Perceived barriers for healthy eating by university employees at the workplace

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Comparison of recovery methods for the enumeration of injured Listeria innocua cells under isothermal and non-isothermal treatments

This study compares the feature of different media with the combination of selective with non-selective media in a TAL method for recovery of Listeria innocua cells exposed to thermal treatments. Experiments were conducted in broth at constant temperature (52.5 and 65.0 ºC) and pH (4.5 and 7.5) conditions, using NaCl or glycerol to adjust water activity to 0.95. Four different media were used in bacterial cell enumeration: (i) a non-selective medium e TSAYE, (ii) two selective media e TSAYE þ 5%NaCl and Palcam Agar and (iii) TAL medium (consisting of a layer of Palcam Agar overlaid with one of TSAYE). Two food products were used as case studies aiming at comparison of results obtained on selective and TAL media enumeration. Parsley samples were inoculated with L. innocua and subjected to posterior thermal treatments both under isothermal (52.5, 60.0 and 65.0 ºC) and non-isothermal (heating rate of 1.8 ºC/min from 20.0 to 65.0 ºC) conditions. The recovery capability of TAL method was also studied when a pre-cooked frozen food (i.e. meat pockets) was fried (oil temperature of w180 ºC). TAL method proved to be better than Palcam Agar in terms of capability to recover injured cells and was effective in L. innocua enumeration when non-sterile samples were analysed.info:eu-repo/semantics/acceptedVersio

Thermosonication applied to kiwi juice processing: anti-listerial effect and quality retention

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Effect of convective and freeze-drying processes on galega kale quality

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Thermal and non-thermal Cantaloupe melon juice pasteurization: Assessment of the impact of ozone exposure on microbiological, physicochemical and bioactive characteristics

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Study of the effect of ozone in aqueous solution and chemical agents on strawberry’s safety (fragaria anannassa)

[PORT] O desenvolvimento de tecnologias inovadoras que promovam a segurança de frutos e vegetais, reduzindo o risco de doenças associadas a produtos contaminados, constitui uma preocupação actual. Os tratamentos térmicos, quando convenientemente aplicados, são eficientes na redução da carga microbiana dos frutos e vegetais. Contudo, a temperatura tem um impacto bastante negativo ao nível da textura dos alimentos. Como alternativa podem ser utilizados diversos agentes químicos na lavagem dos hortofrutícolas, tais como soluções de peróxido de hidrogénio e de cloro, de forma a garantir a sua segurança e maior retenção de qualidade. Mais recentemente, a utilização de ozono como agente desinfectante, quer em fase aquosa, quer em fase gasosa, tem vindo a ser objecto de estudo. Com este trabalho pretendeu-se estudar o efeito do ozono em solução aquosa, na redução de mesófilos totais em morango. Os resultados foram comparados com os obtidos por lavagens utilizando dois agentes químicos: soluções de peróxido de hidrogénio (1% e 5% m/m) e soluções de hipoclorito de sódio disponível na forma comercial de Amukina (11.5 g/L). Todos os tratamentos aplicados tiveram a duração de 2 minutos. Os tratamentos com ozono foram combinados com tratamentos térmicos (branqueamentos a 50 ou 55 ºC, durante 1 minuto). Os resultados mostraram que o tratamento não térmico mais eficaz na redução da flora mesófila, foi a lavagem com peróxido de hidrogénio a 5% (redução de cerca de 2 ciclos logarítmicos). Estes resultados não são significativamente diferentes dos resultados obtidos com lavagens com água ozonada (resultados confirmados por ANOVA e testes Post Hoc). O efeito dos tratamentos térmicos, a 50 e 55 ºC, não foi potenciado quando estes foram combinados com lavagens com ozono. Resultados semelhantes foram obtidos quando os tratamentos combinados foram aplicados por ordem alternada (i.e. branqueamento vs ozono ou ozono vs branqueamento). [ENG] The development of innovative technologies, aiming at reducing the risk of related food-borne diseases and thus promoting fruits and vegetables, is an actual concern. Thermal treatments, when conveniently applied, are efficient in microbial load reduction. However, temperature has a negative impact at food textural level. Alternatively, washings with solutions of several chemical agents, such as hydrogen peroxide or sodium hypochlorite, may be applied. More recently, the use of ozone as a disinfectant agent, both in aqueous or in gaseous phases, has been considered. The objective of this work was to study the effect of ozone in aqueous solution, on total mesophyles reduction in strawberries. Results were compared to the ones obtained with washings with two chemical agents: hydrogen peroxide solutions (1% and 5% w/w) and sodium hypochlorite solutions, commercially available as Amukina (11.5 g/L). All treatments were applied for 2 minutes. Ozone treatments were also combined with thermal processes (blanching at 50 or 55 ºC, for 1 minute). Results showed that washings with hydrogen peroxide solutions at 5% were the most efficient non-thermal treatments applied for mesophyles reduction in strawberries (approximately 2 log-cycles). These results were not significantly different from the ones obtained with ozonated-water washings (confirmed by ANOVA and Post Hoc tests). The thermal treatment effect, at 50 and 55 ºC, was not enhanced when combined with ozonatedwater washings. Similar results were obtained when the combined treatments were applied by alternated order (i.e. blanching vs ozono ou ozono vs blanching).Os autores agradecem o apoio financeiro ao Programa Operacional Agricultura e Desenvolvimento Rural – Projecto AGRO nº822 (Novas Tecnologias de Processamento de Hortofrutículas Congelados – EMERCON). Os autores Alexandre E.M.C., Santos-Pedro D.M. e Brandão T.R.S. agradecem ainda à Fundação para a Ciência e a Tecnologia (bolsas de investigação SFRH/BD/16042/2004, SFRH/BPD/9174/2002 e SFRH/BPD/11580/2002, respectivamente)

Efficacy of non-thermal technologies and sanitizer solutions on microbial load reduction and quality retention of strawberries

The effect of non-thermal technologies (ozone in aqueous solution, ultrasound and ultraviolet C radiation) and washings with chemical solutions (sodium hypochlorite and hydrogen peroxide) on safety and quality features of strawberries was studied. These treatments were applied before fruit storage at two different temperatures (4 and 15 C). The overall impact on microbial loads (total mesophiles, and yeasts and moulds) and selected quality attributes (colour, firmness, pH, total anthocyanins and ascorbic acid content) was assessed. During storage under refrigerated temperature, washing with hydrogen peroxide solutions resulted in strawberries with lower microbial loads, when compared to the other treatments. However, it produced significant key quality attributes losses, such as colour and total anthocyanins content. The results presented show that ozone and ultrasound are promising alternatives to thermal treatments. The application of such technologies, before refrigerated storage of strawberries, allowed a satisfactory retention of all quality characteristics analysed, while being efficient in controlling microbial contamination.info:eu-repo/semantics/publishedVersio

Effect of pre-treatments on solar drying kinetics of red seedless grapes (cv. Monukka)

<p>Two different pre-treatments were applied to grapes prior to drying in a mixed mode solar dryer. Grapes were blanched in water and in a 0.1% sunflower oil water emulsion, both at 99^oC and for approximately 15 seconds. Several models were tested to fit the experimental data of drying curves but the normalized Newton model gave the best fit results. Samples blanched in hot water or in the 0.1% edible oil emulsion had faster drying rates than untreated samples. Contrary to what was expected, pre-treating with the 0.1% edible oil emulsion did not increase the drying rate to a higher extent than blanching. Pre-treatments did not give a noteworthy difference in the total drying time. However, they had an important role in accelerating initial drying rates, thus preventing moulds and bacterial growth and consequently increasing farmers’ income.</p

Assessment of the impact of hydrogen peroxide soutions on microbial loads and quality factors of red bell peppers, strawberries and watercress

The impact of sodium hypochlorite and hydrogen peroxide (H2O2 at 1 and 5%) solutions on Listeria innocua in red bell peppers, total mesophiles in strawberries and total coliforms in watercress was studied. Quality attributes such as colour, firmness and pH were studied for all products; total anthocyanins content was determined for strawberries. Sensorial analyses were also carried out for all products. Results showed that H2O2 (5%) provided the highest reductions of microbial loads. Besides H2O2 (1%) had a lower impact, it was more effective than water-washings. Sodium hypochlorite solutions lead to microbial reductions comparable to water risings. In terms of quality, H2O2 (5%) was the solution with higher negative impact on products’ colour. For strawberries, such colour alterations were also detected by sensorial analyses. The anthocyanins content decreased significantly. Overall it was found that H2O2 (1%) was a good sanitizer solution, since microbial reduction was attained while quality factors did not suffer considerable alterations.info:eu-repo/semantics/publishedVersio

Process optimization and shelf-life determination of processed food. Review of same case studies

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