ABSTRACT
Minimally processed strawberries have high acceptability but a short shelf life. The application of edible coatings with essential oils may be an alternative to preserve these fruits. Our objective was to develop, apply and characterize the effect of bioactive edible coatings based on agar or sodium alginate with thyme and/or sweet orange essential oils with antimicrobial properties, mainly against Listeria monocytogenes, for strawberries. The effect of the coatings on the physicochemical, microbiological, and sensory properties that determine the shelf life of strawberries was verified at 1, 8, and 15 days. The effect against Listeria monocytogenes bacteria in strawberries artificially contaminated with this microorganism was also evaluated. Thyme and sweet orange essential oils had thymol and D-limonene, respectively, as main components. Alginate coating with sweet orange and thyme essential oil showed the best results. For Listeria monocytogenes, the coating applied after fruit contamination had an antimicrobial effect.
Las fresas mínimamente procesadas tienen una alta aceptación, pero una vida útil corta. La aplicación de recubrimientos comestibles con aceites esenciales puede ser una alternativa para conservar estos frutos. El objetivo fue desarrollar, aplicar y caracterizar el efecto del uso de recubrimientos comestibles bioactivos, a base de agar agar o alginato de sodio, adicionados con aceites esenciales de tomillo y/o naranja dulce, con propiedades antimicrobianas, principalmente anti-Listeria monocytogenes sobre la fresa. Se verificó el efecto de los recubrimientos sobre las características fisicoquímicas, microbiológicas y sensoriales que determinan la vida útil de las fresas a 1, 8 y 15 días. También se evaluó el efecto contra la bacteria Listeria monocytogenes en fresas contaminadas artificialmente con este microorganismo. Los aceites esenciales de tomillo y naranja dulce presentaron timol y D-limoneno como compuestos mayoritarios, respectivamente. El recubrimiento de alginato con aceite esencial de naranja dulce y tomillo mostró los mejores resultados. Para Listeria monocytogenes, el recubrimiento aplicado después de la contaminación de la fruta tuvo un efecto antimicrobiano.
ABSTRACT
ABSTRACT This study aimed to evaluate the microbiological, physicochemical and fatty acid profile of the of "Tambica" (Oligosarcus robustus) raw fish meat and develop and characterize a fish burger. The fish burger was subjected to a sensory analysis. The raw fish meat showed a high content of moisture (82.3%) and minerals (3.1%), a low content of fat (1.5%) and a considerable protein content (13.1%). The raw fish showed a high count of positive coagulase Staphylococcus. Tambica lipid fraction was composed of 41.9% unsaturated and 58.2% saturated fatty acids. Palmitic acid and oleic acid were the major fatty acids in the raw meat fish. The fish burger was well accepted by sensory analysis.
RESUMEN Este estudio tuvo como objetivo evaluar el perfil microbiológico, fisicoquímico y de ácidos grasos de la carne de pescado cruda "Tambica" (Oligosarcus robustus); y desarrollar y caracterizar una hamburguesa de pescado. La hamburguesa de pescado fue sometida a análisis sensorial. La carne de pescado cruda mostró un alto contenido de humedad (82,3%) y minerales (3,1%), bajo contenido de grasa (1,5%) y un contenido de proteína considerable (13,1%). El pescado crudo mostró un recuento alto de Staphylococcus coagulasa positivo. La fracción lipídica de Tambica estaba compuesta por un 41,9% de ácidos grasos insaturados y 58,2% de ácidos grasos saturados. El ácido palmítico y el ácido oleico fueron los principales ácidos grasos en el pescado de carne cruda. La hamburguesa de pescado fue bien aceptada por el análisis sensorial.
Subject(s)
Animals , Fatty Acids , Meat Proteins , Meat , Staphylococcus , Microbiological Techniques , Fish ProductsABSTRACT
Staphylococcus aureus is the second most important pathogen involved in foodborne outbreaks in Brazil. Because of their widespread distribution and biofilm forming ability, handmade sweets are easily contaminated with S. aureus. The aim of this study was to isolate and identify coagulase-positive staphylococci (CPS) from handmade sweets produced in Pelotas City/Brazil. The virulence potential was checked by evaluating the presence of the staphylococcal enterotoxin genes, icaA and icaD genes, the biofilm forming potential and antimicrobial resistance of the isolates. It was find just S. aureus among the CPS isolates. All the S. aureus isolates had biofilm forming ability on stainless steel and more than half of them on polystyrene surfaces. The majority of the isolates carried the icaA (66.6%) and icaD (58.4%) genes and some of them had the genes encoding enterotoxins A (33.4%) and B (16.6%). Furthermore, the majority of the isolates (83%) were resistant to at least one of the tested antimicrobials and multidrug resistance was observed in 8.4% of the isolates. The isolates had virulence potential, and half of them were enterotoxigenic. In addition, the ability of all the isolates to produce biofilms highlights the danger posed by these potentially virulent microorganisms persisting in food manufacturing environments.
