Добірка наукової літератури з теми "Post harvest contamination"

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Статті в журналах з теми "Post harvest contamination"

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Waliyar, F., M. Osiru, B. R. Ntare, K. Vijay Krishna Kumar, H. Sudini, A. Traore, and B. Diarra. "Post-harvest management of aflatoxin contamination in groundnut." World Mycotoxin Journal 8, no. 2 (January 1, 2015): 245–52. http://dx.doi.org/10.3920/wmj2014.1766.

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Анотація:
Aflatoxin contamination in groundnut by Aspergillus section Flavi is a major pre- and post-harvest problem causing kernel-quality loss. Post-harvest aflatoxin contamination is caused initially by infestation of aflatoxigenic strains at the pre-harvest stage, resulting in reduced kernel quality after harvest. Improper handling of pods and storage methods after harvest lead to high moisture and ambient temperatures, directly causing aflatoxin contamination. In this review, we report the extent of post-harvest contamination along the groundnut value chain in the Kolokani, Kayes, and Kita districts of Mali in West Africa. Groundnut kernels and paste samples were collected from retailers in selected markets from December 2010 to June 2011, and aflatoxin B1 (AFB1) content was estimated. Aflatoxin was significantly higher in groundnut paste than in kernels. Kolokani recorded the highest toxin levels in both kernels and groundnut paste compared with the other districts. Overall, AFB1 levels in kernels and paste increased during storage at the market level in the three districts and were above permissible levels (≯20 μg/kg). The effect of weather factors on post-harvest contamination and the reasons for aflatoxin build-up in Mali are discussed. This paper also highlights different management tools for reducing post-harvest aflatoxin contamination, such as post-harvest grain handling, post-harvest machinery, physical separation, storage methods and conditions, disinfestation, detoxification, inactivation, filtration, binding agents, and antifungal compounds. Post-harvest management options and enhanced use of good agricultural practices for mitigating this problem in Mali are also presented.
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Ndemera, M., S. Landschoot, M. De Boevre, L. K. Nyanga, and S. De Saeger. "Effect of agronomic practices and weather conditions on mycotoxins in maize: a case study of subsistence farming households in Zimbabwe." World Mycotoxin Journal 11, no. 3 (September 18, 2018): 421–36. http://dx.doi.org/10.3920/wmj2017.2227.

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Maize is susceptible to many mycotoxigenic fungi and mycotoxins, being prone to Fusarium spp. infection and subsequent mycotoxin contamination. Fumonisin B1 (FB1) is the predominant mycotoxin in Zimbabwean subsistence-grown maize and results of mycotoxin analyses indicated FB1 to be significantly higher compared to other mycotoxins. To fully elucidate maize agronomic practices influencing FB1 contamination of maize produced by Zimbabwean subsistence farming populations, an investigative field survey was conducted in the selected provinces of Mashonaland West and Manicaland. Agronomic data and associated climatic data were collected during the 2014/2015 agricultural season. A total of 158 maize samples were collected from households’ harvest, three months and six months post-harvest. Analysis and quantification of mycotoxin contamination in the maize samples was performed using a validated multi-mycotoxin analysis method with a scope of 23 mycotoxins. Maize was mainly contaminated by FB1. There was low mycotoxin co-occurrence in Zimbabwean maize, which was typically of Fusarium toxins. FB1 occurred in 23, 47 and 47% of samples at harvest, three and six months post-harvest, respectively. The corresponding means of positive samples were 609, 597 and 289 μg/kg, respectively. Regarding fumonisins, the choice of seed and fertiliser application were significant in modulating FB1 contamination. There was no significant difference in mean FB1 contamination during post-harvest maize storage. Daily temperatures were key factors influencing FB1 incidence and levels. High temperatures were associated with high FB1 contamination particularly at the flowering stage of maize. Rainfall was positively correlated with FB1 contamination. Good agricultural practices attributed to low FB1 contamination in maize pre-harvest. Post-harvest practices such as preserving seed integrity by preventing pest infestation using grain protection chemicals are important in achieving lower mycotoxin contamination and in particular, FB1, in maize grain.
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Chimbaza, M., H. Kankwamba, A. M. Mwangwela, and W. Kamthunzi. "Post-harvest groundnut aflatoxin management among smallholder farmers in Malawi." World Mycotoxin Journal 13, no. 1 (February 6, 2020): 37–43. http://dx.doi.org/10.3920/wmj2018.2409.

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Анотація:
Aflatoxin contamination in groundnut production negatively affects health and trade outcomes. Aflatoxin contamination can occur at any stage along the groundnut value chain. However, the stage immediately after harvest has proven to be the most critical stage in aflatoxin management. This study presents knowledge, perceptions and practices in aflatoxin management during groundnut drying and storage among smallholder farmers in Malawi. Using probability proportionate to size random sampling techniques, the study sampled 150 smallholder farmers from three districts in the Central Region of Malawi namely Lilongwe, Mchinji and Kasungu. Descriptive analysis of results indicates that 90% of farmers harvest groundnuts at the right maturity. Results also showed that 59% farmers prefer drying groundnuts inverted in circular patches while 70% store groundnuts in polyethylene sacks on racks. Further, the study found that 97% of the farmers in the sample are aware of aflatoxin contamination but only 28% were able to identify the effects of aflatoxin contamination. These findings have implications in the design of postharvest intervention strategies on management and control of aflatoxin in groundnuts.
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Pandey, Manish K., Rakesh Kumar, Arun K. Pandey, Pooja Soni, Sunil S. Gangurde, Hari K. Sudini, Jake C. Fountain, et al. "Mitigating Aflatoxin Contamination in Groundnut through A Combination of Genetic Resistance and Post-Harvest Management Practices." Toxins 11, no. 6 (June 3, 2019): 315. http://dx.doi.org/10.3390/toxins11060315.

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Aflatoxin is considered a “hidden poison” due to its slow and adverse effect on various biological pathways in humans, particularly among children, in whom it leads to delayed development, stunted growth, liver damage, and liver cancer. Unfortunately, the unpredictable behavior of the fungus as well as climatic conditions pose serious challenges in precise phenotyping, genetic prediction and genetic improvement, leaving the complete onus of preventing aflatoxin contamination in crops on post-harvest management. Equipping popular crop varieties with genetic resistance to aflatoxin is key to effective lowering of infection in farmer’s fields. A combination of genetic resistance for in vitro seed colonization (IVSC), pre-harvest aflatoxin contamination (PAC) and aflatoxin production together with pre- and post-harvest management may provide a sustainable solution to aflatoxin contamination. In this context, modern “omics” approaches, including next-generation genomics technologies, can provide improved and decisive information and genetic solutions. Preventing contamination will not only drastically boost the consumption and trade of the crops and products across nations/regions, but more importantly, stave off deleterious health problems among consumers across the globe.
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Gummert, M., C. Balingbing, G. Barry, and L. Estevez. "Management options, technologies and strategies for minimised mycotoxin contamination of rice." World Mycotoxin Journal 2, no. 2 (May 1, 2009): 151–59. http://dx.doi.org/10.3920/wmj2008.1131.

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Анотація:
Ninety percent of the world's rice is produced and consumed in Asia. Millions of rice producers are resource-poor farmers with a rice area of less than one hectare. Yield increase and the introduction of double-cropping systems have ensured that rice production has kept up with an increasing demand. However, the increased quantities of grain and the second harvest, which is often in the wet season, have increased the problems in traditional postharvest systems. This can be particularly severe in the humid tropics, where post-harvest losses occur because of outdated management practices and technologies, and delays in post-harvest operations. Fungal infestation of rice grains can lead to discoloration, which results in price reductions in most markets. This can also result in rice being contaminated with mycotoxins, which is less visible to consumers. Contamination with ochratoxins, aflatoxins, and other mycotoxins have occasionally been reported in the literature. In the past, this was not seen as a significant problem and the focus was on other commodities such as maize and peanuts. However, recent studies and a massive recall of food products in Japan in September 2008, including sake, shoshu, and rice crackers made from imported rice from China and Vietnam, which were tested positive for aflatoxins, and also for pesticide residues, have renewed interest in looking at mycotoxin problems in rice. Exploratory studies in the Philippines compared best practice post-harvest management with the traditional management practices often used by smallholder farmers and small processors. It was concluded that synthesis of aflatoxin B1 is very likely in suboptimal post-harvest systems, with levels far above legislative limits. This indicates that there might be a considerable mycotoxin problem in rice from smallholder post-harvest operations. Improved post-harvest management options and technologies are available for diversified small-scale post-harvest systems. Small-scale combine harvesters, affordable and simple mechanical dryers and hermetic storage systems can help to avoid delays in the post-harvest chain and thus reduce mycotoxin contamination of rice. The development of strategies to scale out these improved practices and technologies to a large number of smallholder farmers will continue to be the main challenge.
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Tanko, Hakibu, Danielle Julie Carrier, Lijun Duan, and Ed Clausen. "Pre- and post-harvest processing of medicinal plants." Plant Genetic Resources 3, no. 2 (August 2005): 304–13. http://dx.doi.org/10.1079/pgr200569.

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Herbal medicine is used worldwide either as a sole treatment method or as part of a comprehensive treatment plan alongside orthodox methods of diagnosis and treatment. A survey reported that, in the USA, nearly one-sixth of women took at least one herbal product in 2000. Despite their widespread use, numerous reports show that the herbal products available to consumers are of variable quality. This disparity in quality of herbal preparations can be attributed to the fact that their production is complicated. To produce high-quality herbal products, attention must be paid to, among others, phytochemical variations due to plant breed, organ specificity, stages of growth, cultivation parameters, contamination by microbial and chemical agents, substitution, adulteration with synthetic drugs, heavy metal contamination, storage and extraction. This review focuses on organ specificity, seasonal variations, the effect of drying and storage, and the extraction of phytochemical constituents. Special emphasis is placed on the four most frequently used herbal products in the USA: echinacea, Ginkgo biloba, ginseng and St John's Wort.
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Mohamed, Somaya, Shadia Abd-El-Aziz, and Azza Naffa. "Anti-Contamination of Pathogenic Fungi on Post-Harvest Wheat Grains." Egyptian Journal of Phytopathology 42, no. 2 (December 31, 2014): 187–96. http://dx.doi.org/10.21608/ejp.2014.95593.

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Magoke, Krockenberger, Bryden, Alders, Mramba, and Maulaga. "Aflatoxin Contamination of Village Grains in Central Tanzania: Dietary and Agricultural Practices in Relation to Contamination and Exposure Risk." Proceedings 36, no. 1 (December 30, 2019): 20. http://dx.doi.org/10.3390/proceedings2019036020.

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Анотація:
A study was conducted in the semi-arid Manyoni District of Central Tanzania, involving eight village communities to: (1) assess aflatoxin contamination of village grains; and (2) gain knowledge on grain food practices and habits associated with aflatoxin risk. To address the respective objectives, random immediate post-harvest (n = 134) and following 6 month or more after storage grain samples (n = 157) were screened (AFLACHECKTM -VICAM), followed by quantitative HPLC determination of samples containing ≥10 µg/kg total aflatoxins. Responses were sought from 76 randomly selected adults by a questionnaire covering pre-harvest, harvest and post-harvest practices, food preparation and knowledge on food toxins. Aflatoxin contamination was particularly more significant in maize and groundnut samples ranging up to 198 µg/kg (mean = 25.46 µg/kg) in post-harvest grains and up to 351 µg/kg (mean = 50.83 µg/kg) in stored grains, well above the maximum limit of 10 µg/kg tolerated in foods for human consumption in Tanzania. Respondent questionnaires revealed farmers: had no knowledge of food toxins; received limited extension services; did not generally use irrigation, fertilisers or pesticides; relied on inadequate harvesting, drying and storage technologies; and frequently consumed unpolished grains. Village grains in Central Tanzania may contain high concentration of aflatoxins of potential significance to community health. Existing practices and lack of aflatoxin knowledge may facilitate contamination and exposure. Therefore, village farmers in Central Tanzania may benefit from better extension services, using livestock manure as fertilizer, access to drought tolerant seeds and better grain drying and storage technologies to reduce aflatoxin risk.
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Bist, Naresh Singh, and Pratibha Bist. "ROLE OF MICROORGANISMS IN POST-HARVEST LOSS OF AGRICULTURAL PRODUCTS: A REVIEW." Sustainability in Food and Agriculture 2, no. 1 (November 18, 2020): 01–04. http://dx.doi.org/10.26480/sfna.01.2021.01.04.

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Анотація:
The measurable quantitative (weight or volume) and qualitative (changed physical condition or characteristics) loss of agricultural products after harvest is considered as a post-harvest loss. Microbiological postharvest loss is one of the major types of postharvest loss and it refers to losses caused by microorganisms like moulds, yeasts, and bacteria. Microorganisms have a cosmopolitan distribution in the terrestrial ecosystem and are responsible for the contamination of agricultural products. Poor post-harvest management of agricultural products makes them susceptible to microbial contamination. Different genera of fungi, bacteria, protista even viruses are responsible for spoilage of food agricultural products rendering them unsuitable for consumption. Some microorganisms like Aspergillus, Penicillium, and Fusarium expel or produce mycotoxins on food material which is detrimental to human health. Thus, appropriate control measures should be applied to minimize microbial post-harvest loss for not only reducing risk to human health but also obtaining sustainable food security.
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Peles, Ferenc, Péter Sipos, Szilvia Kovács, Zoltán Győri, István Pócsi, and Tünde Pusztahelyi. "Biological Control and Mitigation of Aflatoxin Contamination in Commodities." Toxins 13, no. 2 (February 1, 2021): 104. http://dx.doi.org/10.3390/toxins13020104.

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Анотація:
Aflatoxins (AFs) are toxic secondary metabolites produced mostly by Aspergillus species. AF contamination entering the feed and food chain has been a crucial long-term issue for veterinarians, medicals, agroindustry experts, and researchers working in this field. Although different (physical, chemical, and biological) technologies have been developed, tested, and employed to mitigate the detrimental effects of mycotoxins, including AFs, universal methods are still not available to reduce AF levels in feed and food in the last decades. Possible biological control by bacteria, yeasts, and fungi, their excretes, the role of the ruminal degradation, pre-harvest biocontrol by competitive exclusion or biofungicides, and post-harvest technologies and practices based on biological agents currently used to alleviate the toxic effects of AFs are collected in this review. Pre-harvest biocontrol technologies can give us the greatest opportunity to reduce AF production on the spot. Together with post-harvest applications of bacteria or fungal cultures, these technologies can help us strictly reduce AF contamination without synthetic chemicals.
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Дисертації з теми "Post harvest contamination"

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Saucedo-Alderete, Raúl O. "Post-harvest spray treatments to reduce Salmonella contamination on cantaloupe surfaces." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/51831.

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Анотація:
Since the surfaces of cantaloupes are highly rough or irregular, Salmonella enteric and other bacteria can easily attach to these surfaces and are difficult to remove. Cetylpyridinium chloride (CPC) is the active ingredient of some antiseptic oral mouth rinses and has a broad antimicrobial spectrum with a rapid bactericidal effect on Gram-positive pathogens. Delmopinol hydrochloride (delmopinol) is a cationic surfactant that is effective for treating and preventing gingivitis and periodontitis. The application of delmopinol or CPC to cantaloupe surfaces may be an alternative post harvest technique to reduce the frequency and level of Salmonella contamination. Cantaloupe (Athena and Hale's Best Jumbo (HBJ) cultivars) rind plugs were inoculated with a broth culture of Salmonella Michigan. After 15 min, plugs were sprayed with 10 ml of a 1% delmopinol solution, or a CPC solution (0.5 or 1.0%) or distilled water (Control), and held at 37 oC for 1 hr or 24 hr. For additional samples, the chemical treatments were applied 15 min before pathogen inoculation. Melon plugs were submerged in Butterfield's Phosphate Buffer, shaken, sonicated and solutions were enumerated on Tryptic Soy Agar. The texture quality and color of additional melon samples were evaluated after delmopinol or CPC spray treatments and storage at 4 oC. A 1.0% application of CPC reduced Salmonella levels up to 2.34 log CFU/ml (Athena) and 4.95 log CFU/ml (HBJ) in comparison to the control (p<0.01). A 1.0% delmopinol treatment reduced Salmonella levels as much as 3.1 log CFU/ml in comparison to the control (p<0.01) on both cultivars. In general, the log recovery of Salmonella on cantaloupes treated with delmopinol or CPC solutions, after 1 hr storage, was significantly lower (p<0.05) than the recovery from control cantaloupes, but Salmonella recovery was not significantly different after 24 hr. No significant differences were observed in the texture and color of melons treated with delmopinol or CPC after 14 days. A surface spray application of delmopinol hydrochloride or cetylpyridinium chloride could be an alternative antimicrobial post-harvest treatment that could make cantaloupes surfaces more susceptible to sanitizers or enhance physical removal of bacteria.
Ph. D.
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Caldwell, Lucius. "The Use of Vinegar Vapor and Post-Harvest Biological Control to Reduce Patulin in Apple Cider." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/CaldwellL2009.pdf.

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Garbaba, Chemeda Abedeta [Verfasser]. "Development of Maize Post-harvest Loss Reduction Mechanism Owing to Mycotoxin-producing Fungi Contamination Along Agro-ecology and Supply Chain in Southwestern Ethiopia / Chemeda Abedeta Garbaba." Kassel : Universitätsbibliothek Kassel, 2019. http://d-nb.info/1177740249/34.

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Teixeira, Ricardo Rodrigues. "Avaliação de processos e tarefas em uma unidade movel para beneficiamento de tomate de mesa e alface." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256966.

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Анотація:
Orientador: Claudio Bianor Sverzut
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola
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Resumo: A cultura do tomateiro tem grande importância econômica e alimentar no país. A partir do momento da colheita ocorrem perdas cumulativas de qualidade em decorrência de fatores agroclimáticos como alta temperatura e variações constantes na umidade relativa do ar, além dos fatores relacionados ao manuseio pós-colheita, como danos mecânicos, local de manuseio e equipamentos inadequados para sanitização, classificação e embalagem, treinamento de colhedores e beneficiadores, além do armazenamento e transporte precários. Através de estudos das diversas tarefas que são necessárias a partir do momento da colheita dos tomates, foram analisados os processos para gerar subsídios para utilização de uma unidade móvel de beneficiamento de tomates de mesa com intuito de diminuir a perda pós-colheita, tendo como conseqüência um menor tempo de exposição do produto a condições adversas, mantendo a qualidade dos mesmos e consequentemente, aumentado sua vida de prateleira. A unidade móvel pode ser utilizada não somente para diminuição das perdas e manutenção da qualidade, mas também para melhorar o ambiente de trabalho, proporcionando uma infra-estrutura de apoio aos trabalhadores no campo.
Abstract: The tomato crop has economic and alimentary importance in Brazil. Since the harvesting the losses begins and goes cumulatively decreasing the quality of the product because, at first place, of the climate factors such as temperature, air humidity variation and at second, after harvested, because of the handling done during process from the field to the market, which means: selection, warehousing, cleaning, package, transportation and selling.. By studding the tasks necessary after the tomato harvesting, many information were analyzed given subsidies to use an itinerant unity to do the handling process of in nature tomato in order to avoid post harvest losses and, in consequence, letting the product less exposed to adverse conditions that occurs in the post harvest, kipping the quality and increasing the shelf life. In addition, the itinerant unity gives better work conditions as support for the field work too.
Universidade Estadual de Campi
Tecnologia Pós-Colheita
Doutor em Engenharia Agrícola
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Souza, Franciane Colares 1979. "Utilização combinada de radiação UV-C e atmosfera modificada para conservação do figo após a colheita." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/256804.

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Анотація:
Orientadores: Paulo Ademar Martins Leal, Antonio Carlos de Oliveira Ferraz
Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agrícola
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Resumo: O manejo inadequado é um fatores que afetam a qualidade de produtos agrícolas, conduzindo a perdas devido aos danos mecânicos e o desenvolvimento microbiano, agravado pelo armazenamento inadequado. No caso do figo, devido à limitada proteção oferecida pela epiderme e presença do ostíolo, o beneficiamento utilizando água não é recomendado, trazendo em pauta ações capazes de promover a desinfecção superficial sem afetar a qualidade do produto. Dentre os métodos físicos mais promissores para conservação de frutas estão a refrigeração, radiação ultravioleta (UV-C) e atmosfera modificada. Por outro lado, a utilização de métodos combinados apresenta vantagens devido sua ação sinérgica e complementar. Neste sentido, acredita-se que o uso combinado de métodos físicos pode trazer benefícios para a conservação de figos, principalmente voltada para o mercado externo, auxiliando na manutenção da qualidade do produto e redução da carga microbiana. Este trabalho teve como objetivo avaliar o desempenho da combinação dos tratamentos de atmosfera modificada passiva, atmosfera enriquecida com 100% de CO2 e radiação UV-C na conservação do figo 'Roxo de Valinhos'. As principais etapas foram as seguintes: (1) isolamento dos fungos causadores de podridao em figos 'Roxo de Valinhos' e teste de patogenicidade, utilizando métodos de inoculação de deposição de suspensão de esporos na epiderme do figo, com e sem perfuração, e com deposição sobre papel filtro, avaliando-se a incidência e a severidade dos patógenos com cálculo do Índice de Doença (ID); (2) identificação do nível de tolerância do figo à exposição da radiação UV-C de 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2; 2,64 kJ.m-2 e 4,00 kJ.m-2, armazenados à 10°C e 20°C, utilizando como parâmetro de qualidade a aparência visual; (3) avaliação do efeito da radiação UV-C no crescimento in vitro e in vivo dos fungos Rhizopus stolonifer, Lasiodiplodia theobromae e Alternaria alternata, utilizando-se valores de energia de radiação iguais a 0,00 kJ.m-2; 2,64 kJ.m-2; 4,00 kJ.m-2; 8,00 kJ.m-2 e 16,00 kJ.m-2 para os ensaios in vitro e iguais a 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2 e 2,64 kJ.m-2 para os ensaios in vivo, a 10ºC e 20ºC; (4) avaliação de desempenho do filme de polipropileno (PP) com espessuras de 25'mi'm, 30'mi'm e 50'mi'm na manutenção da qualidade de figos, avaliada pelos parâmetros perda de massa (PM), sólidos solúveis (SS), acidez titulável (AT), aparência visual e redução da incidência de podridão; (5) avaliação do efeito de atmosfera com 100% de CO2 por 4h, 8h e 12h, à 10ºC e 20ºC, na manutenção da qualidade e diminuição da carga microbiana no figo, avaliada pelos índices PM, SS, AT e aparência visual e (6) combinação do filme de PP de 30'mi'm com radiação UV-C de 1,32 kJ.m-2 e com a exposição à atmosfera com 100% de CO2 durante 4h. Os resultados evidenciaram que a utilização isolada do filme de PP de 30'mi'm, radiação UV-C e exposição à 100% de CO2 mostrou-se eficiente na manutenção da qualidade das frutas, sobretudo quando se utiliza o armazenamento refrigerado. O uso combinado do filme de PP de 30'mi'm com atmosfera modificada com 100% de CO2, representa uma alternativa para o armazenamento do figo, mesmo quando não se utiliza refrigeração, em função da redução da carga microbiana e manutenção da qualidade
Abstract: The main factor affecting quality of agricultural products is the inadequate management, leading to considerable losses due to mechanical damage and fungal contamination, aggravated by improper storage. The fig vulnerability is amplified due to the presence of the ostiole, a peculiar fig orifice, acting as an open door to contamination. Since aqueous sanitization is not recomended, other methods should be searched to promote surface sanitization without affecting the quality of the product. Some promising methods are cooling, ultraviolet radiation (UV-C) and modified atmosphere. A combined method also has advantages because of their synergistic effect on inhibiting microbial growth, and thus maintaining the nutritional and visual qualities of the product. Moreover, the combined use of physical methods, to improve the fig shelf life, potentially can increase business opportunities, specially in the international market. The main objective of this work was to evaluate the performance of the combination of modified atmosphere and UV-C radiation on 'Roxo de Valinhos' fig conservation. To attain this general goal several intermediate steps were performed: (1) fungi rot identification and associated pathogenicity using inoculation by deposition on filter paper to evaluate disease incidence and contamination severity; (2) UV-C radiation fig tolerance identification using energy levels of 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2; 2,64 kJ.m-2 and 4,00 kJ.m-2, followed by storage at 10ºC and 20ºC; (3) evaluation of the effect of UV-C radiation on Rhizopus stolonifer, Lasiodiplodia theobromae and Alternaria alternata fungi growth, for in vitro and in vivo tests, using energy irradiation of 0,00 kJ.m-2; 2,64 kJ.m-2; 4,00 kJ.m-2; 8,00 kJ.m-2 and 16,00 kJ.m-2 for the in vitro test, and 0,00 kJ.m-2; 0,70 kJ.m-2; 1,32 kJ.m-2 e 2,64 kJ.m-2 for the in vivo test, at 10ºC and 20ºC; (4) evaluation of the polypropylene (PP) in maintaining the quality, using film thicknesses of 25'mi'm, 30'mi'm and 50'mi'm; (5) evaluation of the fig exposition to 100% CO2 modified atmosphere for 4h, 8h and 12h, followed by storage at 10ºC and 20ºC, in maintaining quality and keeping the microbiological load low and (6) evaluation of the combined use of 30'mi'm PP film with UV-C irradiation of 1,32 kJ.m-2 and 100% CO2 modified atmosphere during 4h. Results have shown that the use of the 30'mi'm PP film, radiation UV-C of 1,32 kJ.m-2 and exposition to 100% of CO2 for 4h was effective in maintaining the quality of the fruits, specially when refrigerated storage is employed. It was concluded that combined use of the 30'mi'm PP film with high CO2 concentration represents an alternative to non refrigerated fig storage, due to the reduction of the microbial load
Doutorado
Tecnologia Pós-Colheita
Doutora em Engenharia Agrícola
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Mylona, Kalliopi. "Fusarium species in grains : dry matter losses, mycotoxin contamination and control strategies using ozone and chemical compounds." Thesis, Cranfield University, 2012. http://dspace.lib.cranfield.ac.uk/handle/1826/7876.

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This Project identified the relationships between storage conditions, dry matter losses (DMLs) caused by Fusarium species in cereal grains and mycotoxin contamination and assessed novel control strategies for post-harvest grain management including chemical control and ozone. F. graminearum, F. verticillioides and F. langsethiae were inoculated on wheat, maize and oats and stored under environmental conditions where marginal to optimum spoilage and mycotoxin contamination can occur. DMLs were calculated from the CO2 produced and were significantly correlated with deoxynivalenol (DON), zearalenone (ZEA), fumonisins (FUMs) and T-2 and HT-2 toxins respectively. Mycotoxin levels in wheat and maize exceeded the EU legislative limits with 0.9-1% DMLs. Therefore, CO2 monitoring during storage can indicate the level of contamination in a stored batch. Using CO2 production data at different water activity (aw) and temperature conditions, the environmental regimes at which F. langsethiae can grow and contaminate oats with T-2 and HT-2 toxins were identified for the first time. Five acids were examined in vitro and little effect was observed on Fusarium growth, in the aqueous form, while the effect on mycotoxin production varied. Dissolved in ethanol, adipic, fumaric and ferulic acids inhibited fungal growth and controlled DON and FUMs, but T-2 toxin was stimulated by the ethanol. Two garlic essential oils, propyl-propylthiosulfinate (PTS) and propyl propylthiosulfonate (PTSO) were studied for the first time. In vitro, 200 ppm reduced fungal growth (50-100%) and mycotoxin production by >90%. The efficacy was species-dependent. In naturally contaminated oats of 0.93 aw stored for 20 days, 16 ppm PTSO reduced T-2 and HT-2 toxins by 66% and ochratoxin A (OTA) by 88%, while 200 ppm PTS reduced OTA by 95%. In wheat, 100 ppm PTS reduced DON and ZEA and 300 ppm PTS reduced fumonisins by 40-80%. PTSO:PTS (1:1) at 400 and 600 ppm was very effective against DON and ZEA in wheat of 0.92 aw. Ozone (O3) exposure at 200 ppm for 30 min delayed Fusarium spore germination on media of 0.98 aw and inhibited germination at 0.94 aw. O3 was more effective against fungal spores than mycelium and little effect was observed on growing cultures. In vitro, mycotoxin production after exposure depended on the stage of life of the fungi. O3 reduced fungal populations in grains. Mycotoxin production in wet grains treated with 100-200 ppm O3 for 60 min and stored for up to 30 days was reduced or completely inhibited, depending on the species and the exposure system. Simultaneous drying of the grain due to the O3 passage was observed.
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Noviyanti, Fnu. "Shiga-toxin Escherichia coli contamination in cattle post harvest." Thesis, 2018. http://hdl.handle.net/2097/38836.

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Master of Public Health
Department of Diagnostic Medicine and Pathobiology
Robert Larson
Among animal products consumed by humans, ground beef has been reported as one of the most common vehicles for STEC outbreaks in humans. In the United States, cull dairy cattle contribute as one of the primary sources for ground beef. The objective of this study was to determine the prevalence and concentration of 7 Shiga toxin-producing Escherichia coli serogroups (STEC-7; O26, O103, O111, O121, O45, O145, and O157) and associated virulence genes (Shiga toxin 1 and 2 (stx1, stx2), intimin (eae), and enterohomolysin (ehxA)) in the feces of cull dairy cattle processed in commercial slaughter plants during summer months. Fecal swab samples (n=183) were collected from three processing plants, one in California and two in Pennsylvania. At each plant at least 60 to 65 cattle were selected, and the samples were obtained by swabbing the mucosal surface of the recto-anal junction using a sterile cotton-tipped applicator. To determine prevalence, all samples were subjected to culture-based detection methods that included enrichment, serogroup-specific immunomagnetic separation and plating on selective media, followed by polymerase chain reaction for serogroup confirmation and virulence gene detection. Pre-enriched fecal samples were subjected to spiral plating to determine the concentration of STEC-7. A sample was considered STEC positive if a recovered isolate harbored one of the 7 target O genes, stx1, and/or stx2. Of the 183 fecal swab samples collected, 23 (12.6%) harbored at least one O157, O26, O103, or O111 serogroup, with their associated virulence genes. However, none of the fecal samples from this cattle population carried STEC at high-levels (>10⁴ CFU/g). This study has provided important information on STEC-7 prevalence from dairy cattle that enter the ground beef processing system. However, there is still a need to determine prevalence and concentration of STEC in cull dairy cattle during winter months as well as in other sources of ground beef production (e.g., imported lean beef, cull beef).
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Villarreal, Silva Mariana. "Simulation of Contamination Through the Post-Harvest Environment Using Surrogate Organisms." Thesis, 2010. http://hdl.handle.net/1969.1/ETD-TAMU-2010-08-8542.

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The beef industry has made tremendous strides in reducing pathogen contamination on carcasses. Multiple antimicrobial interventions have been validated for their use during harvesting. Information in regards to cross-contamination with pathogens in the post-harvest environment is limited. Surrogate microorganisms for enteric pathogens are commonly used to validate antimicrobial interventions and might allow for the simulation of cross-contamination through the post-harvest environment. The purpose of this study was to determine how the post-harvest environment impacts the direct and indirect transmission of pathogens. This was achieved by using fluorescent protein-marked surrogate strains of Escherichia coli O157:H7 and Salmonella spp. from inoculated carcasses to the adjacent ones and to the equipment and facility in three different abattoirs. Thirteen hide-on carcasses were inoculated using a gelatin-based slurry containing three nonpathogenic fluorescent protein-marked strains of E. coli biotype I. In order to determine direct and indirect cross-contamination, inoculated and adjacent carcasses were sampled (300 cm2) during the harvesting process at different stages: after hide opening (AHO), prior to evisceration (PE), after evisceration (AE), after splitting (AS), and after final intervention (AFI). Environmental samples consisting of the floor, walls, and air were tested as well as personal equipment including gloves, boots, and aprons. Equipment including hand knives, air knives, meat hooks, hide puller and split saw were also sampled. Results showed evidence of cross-contamination between inoculated carcasses and the adjacent non-inoculated ones for all abattoirs. Although this occurred in all abattoirs, surrogate counts on carcasses were below detectable levels (<1.4 log CFU/cm2) after antimicrobial interventions. Surrogates were found in low levels for all environmental samples. However surrogate counts from equipment such as knives, split saws, meat hooks, and hide puller were more frequently detected (15 percent) than those found on the floor, air and walls samples (10 percent). In the case of aprons, boots, and gloves, the prevalence of countable surrogate samples was 7 percent.
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Chae, Minjung. "Low-temperature post-harvest processing for reducing Vibrio parahaemolyticus and Vibrio vulnificus in raw oysters." Thesis, 2007. http://hdl.handle.net/1957/5705.

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Oysters are filter-feeding bivalves, which filter water for nutrients and often accumulate contaminants and human pathogens such as Vibrio parahaemolyticus and Vibrio vulnificus naturally occurring in the marine environment. These naturally occurring pathogens have been frequently isolated from raw shellfish, particularly oyster, in the United States and are recognized as the leading causes of human gastroenteritis associated with seafood consumption. Human illness caused by consumption of raw oyster contaminated with V. parahaemolyticus and Vibrio vulnificus typically results in reduced sales of oysters and a consequent significant financial burden for the producers. The United States produces more than 27 million pounds of oysters each year with a large portion of them being produced from the coastal water of the Gulf of Mexico. It is estimated that 20 million Americans eat raw shellfish and consumption of raw oyster is responsible for about 95% of all deaths associated with seafood consumption in the U.S., making raw oysters one of the most hazardous seafoods. Several post-harvest processes, including low temperature pasteurization, freezing, high pressure processing and irradiation, have been reported capable of reducing Vibrio contamination in raw oysters. However, most of them require either a significant amount of initial investment or operation costs, and oysters are often killed during processing. Cost-effective post-harvest processing for reducing V. parahaemolyticus in raw oysters without significant adverse effects on the oysters remains to be developed. This study was conducted to determine impacts of low-temperature (15, 10 and 5°C) depuration and frozen storage on reducing V. parahaemolyticus and V. vulnificus in raw oysters. Depuration of the Gulf oyster (Crassostrea virginica) with electrolyzed oxidizing (EO) water (chlorine, 30 ppm; pH 2.82; oxidation-reduction potential, 1,131mV) containing 3% NaCl was found ineffective on reducing both V. parahaemolyticus and V. vulnificus in the oysters. Reductions of V. parahaemolyticus and V. vulnificus in oyster after 48 h of EO water depuration at 22°C were limited to 0.7 and 1.4 log MPN/g, respectively. Depuration with EO water at lower temperatures did not enhance reductions of Vibrio in the oysters. Greater reductions of V. parahaemolyticus (1.2 log MPN/g) and V. vulnificus (2.0 log MPN/g) were observed when the oysters were depurated with artificial seawater (ASW) at room temperature (22°C) for 48 h. Decreasing temperature of ASW to 15°C for depuration significantly increased the reductions of V. parahaemolyticus and V. vulnificus to 2.1 and 2.9 log MPN/g, respectively, after 48 h of process. However, depuration of oyster in ASW at 10 and 5°C were found less effective than at 15°C in reducing Vibrio in the Gulf oysters. An extended depuration with ASW at 15°C for 96 h was capable of achieving 2.6 and 3.3 log MPN/g of reductions of V. parahaemolyticus and V. vulnificus, respectively, in the Gulf oysters. Study of effects of frozen storage at -10, -23 and -30°C on reducing V. parahaemolyticus in raw half-shell Pacific oyster (Crassostrea gigas) found that the population of the bacterium decreased faster in oysters stored at -10 than at -23 or -30°C. Holding half-shell Pacific oyster at -10°C for three months or at -23°C for four months was capable of achieving a greater than 3-log (MPN/g) reduction of V. parahaemolyticus in the Pacific oyster.
Graduation date: 2008
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Karmakar, Kapudeep. "Elucidating the mechanism of interaction of Salmonella with plants." Thesis, 2018. https://etd.iisc.ac.in/handle/2005/4730.

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Salmonella, is an established pathogen of members of the kingdom Animalia. Its principal species S. enterica serovars Typhi, Paratyphi and Typhimurium can cause various diseases ranging from typhoid fever to gastroenteritis in different organisms. Post harvest contamination of fruits and vegetables by Salmonella is one of the causes of food-borne outbreaks. Controlling the spread of Salmonella at field level is very important in order to prevent various food-borne outbreaks. In this regard, the microbiota of plants can play a crucial role. In the present study, we made an effort to describe one such approach to limit Salmonella population in plant. Biocontrol of phyto-pathogens is an environmental friendly alternative to protect plants. Keeping this in view, endophytes from different organs of tomato plant (INDAM 535) were isolated and the growth of Salmonella was further analyzed in the culture supernatant of these endophytes. Spent media of Microbacterium paraoxydans and Lysinibacillus microides (isolated from roots) was found to have an inhibitory affect on Salmonella growth. These organisms were observed to reduce Salmonella CFU in arabidopsis as well as tomato roots. Their bacteriostatic activity was further verified. A quorum sensing/quenching based signaling between endophyte and Salmonella was observed. The second approach in controlling Salmonella colonization involves the antibacterial properties of the plant secondary metabolites. Beta vulgaris roots (a common salad vegetable) having high concentration of betalains was used to treat arabidopsis roots inoculated with Salmonella. Post treatment, a decrease in Salmonella burden was observed in roots of susceptible plants. These approaches can further be utilized to bring down the Salmonella population in soil. Thus, inclusion of these crops in the crop rotation or as a mixed/inter crop can be a fruitful tool to reclaim the Salmonella contaminated soil.
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Частини книг з теми "Post harvest contamination"

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Kodandaram, M. H., Y. Bijen kumar, Kaushik Banerjee, A. B. Rai, and B. Singh. "Pre- and Post-Harvest Pesticide Contamination Management for Production of Quality Vegetables." In Advances in Postharvest Technologies of Vegetable Crops, 443–83. Waretown, NJ : Apple Academic Press, 2018. | Series: Postharvest biology and technology: Apple Academic Press, 2018. http://dx.doi.org/10.1201/9781315161020-17.

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Ricke, S. C. "Microbial ecology of eggs: a focus onSalmonellaand microbial contamination in post-harvest table shell egg production." In Quantitative Microbiology in Food Processing, 416–41. Chichester, UK: John Wiley & Sons, Ltd, 2016. http://dx.doi.org/10.1002/9781118823071.ch21.

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Dubey, N. K., Priyanka Singh, Bhanu Prakash, and Prashant K. Mishra. "Plant Chemicals in Post Harvest Technology for Management of Fungal, Mycotoxin and Insect Contamination of Food Commodities." In Plant Defence: Biological Control, 195–208. Dordrecht: Springer Netherlands, 2011. http://dx.doi.org/10.1007/978-94-007-1933-0_8.

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Dubey, Nawal Kishore, Prashant Kumar Mishra, Akash Kedia, and Bhanu Prakash. "Fungal and Mycotoxin Contamination of Herbal Raw Materials and Prospects of Higher Plant Products as Plant-Based Preservatives During Post-Harvest Processing." In Microbial Diversity and Biotechnology in Food Security, 495–504. New Delhi: Springer India, 2014. http://dx.doi.org/10.1007/978-81-322-1801-2_45.

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Vishunavat, Karuna, Kuppusami Prabakar, and Theerthagiri Anand. "Seed Health: Testing and Management." In Seed Science and Technology, 335–64. Singapore: Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-19-5888-5_14.

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AbstractHealthy seeds play an important role in growing a healthy crop. Seed health testing is performed by detecting the presence or absence of insect infestation and seed-borne diseases caused by fungi, bacteria, and viruses. The most detrimental effect of seed-borne pathogens is the contamination of previously disease-free areas and the spread of new diseases. Sowing contaminated or infected seeds not only spreads pathogens but can also reduce yields significantly by 15–90%. Some of the major seed-borne diseases affecting yield in cereals, oilseeds, legumes, and vegetables, particularly in the warm and humid conditions prevailing in the tropical and sub-tropical regions, are blast and brown spot of rice, white tip nematode and ear-cockle in wheat, bacterial leaf blight of rice, downy mildews, smuts, head mould, seedling rots, anthracnose, halo blight, and a number of viral diseases. Hence, detection of seed-borne pathogens, such as fungi (anthracnose, bunt, smut, galls, fungal blights), bacteria (bacterial blights, fruit rots, cankers), viruses (crinkle, mottle, mosaic), and nematodes (galls and white tip), which transmit through infected seed to the main crop, is an important step in the management strategies for seed-borne diseases. Thus, seed health testing forms an essential part of seed certification, phytosanitary certification, and quarantine programmes at national and international levels. Detection of seed-borne/transmitted pathogens is also vital in ensuring the health of the basic stock used for seed production and in maintaining the plant germplasm for future research and product development. Besides the precise and reproducible testing methods, appropriate practices during seed production and post-harvest handling, including seed treatment and storage, are important components of seed health management and sustainable crop protection.
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Camacho Martinez, Silvia Vanessa, Mahdiyeh Hasani, Lara Jane Warriner, and Keith Warriner. "Advances in sanitising techniques and their assessment for assuring the safety of fresh produce." In Advances in ensuring the microbiological safety of fresh produce, 245–80. Burleigh Dodds Science Publishing, 2023. http://dx.doi.org/10.19103/as.2023.0121.16.

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Fresh produce accounts for the majority of foodborne illness outbreaks and >30% of food waste attributed to premature spoilage. To date, pathogen control has been focused on the pre-harvest stage, in the form of testing and Good Agricultural Practice, given the limited efficacy of post-harvest washing to remove field-acquired contamination. However, the open nature of production systems and unreliability of testing have led to increased attention on post-harvest interventions as a type of ‘pasteurisation’ step. Attempts to improve the washing process involve identifying and maintaining sufficient free chlorine in wash tanks to prevent cross-contamination events. Alternative sanitisers to chlorine have also been evaluated although at best, minimize cross-contamination rather than support decontamination. This has led to the development of aqueous-free produce decontamination methods with gas-phase, gas plasma and hydroxyl-radical treatments showing promise. The development of a standard validation method to compare technologies is discussed along with future directions.
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Waithaka Ng’ang’a, Zacharia, and Eric Niyonshuti. "Animal Feeds Mycotoxins and Risk Management." In Mycotoxins and Food Safety - Recent Advances [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.102010.

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The demand for livestock products is the main factor affecting the demand for livestock feeds worldwide. However, animal feed safety has gradually become more important, with mycotoxins representing one of the most significant hazards. Mycotoxins are toxic secondary metabolites produced naturally by fungi that grow on various agriculture commodities. Aflatoxin, fumonisin, ochratoxin, trichothecene, and zearalenone are the more prevalent mycotoxins in animal feeds. Some of mycotoxins impacts include; loss of animal and human health, reduced animal productivity, increased veterinary service costs, feed disposal and increased research costs which enhance the importance of mycotoxins detoxification. Contamination of feeds may occur both during pre-harvest and post-harvest. The purpose of this chapter is to review the most prevalent mycotoxins in animal feeds, reveal the origin of mycotoxins contamination and the possible risks they pose to feeds and livestock. This chapter also gives an overview of the most important factors that influence mold growth and mycotoxin production as well as the economic impacts of mycotoxins. To the end of this chapter, mycotoxins preventive methods, both preharvest and postharvest, are well discussed.
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Magan, Naresh, Esther Garcia-Cela, Carol Verheecke-Vaessen, and Angel Medina. "Advances in post-harvest detection and control of fungal contamination of cereals." In Advances in postharvest management of cereals and grains, 339–62. Burleigh Dodds Science Publishing, 2020. http://dx.doi.org/10.19103/as.2020.0072.14.

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"Post-harvest strategies to reduce enteric bacteria contamination of vegetable, nut and fruit products." In Handbook of Organic Food Safety and Quality. CRC Press, 2007. http://dx.doi.org/10.1201/9781439824566.pt4.

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Johannessen, Gro S. "Post-harvest strategies to reduce enteric bacteria contamination of vegetable, nut and fruit products." In Handbook of Organic Food Safety and Quality, 433–53. Elsevier, 2007. http://dx.doi.org/10.1533/9781845693411.4.433.

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Тези доповідей конференцій з теми "Post harvest contamination"

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Kutlakhmedov, Yu, V. Davydchyk, A. Jouve, and N. Grytsiuk. "Evaluation the Efficacy of the Turf-Cutter Soil Decontamination Technology." In ASME 2001 8th International Conference on Radioactive Waste Management and Environmental Remediation. American Society of Mechanical Engineers, 2001. http://dx.doi.org/10.1115/icem2001-1167.

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Abstract The testing begun in the framework of the CEC project ECP-4 “Decontamination technologies and strategies” have allowed to develop and to test new technology of the polluted soils decontamination by removal of the thin turf layer by the vibrating blade of the special machine (Turf-Cutter). The experiments were conducted at the radioactively contaminated soils of Ukraine and Belarus during 1992–2000. The machine “TURF HARVESTER” (USA) was used in the experiment. The first testing of the method was conducted on the well turfed radioecological polygon “Buryakovka”, 4 km from the Chernobyl NPP, with levels of contamination: 100 Ci/km2 by Cs-137, 80 Ci/km2 by Sr-90, 7 Ci/km2 by Pu-239. As the preliminary researches have shown, about 95% of the radionuclides were concentrated in the upper layer of the unploughed soil. In an outcome of tests on a selected plot the decontamination factor (Fd) 25–40 for different radionuclides was obtained. After removal of turf and opening the soil surface, the wind soil erosion and secondary resuspension the radionuclides was expect. It has not taken place, as special researches on an evaluation of the wind resuspension of radionuclides by the soil particles after the turf harvesting. This can be explained as follows. The vibrating blade does not decondence and decompose the soil layer remaining. At the same time, the thin turf and soil layer removal saves the vegetation regenerating organs and roots, which allows the grass restoration and surface fixation within one month after the experiment. The second test of a method was conducted on a polygon “Chistogalovka”, 3 km of the NPP. A high level of the radioactive contamination (150 Ci/km2 by Cs-137) and the weak turf cover of the rugged sand surface characterized the polygon. The turf removal at this polygon has allowed to receive Df = 10–15. Another testing was made at the Belorussian part of the Zone, which have demonstrated the possibility of the selected turf removal under the spotty radioactive contamination. The field gamma-spectrometer “Corad”, produced by the Kurchatov Institute (Russia), was used for the operative definition the highly contaminated spots. The selected removal of the mostly contaminated spots decreased the mass of the turf removed by 70%, obtaining the Df = 5–7. Next testing was conducted at the village Miliach (Rivne Province, Dubrovitsa district, Ukraine) at the pasture “Stav” with the contamination level by Cs-137 about 5 Ci/km2. This pasture was not influenced by any post-accident countermeasures. After the radioactive turf removal (Df = 15–20), the fodder grass was sow. The grass contamination was 15 times less, comparing to the control. The experimental fattening of 10 cows by a grass, skewed on the decontaminated plot, within 10 days, was carried on. A comparison the contamination of the milk from the experimental cows, which were fed by a grass of the turf-harvested plot, and the milk of the control cows, has shown the milk Df about 11 in 1993. The data obtained show high efficiency of the decontamination technology for the polluted soils based on the turf removal by the vibrating blade. Decontamination factor about 7–15 for the sandy and dusty-sandy soils with a weak turf layer up to 20–40 for the organic and wet silty soils with a strong turf layer was obtained. Important thing is, the best Dfs were obtained for the soils, which are critical on the intensity of the root uptake of the radionuclides. The high ecological and radioecological safety of the Turf-Cutter technology of the soil decontamination is also to be considered. The thin turf and soil layer removal does not deteriorate dramatically the migration situation and at the same time does not avoid the damaged ecosystem self-restoration. The volume of the matter harvested is comparatively low, because of the thin cutting. Being stored in the walls 2,5 m height, it occupies less 5% of the territory decontaminated, and the risk of migration the radionuclides outside the storage sites is comparative to those of the primary soil layouts. The field testing of the Turf-Cutter technology show correlation of its efficacy to the soil types, vegetation cover and the landscape conditions of the contaminated territory. It allowed, using some elements of the GIS-technologies and cartographic modeling, to prepare special evaluation and zonification the territories contaminated on the efficacy of the Turf-Cutter technology, and to identify the areas best for it’s mostly effective application. Following investigations confirm stable, long-term character of the improvements carried out. The sampling of 2000 at Miliach experimental plot shows the decontamination factor 10–11 for the grass and about 8 for milk. Moreover, as the Cs-137 still remains at the upper part of the soil profile, the Turf-Cutter technology is still actual for the territories of the post-Chernobyl radioactive contamination. Obviously, it can be suitable also for the removal of any other surface pollutant from the soil.
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