Development of a Halochromic, Antimicrobial, and Antioxidant Starch-Based Film Containing Phenolic Extract from Jaboticaba Peel.

In this study, the antioxidant, antimicrobial, mechanical, optical, and barrier attributes of Solanum lycocarpum starch bio-based edible films incorporated with a phenolic extract from jaboticaba peel were investigated. Aiming to determine the effect of the polymers and the phenolic extract on the properties of the films, a three-factor simplex-lattice design was employed, and the formulation optimization was based on the produced films' antioxidant potential. The optimized formulation of the starch-PEJP film showed a reddish-pink color with no cracks or bubbles and 91% antioxidant activity against DPPH radical. The optimized starch-PEJP film showed good transparency properties and a potent UV-blocking action, presenting color variation as a function of the pH values. The optimized film was also considerably resistant and highly flexible, showing a water vapor permeability of 3.28 × 10-6 g m-1 h-1 Pa-1. The microbial permeation test and antimicrobial evaluation demonstrated that the optimized starch-PEJP film avoided microbial contamination and was potent in reducing the growth of Escherichia coli, Staphylococcus aureus, and Salmonella spp. In summary, the active starch-PEJP film showed great potential as an environmentally friendly and halochromic material, presenting antioxidant and antimicrobial properties and high UV-protecting activity.

Genotypic and phenotypic detection of capsular polysaccharide and biofilm formation in Staphylococcus aureus isolated from bovine milk collected from Brazilian dairy farms.

Staphylococcus aureus is a pathogen that frequently causes mastitis in bovine herds worldwide. This pathogen produces several virulence factors, including cell-associated adhesins, toxic and cytolytic exoproteins, and capsular polysaccharides. The aim of the present study was to test for the presence of genes involved in capsular polysaccharide production and biofilm formation in S. aureus isolated from bovine mastitis samples collected from 119 dairy herds located in three different Brazilian regions, as well as to assay the production of capsular polysaccharides and biofilm, in vitro. The detection of the cap, icaAD, and bap genes was performed using PCR. The detection and quantification of capsular polysaccharide production was performed using ELISA assays. The ability of the isolates to form a biofilm was examined using the polystyrene surface of microtiter plates. All 159 S. aureus isolates investigated harboured the cap gene: 80 % carried the cap5 gene and 20 % carried the cap8 gene. Sixty-nine percent of the isolates expressed capsular polysaccharide (CP) in vitro, 58 % expressed CP5 and 11 % expressed CP8. All of the isolates harboured the icaA and icaD genes, and 95.6 % of the isolates carried the bap gene. Of the 159 isolates analysed, 97.5 % were biofilm producers. A significant association between the capsular genotype and phenotype and the amount of biofilm formation was detected: cap5/CP5 isolates tended to form more biofilm and to produce a thinner CP layer than cap8/CP8 isolates. The results indicate a high potential for pathogenicity among S. aureus isolated from bovine milk collected from three different regions in Brazil.

Influência da embalagem na vida útil de presuntos fatiados / Packing influence on the shelf life of sliced ham

Visou-se com este trabalho, comparar a vida útil de presunto fatiado sem capa de gordura (condicionadas à temperatura entre -1 e 4°C), usando os tratamentos: sistema de embalagem a vácuo (EV) e sistema de embalagem com atmosfera modificada (AM) (50 por cento de N2 e 50 por cento de O2), com os laminados flexíveis PET/PEBDL (AM1) e PVDC/EVA/PEBDL (AM2) sobre os parâmetros microbiológicos e físico-químicos, por 35 dias. As análises realizadas foram: contagem padrão em placas (CCP), contagem de fungos (CF), pH e umidade. Nas análises do dia inicial de trabalho verificou-se a contagem de <10²UFC/g de Staphylococcus aureus e para os demais microrganismos <10¹UFC/g. Com relação aos tratamentos, verificou-se que a embalagem com AM estendeu em 5 dias a vida útil do produto em relação a embalagem EV. O pH inicial médio de 6,4 aumentou para 6,55; 6,58 e 6,63 nos tratamentos EV, AM1 e AM2, respectivamente. O tratamento AM2 aumentou a vida útil em relação ao AM1.

The aim of this work was to compare the shelf-life of sliced ham without fat layer storage in a range of temperature between 1° and 4°C using the following treatments: vacuum packing (VP) and packing with modified atmosphere (MA) (50 percent of N2 and 50 percent of O2) using flexible sheets of PEAD/LDPE (MA1) and PVDC/EVA/LDPE (MA2) on microbiological and physical chemical parameters for 35 days. Analysis of plate count of microorganisms, pH and humidity were conduced to evaluate the shelf-life of ham. In the first day of analyze the countings of Staphylococcus aureus had been inferior to 10² CFU/g and for the other microorganisms inferior to 10¹ CFU/g. The packed with modified atmosphere increased five days in the shelf-life of the product when compared to vacuum packing. The initial pH (6.4) increased to 6.55, 6.58 and 6.63 on VP MA1 and MA2, respectively. The treatment MA2 increased the shelf-life when compared to modified atmosphere (1).