseline (samo kod<br />fermentisanih suvih kobasica koje su proizvedene sa<br />dodatkom nitrita od 150 mg/kg), manje senzorske ocene za<br />razliku u boji i veće senzorske ocene za razliku u mirisu, s tim<br />da je kod fermentisanih suvih kobasica koje su proizvedene sa<br />dodatkom nitrita od 150 mg/kg, u poređenju sa fermentisanim<br />suvim kobasicama koje su proizvedene sa dodatkom nitrita od<br />75 mg/kg, utvrđeno sledeće: veći udeo žute boje (b* vrednost)<br />i manja senzorska ocena za razliku u boji.<br />Kod fermentisanih suvih kobasica koje su proizvedene sa<br />15% masti, u poređenju sa fermentisanim suvim kobasicama<br />koje su proizvedene sa 25% masti, utvrđeno je sledeće: veća vrednost pH, manja svetloća (L* vrednost) &ndash; utvrđena je<br />tamnija boja, veći udeo crvene boje (a* vrednost), veći udeo<br />žute boje (b* vrednost), manja IC₅₀ vrednost, veći ukupan broj<br />aerobnih mezofilnih bakterija i manja senzorska ocena za<br />razliku u boji.<br />U toku čuvanja fermentisanih suvih kobasica (od neposredno<br />nakon proizvodnje do 225 dana) utvrđeno je sledeće:<br />povećanje vrednosti pH, smanjenje svetloće (L* vrednosti) &ndash;<br />utvrđena je tamnija boja, povećanje udela crvene boje (a*<br />vrednosti), povećanje udela žute boje (b* vrednosti),<br />povećanje TBARS vrednosti, povećanje IC₅₀ vrednosti,<br />povećanje ukupnog broja aerobnih mezofilnih bakterija,<br />smanjenje ukupnog broja bakterija mlečne kiseline i<br />povećanje senzorskih ocena za razliku u boji, uz nekoliko<br />izuzetaka koji bitnije ne odstupaju od utvrđenog trenda.</p> / <p>The main aim of this doctoral dissertation is to examine the<br />influence of the addition of selected essential oils isolated<br />from spices and medicinal herbs (caraway, juniper, and sage)<br />on the quality of finely comminuted cooked and dry<br />fermented sausages. Finely comminuted cooked sausages<br />were produced with the addition of essential oils of caraway,<br />juniper, and sage in the respective amounts of 0.1, 0.5, 1.0,<br />2.0, and 5.0 &mu;l/g, as well as without the addition of essential<br />oils (control group), while dry fermented sausages were<br />produced with the addition of essential oils of caraway,<br />juniper, and sage in the respective amounts of 0.01, 0.05, and<br />0.10 &mu;l/g, as well as without the addition of essential oils<br />(control group). In addition, it was decided to examine the<br />possibility of partial or complete replacement of nitrite<br />contents with these oils on dry fermented sausages made with<br />three different levels of nitrite contents (0, 75, and 150 mg/kg)<br />and two different fat contents (15 and 25%), whose quality<br />and safety were monitored during 225 days of storage. The<br />quality of finely comminuted cooked and dry fermented<br />sausages was tested by determining and analysing physical<br />[pH value, colour &ndash; instrumental (L*, a*, and b* values)],<br />chemical [TBARS value, antiradical activity against the<br />DPPH radical (IC50 value), total phenolic content (only for<br />finely comminuted cooked sausages)], microbiological [the<br />total number of aerobic mesophilic bacteria, the total number<br />of aerobic mesophilic sporogenic bacteria, the total number of<br />lactic acid bacteria (only for dry fermented sausages), the<br />total number of lipolytic bacteria (only for dry fermented<br />sausages), the total number of Enterobacteriaceae, the total<br />number of Escherichia coli, the total number of sulphitereducing<br />clostridia, total number of Listeria spp. (including<br />Listeria monocytogenes) (only for dry fermented sausages),<br />the total number of yeasts and moulds] and sensory [colour,<br />odour (only for dry fermented sausages), flavour] quality<br />parametres. For finely comminuted cooked sausages produced with the<br />addition of essential oils of caraway, juniper, or sage, in<br />comparison with finely comminuted cooked sausages<br />produced without the addition of essential oils, independently<br />of the added concentrations of essential oils, the following<br />was determined: a decrease in lightness (L* values) &ndash; a darker<br />colour was determined, an increase in redness (a* values), the<br />decrease in yellowness (b* values), the reduction of TBARS<br />values, a reduction of the IC50 values, an increase of total<br />phenolic content, a reduction of the total number of aerobic<br />mesophilic bacteria, a reduction of the total number of aerobic<br />mesophilic sporogenic bacteria, a sensory darker colour, and a<br />sensory higher intensity of flavour, with an increase in the<br />concentrations of the essential oils resulting in the even more<br />pronounced effect of decreasing the TBARS values, of<br />decreasing the IC50 values, of increasing the total phenolic<br />content, of decreasing the total number of aerobic mesophilic<br />bacteria, of decreasing the total number of aerobic mesophilic<br />sporogenic bacteria, and of increasing the intensity of flavour.<br />In the case of dry fermented sausages produced with the<br />addition of essential oils of caraway, juniper, or sage, in<br />comparison with dry fermented sausages produced without<br />the addition of essential oil, independently of the added<br />concentrations of essential oils, the following was<br />determined: an increase in pH values, a reduction of TBARS<br />values, a sensory darker colour, a sensory higher intensity of<br />odour, and a sensory higher intensity of flavour, with an<br />increase in the concentrations of the essential oils resulting in<br />the even more pronounced effect of decreasing the TBARS<br />values, of increasing the intensity of odour, and of increasing<br />the intensity of flavour.<br />For dry fermented sausages produced with the addition of<br />nitrite (75 and 150 mg/kg), in comparison with dry fermented<br />sausages produced without the addition of nitrite, the<br />following was determined: higher values of pH, lower<br />lightness (L* values) &ndash; a darker colour was determined, which<br />was also confirmed by sensory analysis &ndash; by ranking, higher<br />yellowness (b* values), lower TBARS values, higher IC50<br />values, lower total number of lactic acid bacteria (only for dry<br />fermented sausages produced with the addition of nitrite in<br />the amount of 150 mg /kg), lower sensory scores for colour<br />difference and higher sensory scores for the difference in<br />odour, with a higher yellowness (b* value) and a lower sensory score for colour difference determined in dry<br />fermented sausages produced with the addition of nitrite in<br />the amount of 150 mg/kg, in comparison with dry fermented<br />sausages produced with the addition of nitrite in an amount of<br />75 mg/kg.<br />In the case of dry fermented sausages produced with 15% fat,<br />compared to dry fermented sausages produced with 25% fat,<br />the following was determined: a higher pH value, lower<br />lightness (L* value) &ndash; a darker colour was determined, a<br />higher redness (a* value), a higher yellowness (b* value), a<br />lower IC50 value, a higher total number of aerobic mesophilic<br />bacteria, and a lower sensory score for colour difference.<br />During storage of dry fermented sausages (from the moment<br />of production to 225 days), the following was determined: an<br />increase in pH values, a decrease in lightness (L* values) &ndash; a<br />darker colour was determined, an increase in redness (a*<br />values), an increase in yellowness (b* values), an increase in<br />TBARS values, an increase in IC50 values, an increase in total<br />number of aerobic mesophilic bacteria, a decrease in total<br />number of lactic acid bacteria, and an increase of sensory<br />scores for colour difference, with several exceptions that do<br />not differ greatly from the established trend.</p>

O presunto cozido é um dos embutidos cárneos mais consumidos no Brasil, sendo também um dos mais sensíveis à deterioração por bactérias ácido láticas (BAL) e a contaminação por Listeria monocytogenes. O objetivo deste trabalho foi avaliar a atividade antimicrobiana da nisina (Nisaplin®) aplicada em presunto cozido, a fim de controlar L. monocytogenes e BAL. Para tanto, presuntos cozidos foram preparados e fatiados individualmente pelas empresas DuPont e Marsul. No ensaio 1, o presunto foi injetado com salmoura contendo 12,5 mg de nisina por kg (dosagem aprovada no Brasil para queijos fundidos). O potencial bioconservante da nisina foi avaliado contaminando artificialmente as fatias do presunto com um pool composto por 5 cepas de L. monocytogenes. Os resultados do ensaio 1 demonstraram que o tratamento com nisina não teve efeito significativo sobre a população de L. monocytogenes. Já as BAL foram inibidas por 2 dias. No ensaio 2, a adição da nisina na mesma dosagem foi feita no tambleamento, inibindo a população de L. monocytogenes por 6 dias e BAL por 10 dias Em vista dos resultados obtidos nos 2 primeiros ensaios foi determinada a concentração mínima bactericida (CMB) do pool e dos isolados de L. monocytogenes, a fim de verificar a sensibilidade das cepas individualmente e em conjunto e o efeito da nisina sem a matriz cárnea. Além disso, também foi avaliado o efeito sinérgico ou antagônico da salmoura sobre a ação bactericida da nisina. Pôde-se constatar que as diferentes cepas de L. monocytogenes demonstraram perfis de sensibilidade diferentes e que o pool de cepas foi menos sensível ao efeito da nisina. Os resultados obtidos conduziram a avaliação de dosagem maior de nisina no presunto cozido. No ensaio 3, 32 mg/kg de nisina foram adicionadas a salmoura do presunto cozido e testados contra o pool de L. monocytogenes e a cepa ATCC 7644, separadamente. Os resultados demonstraram que a nova dosagem de nisina inibiu significativamente a multiplicação do pool de L. monocytogenes e da cepa ATCC 7644, durante 10 dias, sugerindo ser uma barreira efetiva no controle de L. monocytogenes em presunto cozido. / Precooked ham is one of the most consumed meats in Brazil. It is also one of the most sensitive to spoilage by lactic acid bacteria (LAB) and contamination by Listeria monocytogenes. The objective of this study is to evaluate the antimicrobial activity of Nisin (Nisaplin®) when applied to precooked ham, in order to control the growth of L. monocytogenes and LAB. For the purposes of this study, the precooked ham prepared and sliced individually by the DuPont and Marsul company was used. For trial 1, brine containing 12.5 mg of nisin was injected per kg of ham (dosage approved in Brazil for processed cheese). The biopreservative potential of nisin was evaluated by artificially contaminating slices of control and test ham with a pool of 5 different strains of L. monocytogenes. The results of this first trial showed that treatment with this amount of nisin had no significant effect on the growth of the L. monocytogenes population. However, the LAB population was indeed inhibited by 2 days. In trial number 2, the addition of nisin to the same amount of precooked ham by tumbling inhibited the growth of the L. monocytogenes population by 6 days and of the LAB population by 10 days. In light of the results obtained in these first 2 trials, the minimum bactericidal concentration (MBC) pool and L. monocytogenes isolates were determined in order to verify the sensitivity of the strains individually and together as well as the effects of nisin without the meat matrix Additionally, the synergistic or antagonistic effects of brine on the antimicrobial properties of nisin were also evaluated. Results suggest that different strains of L. monocytogenes have different sensitivity profiles and that the pool of strains was less sensitive to the effects of the nisin. These results prompted an increase in the dosage of nisin added to the precooked ham in trial number 3. In this trial, 32mg/kg of nisin was added to the brine of the precooked ham and tested against the L. monocytogenes pool and ATCC 7644 strain, separately. Results demonstrated that this increase in amount of nisin significantly reduced the growth of the L. monocytogenes pool and of the ATCC strain for 10 days. This suggests that nisin can be an effective barrier against the growth of L. monocytogenes in precooked ham.

A preferência por produtos prontos para consumo pode implicar em aumento do risco de doenças transmitidas por alimentos (DTAs) e uma grande preocupação, nesse caso, é a presença da Listeria monocytogenes. A infecção por essa bactéria apresenta baixa taxa de morbidade, porém alta de mortalidade, representando maior risco para gestantes, idosos, crianças e indivíduos imunodeprimidos. Os produtos considerados de maior risco são aqueles prontos para o consumo, mantidos sob refrigeração e com longa vida útil. Face ao exposto, foi pesquisada a ocorrência de L. monocytogenes em dois grupos de produtos cárneos fatiados: presunto cozido e salame. Cento e trinta amostras de cada tipo de produto, adquiridas no comércio varejista do Município de São Paulo, foram submetidas a análises laboratoriais. Tais análises foram conduzidas em dois momentos: no terço inicial e no final de vida útil dos produtos. Nos casos de positividade, foram realizadas a quantificação e a sorotipagem da bactéria em cada um dos produtos, a fim de avaliar se os resultados obtidos poderiam oferecer risco à saúde. O salame apresentou prevalência significativamente maior para a L. monocytogenes, 6,2 por cento (8/130), enquanto no presunto a prevalência foi de 0,8 por cento (1/130). As contagens nas amostras de salame apresentaram valores entre <10 a 1900 UFC/g. Os sorotipos identificados, considerando os dois tipos de produtos, apresentaram as seguintes freqüências: 4b= 37,5 por cento (3/8), 1/2b= 25 por cento (2/8), 3b= 25 por cento (2/8) e 1/2c= 12,5 por cento (1/8). Os resultados encontrados permitem inferir que, para os produtos analisados, o risco de listeriose decorrente do consumo de salame é maior do que o associado ao consumo de presunto cozido / The preference for ready-to-eat products can raise the risk of diseases transmitted by food and in this case there is a main concern about the presence of Listeria monocytogenes. The infection caused by these bacteria presents low morbidity but high mortality rate, representing higher risk to pregnants, elderly, children and immunodepressed people. Products considered to have higher risk are the ready-to-eat kept under refrigeration and with longer shelf life. Considering this, it has been searched the occurrence of L. monocytogenes in two groups of sliced meat: cooked jam and salami. There were submitted to laboratorial analyses, to identification of L. monocytogenes, 130 samples of each product, acquired from São Paulo retailing market. Analyses were conducted in two times, in the starting third part life of product and in the end of shelf live. For the positive cases it was realized quantification and serotype from this bacterium, in order to evaluate if found results can offer risk to health. Salami has presented occurrence significantly higher for L. monocytogenes, 6.2 per cent (8/130), while cooked jam has presented 0.8 per cent (1/130). Counts of salami have shown results from <10 to 1900 CFU/g. Identified serotypes, considering both types of products, presented the following frequencies: 4b= 37,5 per cent (3/8), 1/2b= 25 per cent (2/8), 3b= 25 per cent (2/8) e 1/2c= 12,5 per cent (1/8). Presented results allow us to infer, to the tested products, that the risk of listeriosis from consuming salami is higher than the risk associate to consuming cooked jam

Heating milk to high temperatures such as 140 ºC, as used in ultra high temperature (UHT) processing, causes physical and chemical changes in the milk. The production of a cooked flavour is a major change which reduces consumer acceptance of the UHT milk. It has been correlated with the formation of volatile sulphur compounds (VSCs) that result from milk proteins, principally the whey proteins β-lactoglobulin, containing the the sulphur amino acids cystine, cysteine and methionine. The VSCs in milk, whose concentrations are in the parts per billion to parts per million range, are highly reactive, easily oxidised, and sensitive to heat during thermal processing and analysis; this makes them a challenge to analyse. A sensitive method based on gas chromatography with pulsed flame photometric detection coupled with headspace sampling by solid phase microextraction (SPME/GC/PFPD) was developed to detect these compounds in commercial UHT milk and to investigate their production and disappearance during heating and storage. The SPME/GC/PFPD procedure was optimised using different extraction time (15 min, 30 min, & 60 min) – temperature (30 oC, 45 oC & 60 oC) combinations with CAR/PDMS fibre to obtain maximum sensitivity. A short extraction time (15 min) at low temperature (30 oC) was chosen to provide high sensitivity for detecting all VSCs in UHT milk without introducing artefactual VSCs. The extraction method and GC run time (16 min) make this method simple and fast. Nine VSCs were detected in commercial indirectly processed UHT milk, skim and whole. These are hydrogen sulphide (H2S), carbonyl sulphide (COS), methanethiol (MeSH), dimethyl sulphide (DMS), carbon disulphide (CS2), dimethyl disulphide (DMDS), dimethyl sulphoxide (DMSO), dimethyl sulphone (Me2SO2) and dimethyl trisulphide (DMTS). An additional unknown compound was detected but could not be identified by GC/MS because its concentration was below the detection limit of the MS detector. The concentrations of H2S, DMS and DMTS were higher than their threshold values indicating their importance in milk flavour, especially cooked flavour. Several attempts have been made to reduce the cooked flavour in UHT milk. In the current research, the use of hydrogen peroxide (H2O2) to oxidise the VSCs and thereby reduce cooked flavour was investigated. H2O2 is used as a milk preservative and is generally recognised as safe (GRAS) in USA. Several concentrations of H2O2 (0.001%, 0.005%, 0.01%, 0.02% & 0.03%) were added to milk to assess its effects on VSCs and on whey proteins denaturation in UHT milk. H2O2 effectively reduced the concentration of all VSCs, except DMDS which was increased, presumably by oxidation of MeSH. H2S was completely oxidised or reduced below its threshold value. Low concentrations of H2O2 (0.001% & 0.005%) had no effect on, or decreased, the extent of denaturation of β-lactoglobulin when added after or before processing, respectively. Some UHT plants use severe heating conditions, leading to high levels of denaturation of whey proteins, particularly β-Lg, the main source of the VSCs in milk. Correlations between heat severity, β-Lg denaturation and individual VSC generation were investigated in milk batch-heated at 80 oC and 90 oC, and UHT milk processed at 120-150 oC. In accordance with previous reports, β-Lg was more heat-sensitive than α-La. Only five VSCs were detected. The concentrations of H2S and MeSH correlated well with denaturation of β-Lg and α-La. DMS concentration correlated well with β-Lg in UHT milk but not in the batch-heated milk. CS2 did not show a good correlation with heat intensity and appeared to plateau out after a certain level of heating. Conversely, COS and MeSH seemed to require a certain minimum amount of heat before generation commenced; this corresponded to denaturation of β-Lg above 49% and 89% respectively at 80 oC. The higher concentrations of DMS and H2S in UHT milk compared with batch-heated samples having similar degrees of denaturation suggested other possible sources for their production and the importance of the heat severity in generating them. For example, at high heat intensity, S-methylmethionine and thiamine could be sources of DMS and H2S respectively. Furthermore, in whole milk as used in this work, milk fat globule membrane proteins are another source of VSCs. The outcome of this study will help UHT manufacturers to understand the production and disappearance of the VSCs in commercial UHT milk and how to adjust the processing conditions to avoid generation of cooked flavour. Additionally, the promising results of using low concentrations of H2O2 to oxidise the VSCs will provide the industry with another means of reducing cooked flavour. Before H2O2 use is implemented in UHT processing, future studies are required to evaluate all of its effects, including sporicidal effects. Overall, this study makes a contribution to finding a solution to the cooked flavour problem in UHT milk, thereby increasing market share of this milk in countries such as Australia, the UK and North America where cooked flavour is the main barrier to its consumer acceptance.