The antimicrobial activity of essential oils on Clostridium perfringens type A and the influence of such oils on mortadella quality were assessed. The anticlostridial effects of several essential oils and their combinations were identified and some essential oils and their combinations were selected for further study in mortadellas supplemented with 75 ppm sodium nitrite and inoculated with C. perfringens. The growth of C. perfringens in mortadella was not inhibited by nitrite (control treatments of 75 and 150 ppm), but the essential oils presented a significant inhibitory effect. The essential oil of Origanum vulgare presented the highest anticlostridial activity. Moreover, higher concentrations of residual nitrite were found in mortadellas containing essential oils than in controls. PRACTICAL APPLICATIONSClostridium perfringens is an anaerobic bacteria, gram-positive and with the ability to form spores that are highly resistant to environmental conditions and causes two important human illnesses: a relatively mild, classic type A diarrhea and the more serious type C human necrotic enteritis. Approximately 75% of cases of illness due to C. perfringens are attributed to meat, meat products and poultry. Nitrite and nitrate salts are added to cooked meat products to control the growth of sporulated bacteria, however, such salts can react with amines to form N-nitrous compounds, particularly nitrosamines, which are mutagenic, neurotoxic, nephrotoxic and carcinogenic. The natural compounds with antimicrobial activity can be used to reduce them. As high concentration of essential oils may negatively affect the flavor of foods, several combinations of essential oils should be minimized to the concentration required. The growth of C. perfringens in mortadella was not inhibited by nitrite, but the essential oils presented a significant anticlostridial activity shown to be possible to use.

RESUMO:Este trabalho teve por objetivo avaliar o efeito bactericida in vitro de dezesseis óleos essenciais sobre Escherichia coli enterotoxigênica (ETEC). Dentre os óleos essenciais estudados, três foram extraídos in situ por arraste a vapor e treze foram adquiridos comercialmente. Todos os óleos foram analisados por CG-EM e CG-DIC. A atividade bactericida foi avaliada pelo método de microdiluição utilizando-se caldo triptona de soja e microplacas de poliestireno de 96 poços, com posterior plaqueamento das culturas em ágar triptona de soja. Os óleos essenciais de Cinnamomum cassia e de Thymus vulgaris apresentaram concentração mínima bactericida (CMB) de 0,12% e 0,25%, respectivamente. Já os óleos comerciais de Syzygium aromaticum e Origanum vulgare apresentaram ambos CMB de 0,50% e os óleos extraídos in situ de Cymbopogon citratus e Origanum vulgare apresentaram ambos CMB de 1,00%. Os dezesseis óleos essenciais apresentaram composição química qualitativa e quantitativa distintas. As análises químicas dos óleos essenciais de Cinnamomum cassia e de Thymus vulgaris tiveram a presença majoritária de E-cinamaldeído (84,52%) e timol (50,89%). Conclui-se que os óleos de C. cassia e T. vulgaris foram os mais eficazes na inibição do crescimento in vitro dessa bactéria, a qual possui diferentes níveis de sensibilidade dependendo da composição química do óleo. Palavras-chave:Patógeno alimentar, ETEC, antimicrobianos naturais, atividade bactericida, cromatografia gasosa.ABSTRACT: Determination of minimum bactericidal concentration of sixteen essential oils on enterotoxigenic Escherichia coli. This study aimed to evaluate the bactericidal effect in vitro of sixteen essential oils on enterotoxigenic Escherichia coli (ETEC). Among the essential oils, three were extracted in situ by steam distillation and thirteen were purchased commercially. All oils were analyzed by GC-MS and GC-FID. The bactericidal activity was evaluated by the microdilution method using tryptone soy broth, and 96-well polystyrene microplates with subsequent plating of the cultures in tryptone soy agar. Cinnamomum cassia and Thymus vulgaris essential oils showed minimal bactericidal concentration (MBC) 0.12% and 0.25%, respectively. Both commercial oils of Syzygium aromaticum and Origanum vulgare showed MBC of 0.50% and the oils extracted in situ Origanum vulgare and Cymbopogon citratus showed both MBC of 1.00%. The sixteen essential oils pointed out distinct qualitative and quantitative chemical composition. Chemical analysis of Cinnamomum cassia and Thymus vulgaris oils had the predominant presence of E-cinnamaldehyde (84.52% ± 0.07%) and thymol (50.89% ± 0.31%). In conclusion, T. vulgaris and C. cassia oils were the most effective in inhibiting in vitro growth of this bacterium, which has different sensitivity levels depending on the chemical composition of the oil.

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Os carotenóides são pigmentos naturais presentes nos alimentos, que dependendo de suas estruturas podem ser convertidos em vitamina A. Representam uma classe de antioxidantes encontrados predominantemente em frutas e vegetais, tendo sua composição e estabilidade nos alimentos afetadas por diversos fatores. O metabolismo dos carotenóides no organismo é um processo complexo, similar ao dos lipídeos e está associado a potenciais benefícios através de sua atividade modulatória. A sua ação, principalmente antioxidante, é dependente da capacidade do organismo absorvê-lo, armazená-lo e utilizá-lo em seus diferentes sistemas metabólicos. Diante disso é necessário compreender os fatores que afetam a sua biodisponibilidade. Portanto, o objetivo desta revisão foi descrever o metabolismo dos carotenóides, sua atividade no organismo e os fatores que podem interferir em sua biodisponibilidade. Palavras chave: Metabolismo; interações nutricionais, atividade modulatória.Carotenoids are natural pigments present in foods, depending on their structures can be converted into vitamin A. Represent a class of antioxidants found mainly in fruits and vegetables, and its composition and stability of foods affected by several factors. The metabolism of carotenoids in the body is a complex process, similar to that of lipids and is associated with potential benefits through their modulatory activity. Their action, especially antioxidant, is dependent on the body's ability to absorb it, store it and use it in their different metabolic systems. Besides, we need to understand the factors affecting its bioavailability. Therefore, the aim of this review was to describe the metabolism of carotenoids, their activity in the body and the factors that may interfere with its bioavailability. Key words: Metabolism, nutritional interactions, modulatory activity.

The effects of additioning essential oil mixtures and reducing the sodium nitrite content (75 ppm) on Clostridium difficile inoculated in mortadellas and on the product’s technological characteristics were evaluated. 15 essential oils were tested preliminarily, but only four were selected. The minimum bactericidal concentrations found were 1.2 % for Ocimum basilicum, 0.3 % for Origanum vulgare and for Thymus vulgaris and 0.15 % for Litsea cubeba. There wasn`t significant difference in viable cell growth between treatments and the control; however, there was an increase in viable cells of approximately 2.5 log10 MPN/g after the fifth day. Combinations of oils didn`t prevent sporulation, however a synergistic effect was observed in vitro. There was a reduction in pH during storage and a greater amount of residual nitrite for the F1 treatment (Origanum vulgare (0.2 %); Thymus vulgaris (0.05 %) and Litsea cubeba (0.025 %), with 10.23 ppm, and reduction of residual nitrite during the storage period from 18.75 ppm on the first day of storage to 5.11 ppm on the last. No significant changes were observed in the technological characteristics of the product with the analyzed treatments.