Orientador : Edison J. Geromel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos e Agricola / Made available in DSpace on 2018-07-15T17:56:22Z (GMT). No. of bitstreams: 1 Netto_FlaviaMaria_M.pdf: 16490409 bytes, checksum: ce51baa4acb2f82fadac0195e8a30739 (MD5) Previous issue date: 1984 / Resumo: O presente trabalho teve como objetivo estudar a conservação do híbrido de tilápia estocado em gelo, sob o aspecto químibo, bioquímico e sensorial.A composição centesimal foi determinada em três diferentes épocas do ano, não apresentando variação sazonal. A tilápia foi classificada como pescado de alto teor protéico e o baixo teor de gordura. A conservação do pescado ao longo da estocagem em gelo foi estudada através de três experimentos. No Experimento I a avaliação foi realizada utilizando-se a escala desenvolvida pela Torry Research Sta-tion, com os seguintes parâmetros: aparência geral, textura ao tato e odor das guelras. Esta escala, desenvolvida para gadídeos, ofereceu dificuldades à equipe sensorial. Para contorná-las, no Experimento II, foi traçado o perfil de deterioração do pescado, e com base nos resultados obtidos, foi desenvolvida uma nova escala, específica para o híbrido de tilápia. No Experimento III, a nova escala foi testada e obteve-se me-lhores resultados para avaliação da deterioração durante a estocagem do que haviam sido obtidas anteriormente com a escala tradicional.Para os três experimentos, além dos testes sensoriais, a conservação em gelo foi acompanhada por determinações químicas (bases ni-trogenadas voláteis, nitrogênio não protéico, pH e reações de Éber). Nenhum dos testes realizados apresentou-se confiável como índice de frescor, embora a reação de Éber para gás sulfídrico tenha indicado o iní-cio da deterioração.As modificações na fração das proteínas sarcoplasmáticas fo-ram acompanhadas durante os experimentos por eletroforese em gel de poliacrilamida. Observaram-se modificações no eletroforegrama nos dife-rentes períodos de estocagem. No entanto, este comportamento não se mostrou de interesse para uma possível utilização como índice de frescor / Abstract: The objective of this project was to study chemical, biochemical and sensory aspects of tilapia hybrids stored in ice. The proximate composition was determined at three different occasion during the year, showing no seasonal variation. Tilapia was classified as a high-protein, low-fat fish. Throughout storage, the preservation of the fish on ice was studied by mean of three experiments. In Experiment I, sensory evaluation was carried out using a scale developed at Torry Research Station, which includes the following parameters: general appearence, texture finger-pressing and odour of the gills. However, it was observed that this scale, developed for fish of the Gadidae family, posed difficulties for the test panel. In order to overcome this, in Experiment II, the deterioration profile of the fish was traced. Based on these results, a new scale was developed, specific for tilapia hibrids. In Experiment III this new scale was tested. Better results was observed for evaluation of tilapia hybrids during sotrage, than those obtained previously whith the traditional scale (Torry). In all three experiments, in addition to sensory analysis, the preservation in ice was followed by chemical determinations (nitro-genous volatile bases, non-protein nitrogen, pH and Eber reaction). None of these tests where shown to be reliable indices of freshness, although the Eber reaction for hidrogen sulphide gas indicated the onset of deterioration. Modifications in the sarcoplasmatic protein fraction during storage were also followed in the three experiments, using polyacrylamide gel electrophoresis. The electrophoregrams were shown to change during ice storage, but this behaviour was not shown to be of the interest as a possible indicator of the degree of freshness / Mestrado / Mestre em Tecnologia de Alimentos

High-pressure (HP) depresses the phase-transition point of water especially in the case of ice-I (down to -21°C at about 210 MPa). This phenomenon has several potential advantages in food processing applications, such as pressure shift freezing (PSF) and HP thawing. However, scientific knowledge available in this area is still relatively limited. The main objectives of this research were to investigate the phase-transition behavior of foods under pressure processing in the context of PSF and HP thawing techniques and to evaluate their impact on product quality. / Distilled water and fresh pork muscle were tested by a HP differential scanning calorimeter (DSC) using isothermal pressure scan (P-scan) and isobaric temperature scan (T-scan). P-scan tests showed that the phase-transition temperature (T) of pork was a function of the weighted-average pressure (P¯1--2): T = -1.17 - 0.102P¯1--2 - 0.00019 P&d1;21-2 (R2 = 0.99) that was much lower than that of pure ice. The phase-change latent heat of pork was estimated by P-scan. T-scan indicated the phase-transition point at a constant pressure, but it showed less accurate than P-scan. The ratio (Rice, %) of ice crystals formed by rapid release of pressure (P) was evaluated using the HP DSC: Rice-water = 0.115P + 0.00013P2 (R2 = 0.96) for water, and Rice-pork = 0.084P + 0.00012P2 (R2 = 0.95) for pork muscle. In the developed method, the pressure-dependent thermal properties of test materials are not required. / A preliminary study on ice-crystal formation was carried out using small gelatin gel samples frozen by conventional air freezing (CAF), liquid immersion freezing (LIF) and PSF at different pressures. The ovoid structure left from ice crystals was evaluated for area, equivalent diameter, roundness and elongation. The diameter (mean +/- S.D.) was 145 +/- 66, 84 +/- 26, 91 +/- 30, 73 +/- 29, and 44 +/- 16 mum for the treatments of CAF, LIF and PSF at 100, 150 and 200 MPa, respectively. Roundness and elongation did not show a clear trend with different freezing tests. Similar experiments using small-size Atlantic salmon (Salmo salar) resulted in the diameter of 110 +/- 41, 17 +/- 8.4, 16 +/- 8.8, 8.2.5 and 5.0 +/- 2.1 mum for CAF, LIF and PSF at 100, 150 and 200 MPa, respectively. The roundness was 0.38 +/- 0.14, 0.55 +/- 0.21, 0.57 +/- 0.18, 0.63 +/- 0.14 and 0.71 +/- 0.14 for the above treatments, respectively. (Abstract shortened by UMI.)

No description available.

Introdução - O pescado é amplamente utilizado para a produção de alimentos à base de matéria-prima de origem animal. Nas últimas décadas, inovações tecnológicas possibilitaram o aumento na comercialização de pescado na forma de filé congelado, tornando o controle de temperatura durante a cadeia de produção essencial para a manutenção da sua qualidade. A importação de pescado, inclusive da Polaca do Alasca, vem crescendo ano a ano, sendo os supermercados e hipermercados, da Região Metropolitana de São Paulo, responsáveis por 49,0 por cento de toda a demanda nacional. Objetivos - Avaliar as condições higienicossanitárias de pescado congelado e embalado exposto à venda em gôndolas de supermercados da Grande São Paulo, de acordo com a legislação vigente. Métodos - A pesquisa foi desenvolvida com base em duas abordagens: estudo de campo e laboratorial. Foram selecionados 30 supermercados de 4 municípios da região da Grande São Paulo para aplicação de checklist de avaliação das condições higienicossanitárias do produto e dos equipamentos de exposição e para a coleta de amostras, no período de 7 a 29 de setembro de 2013. Foram coletadas 30 amostras, sendo cada amostra constituída por 3 embalagens de 1 kg de filé de Polaca do Alasca congelado de uma mesma marca, lote, data de fabricação e validade; representando 3 kg por amostra e totalizando 90 kg de produto analisado. Uma parte das amostras, 30 embalagens de 1 kg, foi acondicionada em caixas isotérmicas com temperatura controlada e encaminhada ao laboratório da Faculdade de Medicina Veterinária e Zootecnia da USP para realização das análises microbiológicas (Staphylococcus coagulase positiva e Salmonella spp). As demais 60 embalagens de 1k foram encaminhadas, sob as mesmas condições, ao laboratório do Instituto de Pesca para realização das análises físico-químicas (pH, N-BVT e N-TMA) e sensoriais (colorimetria e textura). Resultados - As principais não conformidades encontradas no checklist, em ordem decrescente, foram: presença de cristais de gelo (100,0 por cento ) e temperatura abusiva dos produtos acima de -12°C (100,0 por cento ); ausência do carimbo do SIF (83,3 por cento ); falta de veracidade na temperatura indicada no termômetro do equipamento (66,6 por cento ) e presença de restos de alimento no fundo dos equipamentos (50,0 por cento ). As análises físico-químicas para o N-BVT e N-TMA; e, as análises microbiológicas para pesquisa de Salmonella spp em 25 gramas e contagem de Staphylococcus coagulase positiva indicaram 100,0 por cento de conformidade com a legislação vigente. A totalidade das amostras apresentou-se não conforme para o parâmetro pH, com medições que variaram de 6,86 a 8,57. Nas análises sensoriais encontraram-se valores de firmeza do filé de 9,02 a 2,52 N, com uma média de 5,3 ± 1,6 N e a colorimetria indicou que os filés de Polaca do Alasca encontravam-se escurecidos e amarelados. Conclusão - A aplicação do checklist indicou deficiências na manutenção da temperatura e na operação das gôndolas de exposição, não proporcionando as condições ideais para a manutenção do pescado congelado durante o seu armazenamento. Embora os resultados das análises microbiológicas tenham demonstrado que os produtos estivessem próprios para o consumo, as análises físico-químicas, em específico os parâmetros referentes ao pH, não estavam de acordo com os valores determinados pela legislação vigente. / Introduction - Fish products are widely used for food production based on raw material of animal origin. In the last decades, technological innovations enabled a raise in the commercialization of frozen fish fillets that turned the temperature control throughout the food chain into essential for its quality maintenance. The import trade of fish products, amongst them the Walleye Pollock, is increasing year after year, being the supermarkets and hypermarkets of São Paulos Metropolitan Region responsible for 49,0 per cent of all Brazilian imported fish products demand. Objective - To evaluate the hygienic-sanitary conditions of packaged frozen fish exposed for sale in supermarkets of Greater São Paulo in accordance with legal regulations. Methodology - This study was based upon two approaches: case study research and laboratory analysis. It was selected 30 supermarkets of four counties of the Greater São Paulo region for the evaluation of products and equipments hygienic-sanitary conditions by the application of a specific checklist and sample collection, from 7 to 29 September 2013. It was collected 30 samples, which one comprised of 3 - 1 kg packages of Walleye Pollock frozen fillets from the same brand, batch number, manufacturing and expiration date, representing 3 kg by sample and totaling 90 kg of analyzed product. A share of these samples, 30 - 1 kg packages, was accommodated and transported in temperature-controlled isothermal box to the Faculty of Veterinary Medicine and Animal Science of USP laboratory for the microbiological (Coagulase positive Staphylococci and Salmonella spp) analysis. The other 60 - 1kg packages were sent, under the same conditions, to the Fishery Institute for physico-chemical (pH, N-BVT and N-TMA and sensory (colorimetry and texture) analysis. Results - The non-compliance acts more frequently observed in the checklist, in descending order, were: presence of ice crystals (100,0 per cent ) and abusive temperature above - 12°C (100,0 per cent ) of the products, absence of SIF imprint (83,3 per cent ); lack of truthfulness in the temperature indicated on the equipment thermometer (66,6 per cent ) and presence of food remains at the bottom of the equipment (50,0 per cent ). The physico-chemical analysis for N-BVT and N-TMA; and, the microbiological analysis for Salmonella spp/25 g and the coagulase positive Staphylococci counts indicated 100,0 per cent of compliance with legal regulations. The totality of the samples were inadequate for the pH parameter, with measurements ranging from 6,86 to 8,57. The sensory analysis shown values of fillet firmness of 9,02 to 2,52 N, in an average of 5,3 &177; 1,6 N and the colorimetry indicated that the walleye pollock fillets were darkened and yellowish. Conclusion - The checklist results pointed out to deficiencies in controlling the temperature and freezers operations and did not offer the ideal conditions to frozen fishs quality maintenance throughout its storage. Although the microbiological analysis results showed that the frozen fish fillets were appropriate for consumption, the physic-chemical analysis, particularly the pH parameters, were not in accordance with values indicated in the current regulation.

Introdução - O pescado é amplamente utilizado para a produção de alimentos à base de matéria-prima de origem animal. Nas últimas décadas, inovações tecnológicas possibilitaram o aumento na comercialização de pescado na forma de filé congelado, tornando o controle de temperatura durante a cadeia de produção essencial para a manutenção da sua qualidade. A importação de pescado, inclusive da Polaca do Alasca, vem crescendo ano a ano, sendo os supermercados e hipermercados, da Região Metropolitana de São Paulo, responsáveis por 49,0 por cento de toda a demanda nacional. Objetivos - Avaliar as condições higienicossanitárias de pescado congelado e embalado exposto à venda em gôndolas de supermercados da Grande São Paulo, de acordo com a legislação vigente. Métodos - A pesquisa foi desenvolvida com base em duas abordagens: estudo de campo e laboratorial. Foram selecionados 30 supermercados de 4 municípios da região da Grande São Paulo para aplicação de checklist de avaliação das condições higienicossanitárias do produto e dos equipamentos de exposição e para a coleta de amostras, no período de 7 a 29 de setembro de 2013. Foram coletadas 30 amostras, sendo cada amostra constituída por 3 embalagens de 1 kg de filé de Polaca do Alasca congelado de uma mesma marca, lote, data de fabricação e validade; representando 3 kg por amostra e totalizando 90 kg de produto analisado. Uma parte das amostras, 30 embalagens de 1 kg, foi acondicionada em caixas isotérmicas com temperatura controlada e encaminhada ao laboratório da Faculdade de Medicina Veterinária e Zootecnia da USP para realização das análises microbiológicas (Staphylococcus coagulase positiva e Salmonella spp). As demais 60 embalagens de 1k foram encaminhadas, sob as mesmas condições, ao laboratório do Instituto de Pesca para realização das análises físico-químicas (pH, N-BVT e N-TMA) e sensoriais (colorimetria e textura). Resultados - As principais não conformidades encontradas no checklist, em ordem decrescente, foram: presença de cristais de gelo (100,0 por cento ) e temperatura abusiva dos produtos acima de -12°C (100,0 por cento ); ausência do carimbo do SIF (83,3 por cento ); falta de veracidade na temperatura indicada no termômetro do equipamento (66,6 por cento ) e presença de restos de alimento no fundo dos equipamentos (50,0 por cento ). As análises físico-químicas para o N-BVT e N-TMA; e, as análises microbiológicas para pesquisa de Salmonella spp em 25 gramas e contagem de Staphylococcus coagulase positiva indicaram 100,0 por cento de conformidade com a legislação vigente. A totalidade das amostras apresentou-se não conforme para o parâmetro pH, com medições que variaram de 6,86 a 8,57. Nas análises sensoriais encontraram-se valores de firmeza do filé de 9,02 a 2,52 N, com uma média de 5,3 ± 1,6 N e a colorimetria indicou que os filés de Polaca do Alasca encontravam-se escurecidos e amarelados. Conclusão - A aplicação do checklist indicou deficiências na manutenção da temperatura e na operação das gôndolas de exposição, não proporcionando as condições ideais para a manutenção do pescado congelado durante o seu armazenamento. Embora os resultados das análises microbiológicas tenham demonstrado que os produtos estivessem próprios para o consumo, as análises físico-químicas, em específico os parâmetros referentes ao pH, não estavam de acordo com os valores determinados pela legislação vigente. / Introduction - Fish products are widely used for food production based on raw material of animal origin. In the last decades, technological innovations enabled a raise in the commercialization of frozen fish fillets that turned the temperature control throughout the food chain into essential for its quality maintenance. The import trade of fish products, amongst them the Walleye Pollock, is increasing year after year, being the supermarkets and hypermarkets of São Paulos Metropolitan Region responsible for 49,0 per cent of all Brazilian imported fish products demand. Objective - To evaluate the hygienic-sanitary conditions of packaged frozen fish exposed for sale in supermarkets of Greater São Paulo in accordance with legal regulations. Methodology - This study was based upon two approaches: case study research and laboratory analysis. It was selected 30 supermarkets of four counties of the Greater São Paulo region for the evaluation of products and equipments hygienic-sanitary conditions by the application of a specific checklist and sample collection, from 7 to 29 September 2013. It was collected 30 samples, which one comprised of 3 - 1 kg packages of Walleye Pollock frozen fillets from the same brand, batch number, manufacturing and expiration date, representing 3 kg by sample and totaling 90 kg of analyzed product. A share of these samples, 30 - 1 kg packages, was accommodated and transported in temperature-controlled isothermal box to the Faculty of Veterinary Medicine and Animal Science of USP laboratory for the microbiological (Coagulase positive Staphylococci and Salmonella spp) analysis. The other 60 - 1kg packages were sent, under the same conditions, to the Fishery Institute for physico-chemical (pH, N-BVT and N-TMA and sensory (colorimetry and texture) analysis. Results - The non-compliance acts more frequently observed in the checklist, in descending order, were: presence of ice crystals (100,0 per cent ) and abusive temperature above - 12°C (100,0 per cent ) of the products, absence of SIF imprint (83,3 per cent ); lack of truthfulness in the temperature indicated on the equipment thermometer (66,6 per cent ) and presence of food remains at the bottom of the equipment (50,0 per cent ). The physico-chemical analysis for N-BVT and N-TMA; and, the microbiological analysis for Salmonella spp/25 g and the coagulase positive Staphylococci counts indicated 100,0 per cent of compliance with legal regulations. The totality of the samples were inadequate for the pH parameter, with measurements ranging from 6,86 to 8,57. The sensory analysis shown values of fillet firmness of 9,02 to 2,52 N, in an average of 5,3 &177; 1,6 N and the colorimetry indicated that the walleye pollock fillets were darkened and yellowish. Conclusion - The checklist results pointed out to deficiencies in controlling the temperature and freezers operations and did not offer the ideal conditions to frozen fishs quality maintenance throughout its storage. Although the microbiological analysis results showed that the frozen fish fillets were appropriate for consumption, the physic-chemical analysis, particularly the pH parameters, were not in accordance with values indicated in the current regulation.

The consumption of seafood in the United States has increased rapidly in recent years due to high quality protein and health benefits of seafood. Seafood can be a carrier for bacteria normally distributed in the marine environment and, in some cases, can be contaminated by human pathogens. Therefore, there is a potential health risk if seafood is consumed raw or undercooked. However, information regarding prevalence of foodborne pathogens in retail seafood products and the ability of pathogens to survive in the products during refrigerated and frozen storage is limited. The objective of this study was to generate such information for a better understanding of distribution of foodborne pathogens in seafood products and provide data which might be used for risk assessment of foodborne infection associated with seafood consumption. A total of 45 seafood products were collected from local retail stores and analyzed for aerobic plate counts (APC) and psychrotrophic bacterial counts (PBC) as well as presence of foodborne pathogens, including Escherichia coli O157:H7, Salmonella, Listeria monocytogenes, Staphylococcus aureus, Vibrio parahaemolyticus, and Vibrio vulnificus according to procedures described in the U.S. Food and Drug and Administration Bacteriological Analytical Manual (BAM). Presumptive isolates for each foodborne pathogen were further characterized by biochemical reactions using commercial identification kits and confirmed with polymerase chain reaction (PCR) assay. The samples had bacterial populations ranging from 1.90 to 6.11 CFU/g for APC and from 2.00 to 6.78 CFU/g for PBC. According to the microbiological criteria of International Commission on Microbiological Specifications for Foods (ICMSF), all 45 samples were considered acceptable quality (APC < 10⁷ CFU/g, E. coli < 3 MPN/g) with most samples (93.3%) being good quality (APC < 5 × 10⁵ CFU/g, E. coli < 3 MPN/g). No E. coli O157:H7, Salmonella, S. aureus, V. parahaemolyticus, and V. vulnificus was detected in any samples. Two previously frozen shrimp products (4.4%) were confirmed to carry L. monocytogenes. Studies of growth and survival of L. monocytogenes (3 strains), S. aureus (2 strains), and Salmonella (2 serovars) in raw yellowfin tuna meat stored at 5 - 7 °C for 14 days revealed that L. monocytogenes had the ability to multiply in the tuna meat during refrigerated storage while populations of S. aureus and Salmonella were reduced by 1 to 2 log CFU/g after 14 days at 5 - 7 °C. Studies of holding raw yellowfin tuna meat contaminated with L. monocytogenes, S. aureus, and Salmonella at -18 ± 2 °C for 12 weeks observed that all three pathogens, except Salmonella Newport, in tuna samples survived the frozen storage with less than 2- log of reductions in the populations over 12 weeks of storage. No viable cell of Salmonella Newport was detected in samples after 42 days storage at -18 °C. Raw seafood can be a carrier of foodborne pathogens, particularly L. monocytogenes, and many foodborne pathogens can survive in frozen products for several months. Consumption of raw or undercooked seafood products may lead to human infection if the products are contaminated with pathogens. Therefore, sanitation standard operating procedure (SSOP), good manufacturing practice (GMP) and hazards analysis and critical control points (HACCPs) programs shall all be implemented in the seafood industry to prevent seafood products from being contaminated with foodborne pathogens during handling and processing. Moreover, proper storage of raw seafood products and avoiding cross-contamination during handling at the retail levels also helps to minimize risk of human infection associated with ready-to-eat products. / Graduation date: 2013