Anticuerpos séricos contra la enfermedad de Newcastle e Influenza Aviar en aves rapaces de Chile.

Objetivo. Detectar la presencia de anticuerpos séricos sanguíneos contra los virus de la Enfermedad de Newcastle (ENC) e Influenza aviar (IA), para comprender la contribución de las aves silvestres en la transmisión de estos virus en Chile. Materiales y métodos. Se analizaron 63 aves pertenecientes a los órdenes Falconiformes y Strigiformes desde centros de rehabilitación de aves de las zonas central y sur de Chile. Se realizaron las pruebas de inhibición de la hemoaglutinación (IHA) para detectar anticuerpos contra el virus ENC e inmunodifusión en gel agar (IDGA) y ELISA para IA. Resultados. Se detectaron 14 aves positivas (22.2%) para anticuerpos séricos contra el virus de la ENC. En cambio, no se registraron anticuerpos séricos sanguíneos para el virus de la IA. Conclusiones. La presencia de aves rapaces positivas en los centros de rescate a los anticuerpos séricos contra el virus de la ENC puede ser explicada por el consumo de carne de pollos que han sido vacunados contra ENC o consumo de aves que han adquirido directamente el virus vacunal a través de los distintos procedimientos de administración (aerosoles, bebederos) de la vacuna o por el ingreso a los centros de rescate de aves rapaces migratorias, las que podrían facilitar la diseminación de la infección desde los países de origen, hecho que debe ser investigado

Probiotics in fermented meat products

Several scientific reports suggest a positive correlation between the administration of certain microorganisms generally regarded as safe (GRAS) with health benefits. Microorganisms displaying these health properties are widely known as probiotics, which have been defined by FAO and WHO (2002) as “live microorganisms that, when administered in an adequate amount, confer a health benefit on the host”. The administration of probiotics could be done through either, the direct ingestion of the probiotic cultures or through food products which could act as a carrier for these microorganisms

Evaluation of the PLA-nZH-Cu Nanocomposite Film on the Micro-Biological, Organoleptic and Physicochemical Qualities of Packed Chicken Meat

This research evaluated the contribution of nanocomposite films based on different concentrations of nZH-Cu (1%, 2%, and 3%) to the microbiological, organoleptic, and physicochemical characteristics of packed chicken breast meat. Analysis of some meat quality traits, such as microbiological, chemical, and physical, were conducted on a laboratory scale. For this, small squares of chicken breast meat, weighing approximately 10 g, were aseptically wrapped with rectangular pieces of 5 × 10 cm PLA-nZH-Cu nanocomposite films, which were stored at 4 °C for 20 days. The microbiological results indicated efficient antibacterial activity (at any nZH-Cu concentration in the nanocomposite films) on the total viable count of groups of psychrophiles, aerobic mesophiles, Enterobacteriaceae, and Salmonella spp. until day 10 of storage (p p < 0.05). The analysis of the experimental tests carried out determined that the PLA-nZH-Cu nanocomposite films played an effective role in the bacterial safety of the packaged chicken. It was concluded that the nZH-Cu nanocomposite films, at all concentrations tested, extended the shelf life of the chicken breast meat for up to 10 days in a refrigerator at 4 °C

Cronobacter sakazakii and microbiological parameters in dairy formulas associated with a food alert in Chile

The objective of this study was to evaluate the presence of Cronobacter sakazakii and microbiological parameters in dairy products associated with a food alert. Ninety dairy product samples were analyzed, including seven commercial brands and two product types (liquid and powdered) from four countries. Aerobic plate count (APC) and Enterobacteriaceae count were performed according to Chilean standards. Cronobacter spp. and C. sakazakii were identified by polymerase chain reaction real time amplification of rpoB and cgcA genes and the genotype by multilocus sequence typing. Eighty-eight percent of dairy products showed APC higher than the detection limit. Fifty percent of liquid commercial brand samples contained APC: 2.6, 2.3, 1.1, and 2.9 CFU/mL in brands A, C, E, and G, respectively. Results for powdered commercial brands were 3.0, 3.6, and 5.7 CFU/g in brands B, D, and F, respectively. Maximum count (5.7 CFU/g) occurred in brand F dairy product manufactured in Chile. Enterobacteriaceae were found in 55% of the samples, 64% in liquid and 51% in powdered commercial brands. In 50% of brands B, D, and E, samples contained 2.9, 2.8, and 2.7 log CFU/g, respectively. Only liquid commercial brands from the United States had Enterobacteriaceae values between 0.1 and 4.5 CFU/mL. Seventeen suspicious strains were isolated and nine were identified as Enterobacter spp. Only eight suspicious strains from four powdered commercial brands (Chile and Singapore) were confirmed as C. sakazakii by rpoB and cgcA gene amplification and fusA sequencing. C. sakazakii prevalence in the analyzed samples was 8.8%. There were 11% of powdered milk brands that contained APC between 4.0 and 4.7 log CFU/g and 55% of the samples contained Enterobacteriaceae. C. sakazakii was found in dairy products manufactured in Chile and Singapore. On the basis of this information, the Chilean Ministry of Health (RSA) decreed a national and international food alert and recalled all the product batches that resulted positive in the present study from supermarkets and pharmacies.Research Directorate of the Universidad del Bio-Bio 161720 3/R 091824/R GI 171220/E

Nanocoatings of Bovine Serum Albumin on Glass: Effects of pH and Temperature

Protein adsorption is influenced by many factors such as temperature, pH, protein size and structure, or surface energy and roughness, among others. Self-assembled monolayers (SAMs) and the Langmuir-Blodgett (LB) technique are two of the techniques more used to produces ultrathin films of proteins on surfaces. In this work, we established protocols for the preparation of nanocoatings of bovine serum albumin (BSA) protein on glass surface using SAMs and LB. Furthermore, we determined how small changes in temperature and pH can affect the covering when SAMs are used. Using a combination of different analyses, such as relative roughness, dynamic contact angles, and atomic force microscopy (AFM), it was possible to establish conditions to obtain a uniform nanocoating using SAMs. The results of the analysis of the nanocoating performed using the LB technique were very similar to those obtained using SAMs. The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory in conjunction with the AFM images showed that electrostatic interactions are very important in the self-assembly process, but a process dominated solely by attraction is not sufficient to achieve a good SAM nanocoating, since it does not allow proper orientation and packaging of BSA molecules on the glass surface.Universidad del Bio-Bio 191520 4/R GI 152322/EF GI 195420 E/F ANID/FONDAP/1513001