22 research outputs found

    Living Environment Field Trips in Wyoming and Genesee Counties, New York

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    The purpose of field trips is to engage students in hands on or real world learning opportunities. Science fairs and field trips are two examples of how students can experience out of classroom activities. Through these activities, students may understand or practice an aspect of a topic as experienced in the real world, outside of the school setting (Tal, et. al., 2014); exploring skills and physical beings, having discussions with historians or scientists, and synthesizing or analyzing information (Rohlf, 2015). Especially in science, new technology and knowledge is ever changing. Field trips allow students to practice or use technology that many schools or organizations are unable to purchase for student use. Many students’ families cannot provide or support students’ learning by taking them to outside learning events or activities (DeSouza, 2016). Through expeditionary learning, or field trips, that are available to students in school or through after school programs, all students are able to experience how individuals of all races and backgrounds can work together to form a successful scientific environment. By having students attend field trips, they not only are learning about science, but are practicing other life skills such as communication (Bozdogan, 2012). Students not only need to communicate with each other during tasks or about observations, but often need to communicate teachers or research guides. Communication skills are essential for all students whether they enter the science field after the completion of high school or not. Furthermore, field trips allow students to pursue areas of interest and may influence their entrance into the STEM field post- high school (Schmidt & Kelter, 2017). Field trips allow students to experience aspects of learning that are not able to be practiced in the classroom setting (Rohlf, 2015). Although all of the aforementioned are beneficial for students and their learning, field trips are often still questioned for their integrity. Learning, balanced with fun, is the basis of the concern; do students actually learn on field trips or does the fun atmosphere overtake student learning

    Quorum sensing em cepas de enterococcus faecium, enterococcus faecalis e bacillus cereus isoladas do processamento de ricota

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    The quorum sensing phenomenon is a process of intra- and inter-species microbial communication involving the production and detection of extracellular signaling molecules. The autoinducer AI-2 has been proposed to serve as a ‘universal signal’ for interspecies communication. This study aimed to evaluate the capability of Enterococcus faecium, Enterococcus faecalis, and Bacillus cereus strains isolated from ricotta processing to produce quorum sensing signalling molecules (AI-2). The strains were evaluated for the presence of the luxS gene using the polymerase chain reaction. AI-2 quorum sensing signalling molecules were measured in relative light units (RLUs) using a luminometer. A total of 74% of E. faecium, 91% of E. faecalis, and 95% of B. cereus isolates were positive for luxS gene. In addition, the induced bioluminescence in Vibrio harveyi BB170 was observed in all strains, indicating the presence of the AI-2 autoinducer482FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2010/10507-7O fenômeno quorum sensing corresponde a um processo de comunicação intra e interespécies microbianas e é mediado por sinais químicos extracelulares, denominados moléculas sinalizadoras ou auto indutoras (AI). A molécula AI2 está envolvida na comunicação interespécies, denominada sistema “universal” de comunicação. Este estudo teve como objetivo avaliar a capacidade de Enterococcus faecium, Enterococcus faecalis e Bacillus cereus isolados do processamento de ricota em produzir moléculas sinalizadoras de Quorum sensing (AI-2). Os isolados foram avaliados quanto à presença do gene luxS utilizando a reação em cadeia da polimerase (PCR). As moléculas sinalizadoras (AI-2) foram medidas em unidades relativas de luz (RLU) através de um luminômetro. Um total de 74% dos isolados de E. faecium, 91% de E. faecalis e 95% de B. cereus foram positivos para o gene luxS. Além disso, todos os isolados apresentaram capacidade de induzir o fenômeno de bioluminescência em Vibrio harveyi BB170, indicando a presença de auto indutores AI-

    Tracking of would listeria monocytogenes in processing industries of frescal cheese Latin type, in the United States of America, using the molecular subtipagem

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    Orientadores: Arnaldo Yoshiteru Kuaye, Kathryn J. BoorTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Os queijos frescais estilo Hispânico são alimentos de alto risco à contaminação por L. monocytogenes e já foram associados à pelo menos dois surtos de listeriose nos Estados Unidos da América. O conhecimento maior das fontes de contaminação por L. monocytogenes no processamento de queijos frescos tipo Hispânico é crítico para permitir o desenvolvimento de estratégias mais eficazes para o controle deste perigo. Neste trabalho, foi realizado um diagnóstico da contaminação por L. monocytogenes em três indústrias processadoras de queijos frescais tipo Hispânico, nos Estados Unidos. Um total de 246 amostras ambientais foi coletado e analisado para L. monocytogenes utilizando-se o método preconizado pela ¿Food and Drug Administration¿ (FDA) e o método ¿Biosynth L. monocytogenes detection system¿ (LMDS). As amostras de queijo, produzidos nestas indústrias (n=111), foram analisadas utilizando-se o método da FDA, modificado pela inclusão dos meios de cultura ¿L. monocytogenes plating medium¿ (LMPM) e ¿Listeria monocytogenes confirmatory plating medium¿ (LMCM) utilizados no método LMDS. L. monocytogenes foi detectada em 6,3% dos queijos e 11,0% das amostras ambientais. Dentre as amostras ambientais, aquelas obtidas de caixa vazada de plástico, dreno e piso apresentaram alta ocorrência de L. monocytogenes, com taxas de 55,6%, 30,0% e 20,6%, respectivamente. Apenas uma indústria apresentou resultados positivos em amostras de queijos e de superfícies que contatavam o alimento. O método da FDA mostrou maior sensibilidade do que o método LMDS para detecção de L. monocytogenes em amostras ambientais, e a inclusão dos meios LMPM e LMCM não melhorou a performance do método do FDA para detecção do patógeno em queijos. A subtipagem molecular, através da análise alélica dos genes de virulência actA e hly e da ribotipagem automatizada, foi utilizada para traçar a contaminação por L. monocytogenes nas indústrias. O ribotipo DUP-1044A, que havia sido previamente associado a surtos de listeriose humana em vários estados nos Estados Unidos em 1998, foi o subtipo mais comumente identificado (20/36 isolados) e foi isolado em 2 estabelecimentos. Este ribotipo se mostrou persistente e amplamente disseminado em uma das indústrias, onde foi também responsável pela contaminação do produto final. Nossa hipótese é que cepas deste ribotipo tenham habilidade específica em permanecer no ambiente de processamento. Apesar dos surtos de listeriose terem sido associados a queijos Hispânicos produzidos com leite não pasteurizado, os resultados obtidos neste trabalho revelam que a permanente contaminação ambiental pode representar outra fonte importante de contaminação do produto finalAbstract: Latin-style fresh cheeses, which have been linked to at least two human listeriosis outbreaks in the US, are considered to be high risk foods for Listeria monocytogenes contamination. We evaluated L. monocytogenes contamination patterns in three Latin-style fresh cheese processing plants to gain a better understanding of L. monocytogenes contamination sources in the manufacture of these cheeses. Over a 6-month period, 246 environmental samples were collected and analyzed for L. monocytogenes using both the Food and Drug Administration (FDA) method and the Biosynth L. monocytogenes detection system (LMDS). Finished cheese samples from the same plants (n=111) were also analyzed by the FDA method, which was modified to include L. monocytogenes plating medium (LMPM) and the L. monocytogenes confirmatory plating medium (LMCM) used in the LMDS method. L. monocytogenes was detected in 6.3% of cheese and 11.0% of environmental samples. Crates, drains and floor samples showed the highest contamination rates with 55.6%, 30.0% and 20.6% L. monocytogenes positive samples, respectively. Finished products and food contact surfaces were positive in only one plant. The FDA method showed a higher sensitivity than the LMDS method for detection of L. monocytogenes from environmental samples. The addition of LMPM and LMCM media did not further enhance the performance of the FDA method for L. monocytogenes detection from finished products. Molecular subtyping (PCR-based allelic analysis of the virulence genes actA and hly and automated ribotyping) was used to track contamination patterns. Ribotype DUP-1044A, which had previously been linked to a 1998 multistate human listeriosis outbreak in the US, was the most commonly identified subtype (20/36 isolates) and was isolated from two plants. This ribotype was persistent and widespread in one factory, where it was also responsible for the contamination of finished products. We hypothesize that this ribotype may represent a clonal group with a specific ability to persist in food processing environments. While previous listeriosis outbreaks were linked to Latin-style fresh cheeses made from unpasteurized milk, the presence of this organism in pasteurized cheese products illustrates that persistent environmental contamination also represents an important source of finished product contaminationDoutoradoDoutor em Tecnologia de Alimento

    Contagem de listeria spp pelo metodo do numero mais provavel (NMP), avaliação de sua ocorrencia em carnes de frango e da eficiencia de sanitizantes na redução da contaminação por Listeria monocytogenes

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    Orientador: Arnaldo Yoshiteru KuayeDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de AlimentosResumo: Atualmente a L. monocytogenes é considerada um patógeno de importância em alimentos, pois vários surtos e casos de listeriose associados ao consumo de alimentos têm sido relatados, incluindo os produtos de frango. O aumento da produção brasileira de carnes de aves, a redução de preço no mercado interno e conseqüente aumento do consumo e a falta de métodos oficiais para a quantificação de L. monocytogenes em alimentos, principalmente os in natura, levaram ao desenvolvimento deste projeto numa tentativa de quantificá-la para que limites máximos de tolerância possam ser propostos. Amostras resfriadas de peito e de frango inteiro obtidas no comércio varejista, foram submetidas a quantificação de Listeria spp pelo método do Número Mais Provável (NMP) utilizando-se: a) caldo Fraser modificado (MdFB) contendo 20 mg de acriflavina/L a 35°C/48h; b) caldo de enriquecimento para Listeria (LEB) (USDA) a 30°C/48h e c) caldo LEB a 30°C/24h seguido do caldo Fraser modificado (MFB) (USDA) a 35°C/24-48h. No isolamento foram utilizados os ágares cloreto de lítio feniletanol moxalactam (LPM) e Oxford modificado (MOX) e na identificação as provas bioquímicas padrão ou o kit API-Listeria. Os resultados revelaram: i) a viabilidade do emprego do meio MdFB na técnica do NMP; ii) valores de NMP para Listeria sp e L. monocytogenes entre <0,3 a 93/g para peitos e entre <9 a 2,8x103/carcaça ou <0,005 a 1,943/g de frango; iii) predomínio de L. innocua, L. monocytogenes, L. welshimeri e L. seeligeri. Em estudo paralelo com as mesmas amostras, verificou-se ocorrência elevada de Listeria sp e L. monocytogenes, com índices de 96,7% e 90,0% respectivamente e pequena diferença entre carcaças e peitos de frango. O ágar LPM apresentou desempenho melhor que o MOX no isolamento de L. monocytogenes. Em outro estudo, empregando-se a técnica do NMP proposta, verificou-se a ineficiência de hipoclorito de sódio e de fosfato trissódico na redução de L. monocytogenes em coxas de frango artificialmente contaminadas; os níveis de redução obtidos foram ? 0,42 ciclos log, os quais não foram considerados estatisticamente significantesAbstract: L. monocytogenes is currently considered to be an important food pathogen, since various outbreaks and cases of listeriosis have been related to the consumption of foods, including some chicken products. The increase in the production of fowl meats in Brazil, the reduction of the price on the internal market and consequent increase in consumption by the population and the lack of official methods for the quantification of L. monocytogenes in foods, principally in raw foods, are the factors which led to the development of this project, aimed at quantifying the problem and subsequently proposing maximum tolerance limits. Thus refrigerated samples of chicken breast and whole chickens, ali obtained on the retail market, were quantified for Listeria spp by the Most Probable Number (MPN) method, using a) modified Fraser broth (MdFB) containing 20 mg acriflavine/L at 35°C/48h; b) Listeria enrichment broth (LEB) (USDA) at 30°C/48h and c) LEB broth at 30°C/24h followed by modified Fraser broth (MFB) (USDA) at 35°C/24­48h. For the isolation procedure, lithium chloride phenylethanol moxalactam agar (LPM) and modified Oxford agar (MOX) were used, and the standard biochemical test or API­ Listeria kit used for identification. The results showed the following: i) the viability of using the medium MdFB in the MPN technique; ii) MPN values for Listeria spp and L. monocytogenes between <0.3 and 93/g for breasts and between <9 and 2.8x103/carcass or <0.005 to 1.943/g chicken and iii) predominance of L. innocuti, L. monocytogenes, L. welshimeri and L. seeligeri. In a parallel study with the same samples, an elevated occurrence of Listeria spp and L. monocytogenes was determined, with indices of 96.7% and 90.0% respectively, the difference between the carcasses and breasts being relatively small. LPM agar was shown to be a better isolation media for L. monocytogenes than MOX. In another study using the proposed MPN technique, the inefficiency of sodium hypochlorite and of trisodium phosphate in the reduction of L. monocytogenes in artificially contaminated chicken legs was shown, the reduction levels being ?0.42 log cycles, and not therefore statistically significantMestradoMestre em Tecnologia de Alimento

    Biofilms Of Enterococcus Faecalis And Enterococcus Faecium Isolated From The Processing Of Ricotta And The Control Of These Pathogens Through Cleaning And Sanitization Procedures.

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    The biofilm formation of Enterococcus faecalis and Enterococcus faecium isolated from the processing of ricotta on stainless steel coupons was evaluated, and the effect of cleaning and sanitization procedures in the control of these biofilms was determined. The formation of biofilms was observed while varying the incubation temperature (7, 25 and 39°C) and time (0, 1, 2, 4, 6 and 8days). At 7°C, the counts of E. faecalis and E. faecium were below 2log10CFU/cm(2). For the temperatures of 25 and 39°C, after 1day, the counts of E. faecalis and E. faecium were 5.75 and 6.07log10CFU/cm(2), respectively, which is characteristic of biofilm formation. The tested sanitation procedures a) acid-anionic tensioactive cleaning, b) anionic tensioactive cleaning+sanitizer and c) acid-anionic tensioactive cleaning+sanitizer were effective in removing the biofilms, reducing the counts to levels below 0.4log10CFU/cm(2). The sanitizer biguanide was the least effective, and peracetic acid was the most effective. These studies revealed the ability of enterococci to form biofilms and the importance of the cleaning step and the type of sanitizer used in sanitation processes for the effective removal of biofilms.20097-10

    Behavior Of Listeria Monocytogenes In A Multi-species Biofilm With Enterococcus Faecalis And Enterococcus Faecium And Control Through Sanitation Procedures.

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    The formation of mono-species biofilm (Listeria monocytogenes) and multi-species biofilms (Enterococcus faecium, Enterococcus faecalis, and L. monocytogenes) was evaluated. In addition, the effectiveness of sanitation procedures for the control of the multi-species biofilm also was evaluated. The biofilms were grown on stainless steel coupons at various incubation temperatures (7, 25 and 39°C) and contact times (0, 1, 2, 4, 6 and 8days). In all tests, at 7°C, the microbial counts were below 0.4 log CFU/cm(2) and not characteristic of biofilms. In mono-species biofilm, the counts of L. monocytogenes after 8days of contact were 4.1 and 2.8 log CFU/cm(2) at 25 and 39°C, respectively. In the multi-species biofilms, Enterococcus spp. were present at counts of 8 log CFU/cm(2) at 25 and 39°C after 8days of contact. However, the L. monocytogenes in multi-species biofilms was significantly affected by the presence of Enterococcus spp. and by temperature. At 25°C, the growth of L. monocytogenes biofilms was favored in multi-species cultures, with counts above 6 log CFU/cm(2) after 8days of contact. In contrast, at 39°C, a negative effect was observed for L. monocytogenes biofilm growth in mixed cultures, with a significant reduction in counts over time and values below 0.4 log CFU/cm(2) starting at day 4. Anionic tensioactive cleaning complemented with another procedure (acid cleaning, disinfection or acid cleaning+disinfection) eliminated the multi-species biofilms under all conditions tested (counts of all micro-organisms<0.4 log CFU/cm(2)). Peracetic acid was the most effective disinfectant, eliminating the multi-species biofilms under all tested conditions (counts of the all microorganisms <0.4 log CFU/cm(2)). In contrast, biguanide was the least effective disinfectant, failing to eliminate biofilms under all the test conditions.2005-1

    Behavior of listeria monocytogenes in a multi-species biofilm with enterococcus faecalis and enterococcus faecium and control through sanitation procedures

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    The formation of mono-species biofilm (Listeria monocytogenes) and multi-species biofilms (Enterococcus faecium, Enterococcus faecalis, and L. monocytogenes) was evaluated. In addition, the effectiveness of sanitation procedures for the control of the multi-species biofilm also was evaluated. The biofilms were grown on stainless steel coupons at various incubation temperatures (7, 25 and 39 °C) and contact times (0, 1, 2, 4, 6 and 8 days). In all tests, at 7 °C, the microbial counts were below 0.4 log CFU/cm2 and not characteristic of biofilms. In mono-species biofilm, the counts of L. monocytogenes after 8 days of contact were 4.1 and 2.8 log CFU/cm2 at 25 and 39 °C, respectively. In the multi-species biofilms, Enterococcus spp. were present at counts of 8 log CFU/cm2 at 25 and 39 °C after 8 days of contact. However, the L. monocytogenes in multi-species biofilms was significantly affected by the presence of Enterococcus spp. and by temperature. At 25 °C, the growth of L. monocytogenes biofilms was favored in multi-species cultures, with counts above 6 log CFU/cm2 after 8 days of contact. In contrast, at 39 °C, a negative effect was observed for L. monocytogenes biofilm growth in mixed cultures, with a significant reduction in counts over time and values below 0.4 log CFU/cm2 starting at day 4. Anionic tensioactive cleaning complemented with another procedure (acid cleaning, disinfection or acid cleaning + disinfection) eliminated the multi-species biofilms under all conditions tested (counts of all micro-organisms < 0.4 log CFU/cm2). Peracetic acid was the most effective disinfectant, eliminating the multi-species biofilms under all tested conditions (counts of the all microorganisms < 0.4 log CFU/cm2). In contrast, biguanide was the least effective disinfectant, failing to eliminate biofilms under all the test conditions200512FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULO - FAPESP2010/10507-

    Biofilm formation on stainless steel as a function of time and temperature and control through sanitizers

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    Enterococcus spp. contamination was screened from a Minas Frescal cheese processing line. Biofilm formation of Enterococcus faecium and Enterococcus faecalis isolates was evaluated and the effect of sanitization procedures in the control of these biofilms was investigated. Enterococcus spp. were detected in raw milk, milk machine, door handle, floor, drain, thermometer, and Minas Frescal cheese. Biofilm formation on stainless steel was modelled as a function of time (0, 1.2, 4, 6.8, and 8 days) and temperature (7, 13, 27, 41, and 47 °C) using response surface methodology. The model showed that E. faecium biofilms were formed from 1 to 8 days at 12–47 °C, while E. faecalis biofilms were formed from 1 to 8 days at 10–43 °C. None of the sanitizers (sodium hypochlorite 100 mg L−1, peracetic acid 300 mg L−1, and chlorhexidine digluconate 400 mg L−1) was able to completely eliminate the biofilms68916CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNPQ140334/2009-
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