Evaluation of mutagenicity associated with Escherichia coli inactivation in UV-treated orange juice

UV radiation is an alternative technology for the elimination of pathogenic micro-organisms in liquid food. The objectives of this work were to investigate mutagenesis using the Ames test in : (1) fresh squeezed orange juice submitted to UV radiation doses required to achieve 5 and 10 log10 reductions of different strains of Escherichia coli serotype O157:H7 at two temperatures, and (2) commercial pasteurized orange juice submitted to thermal treatment. Two histidine-auxotrophic strains, Salmonella Typhimurium TA98 and TA97a, were used in the Ames test with and without metabolic activation. In commercial pasteurized orange juices, mutagenesis was not observed with S. Typhimurium TA98 strain with and without metabolic activation, but high mutagenic effect was observed using TA97a with metabolic activation. UV radiation did not affect the stability of ascorbic acid in aqueous solution. However, degradation of ascorbic acid was observed when UV treatment was performed on squeezed orange juice, following first order kinetics. UV treatment required to achieve 5 log10 reductions (1.5 J/cm2) did not show a mutagenic effect with and without metabolic activation using the tested strains, but a higher UV radiation dose necessary to produce 10 log10 reductions (3.0 J/cm2) showed mutagenicity with metabolic activation.Centro de Investigación y Desarrollo en Criotecnología de Alimento

El laberinto, motivo sacramental en Tirso y Calderón

Este trabajo estudia el motivo del laberinto en dos autos sacramentales del siglo XVII: “El laberinto de Creta” de Tirso de Molina y “El laberinto del mundo” de Calderón de la Barca. Se enmarca dentro de un estudio más ambicioso que pretende abarcar la utilización del concepto de laberinto en el teatro del siglo XVII. La lectura de ambos textos muestra profundas transformaciones en el diseño, la estructura, la métrica y la utilización de la alegoría. El estudio comparado arroja una mayor destreza dramática en Calderón, frente a una acusada tendencia a la disgregación estructural en Tirso.The present article analyses the motive of the labyrinth in two “autos sacramentales” of the 17th century: “El laberinto de Creta” by Tirso de Molina and “El laberinto del mundo” by Calderón de la Barca. It is conceived within the framework of a more amplified study with the aim of uncovering the use of the labyrinth as a nuclear concept of 17th century theatre. A lecture of both texts reveals profound transformations with respect to the allegory’s design, structure, metrics, and usage. The comparative study sheds light on a more skillful dramatization by Calderón, whereas in Tirso a structural decomposition is evident

Influence of production on the presence of patulin and ochratoxin A in fruit juices and wines of Argentina

In this study, the relative frequency and concentration of patulin (PAT) and ochratoxin A (OTA) in fruit juices and wines collected in Argentina between 2005 and 2013 were determined by high performance liquid chromatography. PAT was detected in 1997 of 5958 samples (ranging from 3.0 to 19,622 μg/L), and 510 samples presented PAT levels above 50 μg/L. The highest incidence of PAT was observed in 2005 (243 of 419 samples) while the lowest was quantified in 2009 (104 of 482 samples). OTA was detected in only 22 of 1401 samples at concentrations ranging from 0.15 to 3.6 μg/L, and the highest incidence was observed in 2007 (8 of 153 samples). The concentration of PAT and OTA in the beverages analyzed was found to be affected by the type of fruit product, fruit commodity and production year. A great amount of data on the incidence of these mycotoxins in these matrixes can be further used in the development and reinforcement of measures to reduce the burden of their presence in juices and wines. This is important since PAT levels above the limit set by regulations were high and fruit juices are quite consumed by children. Although OTA contamination was low, effective ways to safeguard consumer exposure to PAT and OTA and consequently to protect public health are essential and indispensable.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Criotecnología de Alimento

Development and in-house validation of a real-time polymerase chain reaction for the detection of Listeria monocytogenes in meat

Listeriosis is a foodborne disease caused by Listeria monocytogenes. The aims of this work were to develop and validate an in-house real-time polymerase chain reaction (RT-PCR) for the detection of L. monocytogenes, and to determine its prevalence in raw ground beef samples from 53 butcheries that also sell ready-to-eat foods. One set of primers and one hydrolysis probe were designed for hly gene detection and then challenged with pure strains. The detection was successful for all L. monocytogenes strains analyzed and negative for all non-L. monocytogenes strains (detection limit, 10 colony forming unit [CFU]/mL). Inclusivity, exclusivity, and analytical accuracy were 100%. L. monocytogenes was detected in 41.5% of raw ground beef samples from the 53 butcheries analyzed. This RT-PCR may be a valuable method for rapid detection of L. monocytogenes in meat.Instituto de Genética VeterinariaFacultad de Ciencias Veterinaria

Influence of production on the presence of patulin and ochratoxin A in fruit juices and wines of Argentina

In this study, the relative frequency and concentration of patulin (PAT) and ochratoxin A (OTA) in fruit juices and wines collected in Argentina between 2005 and 2013 were determined by high performance liquid chromatography. PAT was detected in 1997 of 5958 samples (ranging from 3.0 to 19,622 μg/L), and 510 samples presented PAT levels above 50 μg/L. The highest incidence of PAT was observed in 2005 (243 of 419 samples) while the lowest was quantified in 2009 (104 of 482 samples). OTA was detected in only 22 of 1401 samples at concentrations ranging from 0.15 to 3.6 μg/L, and the highest incidence was observed in 2007 (8 of 153 samples). The concentration of PAT and OTA in the beverages analyzed was found to be affected by the type of fruit product, fruit commodity and production year. A great amount of data on the incidence of these mycotoxins in these matrixes can be further used in the development and reinforcement of measures to reduce the burden of their presence in juices and wines. This is important since PAT levels above the limit set by regulations were high and fruit juices are quite consumed by children. Although OTA contamination was low, effective ways to safeguard consumer exposure to PAT and OTA and consequently to protect public health are essential and indispensable.Facultad de Ciencias ExactasCentro de Investigación y Desarrollo en Criotecnología de Alimento

A pan-European epidemiological study reveals honey bee colony survival depends on beekeeper education and disease control

Reports of honey bee population decline has spurred many national efforts to understand the extent of the problem and to identify causative or associated factors. However, our collective understanding of the factors has been hampered by a lack of joined up trans-national effort. Moreover, the impacts of beekeeper knowledge and beekeeping management practices have often been overlooked, despite honey bees being a managed pollinator. Here, we established a standardised active monitoring network for 5 798 apiaries over two consecutive years to quantify honey bee colony mortality across 17 European countries. Our data demonstrate that overwinter losses ranged between 2% and 32%, and that high summer losses were likely to follow high winter losses. Multivariate Poisson regression models revealed that hobbyist beekeepers with small apiaries and little experience in beekeeping had double the winter mortality rate when compared to professional beekeepers. Furthermore, honey bees kept by professional beekeepers never showed signs of disease, unlike apiaries from hobbyist beekeepers that had symptoms of bacterial infection and heavy Varroa infestation. Our data highlight beekeeper background and apicultural practices as major drivers of honey bee colony losses. The benefits of conducting trans-national monitoring schemes and improving beekeeper training are discussed