Fate of Escherichia coli O157:H7, Salmonella and Listeria innocua on minimally-processed peaches under different storage conditions

Consumption of fresh-cut produce has sharply increased recently causing an increase of foodborne illnesses associated with these products. As generally, acidic fruits are considered ‘safe’ from a microbiological point of view, the aim of this work was to study the growth and survival of Escherichia coli O157:H7, Salmonella and Listeria innocua on minimally-processed peaches. The three foodborne pathogens population increased more than 2 log₁₀ units on fresh-cut peach when stored at 20 and 25 °C after 48 h. At 10 °C only L. innocua grew more than 1 log₁₀ unit and it was the only pathogen able to grow at 5 °C. Differences in growth occurred between different peach varieties tested, with higher population increases in those varieties with higher pH (‘Royal Glory’ 4.73 ± 0.25 and ‘Diana’ 4.12 ± 0.18). The use of common strategies on extending shelf life of fresh-cut produce, as modified atmosphere packaging and the use of the antioxidant substance, ascorbic acid (2% w/v), did not affect pathogens’ growth at any of the temperatures tested (5 and 25 °C). Minimally-processed peaches have shown to be a good substrate for foodborne pathogens’ growth regardless use of modified atmosphere and ascorbic acid. Therefore, maintaining cold chain and avoiding contamination is highly necessary.     

‘Diffuse skin browning’ in 1‐MCP‐treated apples: etiology and systems of control

BACKGROUND: ‘Diffuse skin browning’ (DSB) is a physiological disorder that affects Golden Delicious apples treated with 1‐methylcyclopropene (1‐MCP). Although a very high incidence is found, very little is known about the etiology of this disorder. This study aims to provide an understanding of the causes of this disorder and prevent it. RESULTS: A very high incidence of DSB was found in 1‐MCP‐treated apples independent of the location of the orchard. Similar to superficial scald, harvest maturity determines the DSB incidence, with the more mature fruit being less sensitive. The 1‐MCP dose (156 nL L^?1 or 625 nL L^?1) and the temperature at which the 1‐MCP treatment was applied (0.5 or 20 °C) did not affect the incidence of DSB. Diphenylamine (DPA) treatment did not prevent DSB, contrary to superficial scald. Additionally, controlled atmosphere storage only partially reduced the incidence of DSB, whereas progressive cooling strategies completely inhibited DSB occurrence. A direct correlation was found between the sensitivity of the Golden Delicious clone to russeting and its sensitivity to develop DSB during storage. CONCLUSION: Our results indicated that DSB and superficial scald are two different disorders involving different oxidative processes. DSB can be prevented by progressive cooling and selection of russeting‐resistant clones. Copyright © 2010 Society of Chemical Industry     

Characterisation of Sierra Morena citrus blossom honey (Citrus sp)

The citrus blossom honey of Sierra Morena (a mountain chain located in the south of Spain) has been characterised by melissopalinological, physicochemical and sensorial analyses with the aim of establishing criteria for a future Protected Designation of Origin, which includes citrus blossom honey as one of the monofloral types produced in that region. Thus, a content in pollen of Citrus sp. ≥5%, Maurizio classes I and II was established, the accompanying pollen spectrum characteristic being that composed by the Myrtus, Echium, Lavandula, Reseda, Quercus, Olea, Crataegus and Cistus pollen types. The physicochemical parameters set were electrical conductivity ≤0.27 mS cm^?1; diastase activity≥ 6 diastase number; colour ≤20 mm Pfund and coordinate CIE‐Lab L = 89.72–95.18, a = ?1.28 to 1.05, b = 16.99–21.79, C = 17–21.82, H = 87.23°–92.01°; hydroximethylfurfural ≤10 mg kg^?1; free acidity ≤28 milliequivalents/litre and moisture ≤18.5%. From the sensorial study, the following profile, based on the evaluation of attributes on a five‐point scale, was obtained: colour white–pale yellow, fluidity (4.22), odour intensity (3.55), citrus blossom aroma/odour intensity (3.6/3.8), sweetness (3.14), acidity (2.36), freshness (61.5%) and persistence (2.9).     

Optimal Selection of Wavelet Coefficients for Electrocardiograph Compression

This paper presents a simple method to implement a complete on‐line portable wireless holter including an electrocardiogram (ECG) monitoring, processing, and communication protocol. The proposed algorithm significantly reduces the hardware resources of threshold estimation for ECG compression, using the standard deviation updated with each new input signal sample. The new method achieves superior performance in terms of hardware complexity, channel occupation and memory requirements, while keeping the ECG quality at a clinically acceptable level.     

Antioxidant activity determines on‐tree maturation in ‘Golden Smoothee’ apples

BACKGROUND: Harvest date clearly determines the postharvest storage behaviour and sensitivity of fruit to physiological disorders. Generally fruit are picked following their maturity indexes but often these indexes poorly represent the physiological state of the fruit. With this in mind, this work aimed to determine a biochemical marker capable of predicting on‐tree maturation in ‘Golden Smoothee’ apples. Changes in the non‐enzymatic and in enzymatic antioxidant potential of fruit were assessed for different harvest dates. RESULTS: Significant differences in antioxidant levels, especially ascorbate and catalase, were found. These changes were related to climatic variations, especially relating to temperature, that appeared to determine the capability of the fruit to produce ethylene. Fruit exposed to higher temperature produced less ethylene and exhibited a significant delay in the induction of their climacteric. In both seasons, changes in quality parameters during on‐tree ripening were not related to the capability of the fruit to produce ethylene, but rather to endogenous levels of antioxidants, especially catalase and ascorbate, at the earliest picking date. CONCLUSION: We hypothesize that ascorbate and antioxidant activity play a role in changes in maturity patterns exhibited by apples in orchards. Both parameters appear to be interesting markers to follow these changes. Copyright © 2009 Society of Chemical Industry     

Estimation of dry matter content in leaves using normalized indexes and PROSPECT model inversion

This work applies remote sensing techniques to estimate dry matter (DM) content in tree leaves. Two methods were used to estimate DM content: a normalized index obtained from the radiative transfer model (RTM) leaf optical properties spectra (PROSPECT) in direct mode and the inversion of the PROSPECT model. The data were obtained from the Leaf Optical Properties Experiment 93 (LOPEX93) database, and only 11 species were used in this study. The species selection was based mainly on the availability of data on fresh and dry samples. The estimation of DM content was obtained from an exponential function that correlated the values of the index proposed, (R₂₃₀₅???R₁₄₉₅)/(R₂₃₀₅?+?R₁₄₉₅), against the DM content of fresh and dry leaf samples. The determination coefficient obtained (r ²?=?0.672) was higher than the coefficient obtained from the inversion of the PROSPECT model (r ²?=?0.507). The data set used to validate the normalized index was provided by the Accelerated Canopy Chemistry Program (ACCP). The determination coefficient between the values obtained from ACCP data and the values estimated for the normalized index was r ²?=?0.767.     

Heuristic Modelling of the Water Resources Management in the Guadalquivir River Basin, Southern Spain

A model comprising blocks of artificial neural networks (ANNs) combined in sequence was used to simulate the inflow and outflow in a water resources system under a shortage of water. We assessed the selection of appropriate input data using linear and non-linear cross-correlation functions and sensitivity analysis. The potential model inputs were flow, precipitation and temperature data from various gauging stations throughout the upper watershed of the ‘Guadiana Menor’ River (southern Spain), and the model considered various input time lags. The ANNs based on the selected inputs were effective relative to those with no relevant inputs, and produced more parsimonious models. We also investigated conceptual analogies inherent in the ANN models by analyzing the response profiles of the modelled variables (inflow and outflow) in relation to each of the selected input data. The results demonstrate that the neural approach approximated the behaviour of various components of the water resources system in terms of various hydrologic cycle processes and management rules. Our findings suggest that in dry periods a mean temperature increase of 1°C in low altitude locations of the region will result in a mean decrease of approximately 2% in the inflow to the water resources system, and a mean increase of approximately 12% in the outflow requirements for irrigation purposes.     

On Strong Stability Preserving Time Discretization Methods

Over the last few years, great effort has been made to develop high order strong stability preserving (SSP) Runge–Kutta methods. These methods have a nonlinear stability property that makes them suitable for the time integration of ODEs that arise from a method of lines approximation of hyperbolic conservation laws. Basically, this stability property is a monotonicity property for the internal stages and the numerical solution. Recently Ferracina and Spijker have established a link between stepsize restrictions for monotonicity and the already known stepsize restrictions for contractivity. Hence the extensive research on contractivity can be transferred to the SSP context. In this paper we consider monotonicity issues for arbitrary norms and linear and nonlinear problems. We collect and review some known results and relate them with the ones obtained in the SSP context.     

Biological structure determination by EM is well suited to grid computing

Conclusion  This short note describes a potential application of grid computing in life sciences: high resolution structure determination of biological specimens by electron microscope tomography. It is shown there are excellent opportunities to benefit from grids: potential intensive applications to exploit the “high-throughput” and the “distributed supercomputing” capabilities of grids. Furthermore, grids may turn into reality solving problems not dared so far, such as structure determination of large viruses at near-atomic resolution or reconstruction of whole cells at molecular resolution. Grid computing will make it possible to afford those “grand challenge” applications currently unapproachable.     

Pathogenesis of Penile Squamous Cell Carcinoma: Molecular Update and Systematic Review

Penile squamous cell carcinoma (PSCC) is a rare but aggressive neoplasm with dual pathogenesis (human papillomavirus (HPV)-associated and HPV-independent). The development of targeted treatment is hindered by poor knowledge of the molecular landscape of PSCC. We performed a thorough review of genetic alterations of PSCC focused on somatic mutations and/or copy number alterations. A total of seven articles have been identified which, overall, include 268 PSCC. However, the series are heterogeneous regarding methodologies employed for DNA sequencing and HPV detection together with HPV prevalence, and include, in general, a limited number of cases, which results in markedly different findings. Reported top-ranked mutations involve TP53, CDKN2A, FAT1, NOTCH-1 and PIK3CA. Numerical alterations involve gains in MYC and EGFR, as well as amplifications in HPV integration loci. A few genes including TP53, CDKN2A, PIK3CA and CCND1 harbor both somatic mutations and copy number alterations. Notch, RTK-RAS and Hippo pathways are frequently deregulated. Nevertheless, the relevance of the identified alterations, their role in signaling pathways or their association with HPV status remain elusive. Combined targeting of different pathways might represent a valid therapeutic approach in PSCC. This work calls for large-scale sequencing studies with robust HPV testing to improve the genomic understanding of PSCC.