Microcalorimetric growth behavior of E. coli ATCC 25922 in an MCDSC.

Isothermal microcalorimetry can provide a general analytical tool for the characterization of bacterial growth. Methodologies and equipment have been studied to expand the application and disseminate the use of the technique. The MCDSC is a microcalorimeter capable of measuring in the range of 0.2 µW that can operate at a temperature range of -20 to 140 °C or under isothermal conditions. Here, we present the first investigation of MCDSC for E. coli growth with the Baranyi and Roberts modeling application. This study presented the calorimetric E. coli fingerprint at MCDSC and compares it with the plate count technique, giving the data more biological meaning. The calorimeter was able to accurately detect growth metabolism and discriminate E. coli at different inoculum densities. Additionally, the MCDSC can offer a new point of view for evaluating microbial growth, such as the significant reduction in error due to dispersed data by the viable counting method.

Qualidade higiênico-sanitária de saladas de frutas vendidas em quiosques de praias em Florianópolis - SC durante a temporada de verão de 2015 / Hygienic and sanitary qualities of fruit salads sold at beachkiosks in Florianopolis - SC during the 2015 summer season

Nos últimos anos, o estilo de vida tem trazido mudanças na alimentação da população, com o aumento de refeições feitas fora do domicílio, da procura pela praticidade de alimentos prontos e também da busca por uma alimentação mais saudável. O controle da produção e comercialização desses produtos deve ser rigoroso para proteger a saúde da população. Nas praias, observa-se que a estrutura dos quiosques não é adequada para a manipulação de certos alimentos, por isso a venda de salada de frutas não é permitida nas praias de Florianópolis - SC, apesar de ser amplamente comercializada. O objetivo deste trabalho foi de avaliar a qualidade higiênico-sanitária, quanto à presença de Salmonella e à enumeração de coliformes termotolerantes, em 40 amostras de saladas de frutas comercializadas em quiosques de quatro praias de Florianópolis. Os resultados foram comparados com os padrões estabelecidos pela RDC nº 12/01. Somente 5 % das amostras estavam impróprias para o consumo humano por extrapolarem o limite de coliformes termotolerantes. Todas as amostras apresentaram ausência de Salmonella em 25 g. O resultado microbiológico satisfatório da maioria das amostras pode estar associado às condições intrínsecas da salada de frutas, que possui pH baixo o suficiente para inibir o crescimento dos micro-organismos pesquisados.

Recently, changes in lifestyle have modified the eating habits, with an increase in having mealsoutside of home and demanding for the convenience of ready-to-eat foods, and also risingthe search for healthier diet. Controls on this kind of food production and commercializationshould be strict for protecting the population health. Beach kiosks do not offer the suitableconditions for handling certain foods due to their lack of structure. Therefore, it is prohibited to sellfruit salads on the beaches of Florianopolis-SC, although they have been amply commercialized.Hygiene and sanitation conditions were evaluated in 40 fruit salad samples sold in kiosks on thefour beaches in Florianopolis, by analyzing the occurrence of Salmonella and thermotolerantcoliforms counting. These results were compared to the standards established by the localregulation (RDC 12/01). Only 5 % of the samples were considered unsuitable for humanconsumption, as they exceeded the limits established for thermotolerant coliform. All of the samplesshowed negative results for Salmonella in 25 g of food. The satisfactory microbiological resultsfound in this study might be associated with the intrinsic characteristics of fruit salads, which possessa low pH value and being enough to inhibit the growth of these two microorganisms.

Qualidade higiênico-sanitária de saladas de frutas vendidas em quiosques de praias em Florianópolis - SC durante a temporada de verão de 2015 / Hygienic and sanitary qualities of fruit salads sold at beach kiosks in Florianopolis - SC during the 2015 summer season

Nos últimos anos, o estilo de vida tem trazido mudanças na alimentação da população, com o aumento de refeições feitas fora do domicílio, da procura pela praticidade de alimentos prontos e também da busca por uma alimentação mais saudável. O controle da produção e comercialização desses produtos deve ser rigoroso para proteger a saúde da população. Nas praias, observa-se que a estrutura dos quiosques não é adequada para a manipulação de certos alimentos, por isso a venda de salada de frutas não é permitida nas praias de Florianópolis - SC, apesar de ser amplamente comercializada. O objetivo deste trabalho foi de avaliar a qualidade higiênico-sanitária, quanto à presença de Salmonella e à enumeração de coliformes termotolerantes, em 40 amostras de saladas de frutas comercializadas em quiosques de quatro praias de Florianópolis. Os resultados foram comparados com os padrões estabelecidos pela RDC nº 12/01. Somente 5 % das amostras estavam impróprias para o consumo humano por extrapolarem o limite de coliformes termotolerantes. Todas as amostras apresentaram ausência de Salmonella em 25 g. O resultado microbiológico satisfatório da maioria das amostras pode estar associado às condições intrínsecas da salada de frutas, que possui pH baixo o suficiente para inibir o crescimento dos micro-organismos pesquisados.

Recently, changes in lifestyle have modified the eating habits, with an increase in having meals outside of home and demanding for the convenience of ready-to-eat foods, and also rising the search for healthier diet. Controls on this kind of food production and commercialization should be strict for protecting the population health. Beach kiosks do not offer the suitable conditions for handling certain foods due to their lack of structure. Therefore, it is prohibited to sell fruit salads on the beaches of Florianopolis-SC, although they have been amply commercialized. Hygiene and sanitation conditions were evaluated in 40 fruit salad samples sold in kiosks on the four beaches in Florianopolis, by analyzing the occurrence of Salmonella and thermotolerant coliforms counting. These results were compared to the standards established by the local regulation (RDC 12/01). Only 5 % of the samples were considered unsuitable for human consumption, as they exceeded the limits established for thermotolerant coliform. All of the samples showed negative results for Salmonella in 25 g of food. The satisfactory microbiological results found in this study might be associated with the intrinsic characteristics of fruit salads, which possess a low pH value and being enough to inhibit the growth of these two microorganisms.

Validation of HPLC and CE methods for determination of organic acids in sour cassava starch wastewater.

Fast and efficient analytical methods to determine the concentrations of lactic, acetic, propionic and butyric acids in sour cassava starch wastewater using reversed-phase high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), were developed and validated. Good linearity (R(2) > 0.999) and significance with F > 25,000 for all acids was showed. The matrix effect was not detected. The coefficient of variation values indicated good repeatability. The limits of detection (LOD) ranged from 1.0 to 3.7 and 2.0 to 3.0, and the limits of quantification (LOQ) from 3.1 to 12.2, and 8.0 to 12.5mg/L for HPLC and CE, respectively. The quantification of the samples did not reveal significant differences between the methods for all compounds analyzed. However, the benefits of CE in relation to HPLC, such as lower costs and less waste generation, along with shorter analysis times, need to be taken into consideration.

Characterization and genetic variability of Fusarium verticillioides strains isolated from corn and sorghum in Brazil based on fumonisins production, microsatellites, mating type locus, and mating crosses.

Fusarium verticillioides (Gibberella fujikuroi mating population A) is a producer of fumonisins and one of the main contaminants of corn grains. In Brazil, some studies analyzing strains isolated from corn have demonstrated high levels of fumonisins, whereas the levels for strains isolated from sorghum have been found to be low. In the present study, we investigated the genetic diversity of 22 F. verticillioides strains isolated from corn and 21 strains isolated from sorghum cultivated in the State of São Paulo, Brazil. Differences in the genetic profile were observed between the strains isolated from the two substrates using single primer amplification reaction by polymerase chain reaction (SPAR-PCR). Fumonisins levels were higher in strains isolated from corn than in those isolated from sorghum. The MAT-1 and MAT-2 alleles were identified by PCR, and the isolates were subsequently crossed with Fusarium thapsinum (G. fujikuroi mating population F) reference strains because this species is morphologically similar to F. verticillioides and produces low levels of fumonisins. The SPAR haplotypes of some strains isolated from sorghum were similar to the F. thapsinum reference strain haplotypes, but there was no fertile mating between the strains isolated from the two substrates and the F. thapsinum references strains. The MAT-1:MAT-2 proportion was 5:17 and 14:7 for isolates from corn and sorghum, respectively.

Evaluation of viability of Aspergillus flavus and aflatoxins degradation in irradiated samples of maize

Um dos fungos mais importantes atualmente em grãos armazenados é o Aspergillus flavus, o qual produz aflatoxinas. Este fungo pode crescer em diversos substratos e representa uma séria preocupação em saúde pública e nutrição animal. Portanto, o estudo de técnicas que possam ser aplicadas no controle das aflatoxinas é de grande importância. Assim sendo, o objetivo do presente trabalho foi estudar os efeitos da radiação gama no crescimento de Aspergillus flavus Link e na degradação das aflatoxinas B1 e B2, (AFB1 e AFB2) em umidade relativa (UR) de 97-99% e atividade de água (Aa) de 0,88-0,94. Amostras de grãos de milho foram irradiadas, utilizando-se uma fonte de Cobalto 60, emissora de raios gama, com as doses de 2; 5 e 10 kGy. A irradiação foi efetiva na redução do número de Unidades Formadoras de Colônias de A. flavus, por grama, nas amostras de milho analisadas. Adicionalmente, o teste de viabilidade fluorescente (solução de diacetato de fluoresceína e brometo de etídio) revelou diminuição no número de células viáveis com o aumento das doses de irradiação e três diferentes padrões de fluorescência. Além disso, a irradiação induziu a uma parcial redução dos níveis de AFB1 e AFB2, nas doses de 2 e 5 kGy, ao passo que uma completa degradação das aflatoxinas foi observada no ensaio empregado com 10 kGy.