Toward Macroscale,Isotropic Carbons with Graphene‐Sheet‐Like Electrical and Mechanical Properties

Realization of macroscale three‐dimensional isotropic carbons that retain the exceptional electrical and mechanical properties of graphene sheets remains a challenge. Here, a method for fabricating graphene‐derived carbons (GDCs) with isotropic properties approaching those of individual graphene sheets is reported. This synthesis scheme relies on direct cross‐linking of graphene sheets via the functional groups in graphene oxide to maximize electronic transport and mechanical reinforcement between sheets and the partial restacking of the sheets to increase the material density to about 1 g cm^‐3. These GDCs exhibit properties 3–6 orders of magnitude higher than previously reported 3D graphene assemblies.     

Effect of superatmospheric oxygen packaging on sensorial quality,spoilage, and Listeria monocytogenes and Aeromonas caviae growth in fresh processed mixed salads

Atmospheres with O2 levels higher than 70 kPa have recently been suggested as an innovation to modified atmosphere packaging (MAP) for fresh processed vegetables to maintain sensory quality and safety. In the present work, mixed vegetable salad collected from a commercial processing plant and stored with the MAP technique was studied. Two gas mixtures were actively generated by using an initial O2 concentration of 95 kPa and combined with two plastic films. The low-barrier film permeability for O2 was 1,629 mlO2/m2 x 24 h x atm with 30 microm of thickness (Hyplast, Hoogstraten, Belgium) and the O2 permeability of the high-barrier film was 2 mlO2/m2 x 24h x atm with 150 microm of thickness (Euralpack, Wommelgen, Belgium) at 23 degrees C. As control, active conventional MAP with application of 3 to 5 kPa of O2 and 6 to 8 kPa of CO2 was used. Packaged salads were stored up to 8 days at 4 degrees C and at temperatures simulating chilled distribution chain conditions. Microbial safety and sensory quality, as well as the survival of inoculated Listeria monocytogenes and Aeromonas caviae, were monitored. The effect of superatmospheric O2 on the growth of aerobic microflora was variable. Under superatmospheric conditions, lactic acid bacteria and members of Enterobacteriaceae were inhibited. Nevertheless, growth of yeast and A. caviae seem to be stimulated by superatmospheric O2, whereas growth of psychrotrophic bacteria and L monocytogenes was not affected. The overall visual appearance (mainly color) of the mixed vegetable salads was better maintained and the shelf life prolonged when packaged under O2 concentrations greater than 50 kPa.     

Evaluation of current operating standards for chlorine dioxide in disinfection of dump tank and flume for fresh tomatoes

Standard postharvest unit operations that rely on copious water contact, such as fruit unloading and washing, approach the criteria for a true critical control point in fresh tomato production. Performance data for approved sanitizers that reflect commercial systems are needed to set standards for audit compliance. This study was conducted to evaluate the efficacy of chlorine dioxide (ClO(2)) for water disinfection as an objective assessment of recent industry-adopted standards for dump tank and flume management in fresh tomato packing operations. On-site assessments were conducted during eight temporally distinct shifts in two Florida packinghouses and one California packinghouse. Microbiological analyses of incoming and washed fruit and dump and flume system water were evaluated. Water temperature, pH, turbidity, conductivity, and oxidation-reduction potential (ORP) were monitored. Reduction in populations of mesophilic and coliform bacteria on fruit was not significant, and populations were significantly higher (P < 0.05) after washing. Escherichia coli was near the limit of detection in dump tanks but consistently below the detection limit in flumes. Turbidity and conductivity increased with loads of incoming tomatoes. Water temperature varied during daily operations, but pH and ORP mostly remained constant. The industry standard positive temperature differential of 5.5°C between water and fruit pulp was not maintained in tanks during the full daily operation. ORP values were significantly higher in the flume than in the dump tank. A positive correlation was found between ORP and temperature, and negative correlations were found between ORP and turbidity, total mesophilic bacteria, and coliforms. This study provides in-plant data indicating that ClO(2) can be an effective sanitizer in flume and spray-wash systems, but current operational limitations restrict its performance in dump tanks. Under current conditions, ClO(2) alone is unlikely to allow the fresh tomato industry to meet its microbiological quality goals under typical commercial conditions.     

上海地区中青年女性文胸号型选择情况调查与分析

通过对444名长期居住（15年以上）在上海地区、学历在高中以上且年龄为25～45岁的女性胸部细部尺寸的测量,按照国际标准文胸号型尺寸计算出该444名女性理论应选择的文胸号型（Theoretical Choice）;并通过问卷调查的方式,获得了该444名女性实际生活中依靠主观感觉所选择的文胸号型（ActualChoice...     

Influence of β-lactoglobulin and β-casein on Listeria innocua inactivation by pulsed light

The effect of β-lactoglobulin and β-casein on the pulsed light (PL) inactivation of Listeria innocua was evaluated. For low protein concentrations (β-lactoglobulin and β-casein up to 10 mg/mL), the lowest fluences applied (0.2 J/cm(2)) induced more than 7 Log reductions in cell counts. However, higher fluences were needed to induce similar reduction in L. innocua counts when this bacterium was suspended in solutions of higher protein concentration. The fluence required to induce similar microbial inactivation was lower in β-casein than in β-lactoglobulin solutions. For all protein solutions, the inactivation curves followed first order kinetics. The specific inactivation rate for L. innocua inactivation in protein solutions depended on the quantity of light transmitted in the range 230-290 nm by protein solutions. This work shows that PL technology could be used for the decontamination of high protein content solutions like whey or even higher protein concentration solutions.     

Keeping quality and safety of minimally fresh processed melon

Fresh-cut Amarillo melon was stored under passive modified atmosphere packaging (MAP) for 14 days at 5 °C. Three commercial films were tested: microperforated polypropylene (MPP), bioriented PP (BPP), and oriented PP (OPP). As a control, a macroperforated PP film was used. The effect of a citric acid dip treatment (0.52 mM) on the quality of the melon pieces packaged in OPP film was also evaluated. A similar final gas composition (4 kPa O2 plus 12–13 kPa CO2) within packages was achieved by using the three tested films. This atmosphere was effective for maintaining sensorial quality and microbial safety and for avoiding weight loss and translucency. When citric acid dip was applied, a reduction of microbial counts, a low discoloration, an increase of lightness, and a general improvement of visual appearance were found. However, after 14 days of storage, neither MAP treatments nor citric acid dip were enough to avoid softening of at least 23%, although the highest value (32%) was found in control pieces. Taking into account safety, quality attributes and consumer acceptance, shelf life of fresh processed melon stored under the studied MAP conditions could be stabilised for 10 days.     

Quality Changes and Shelf-Life Prediction of a Fresh Fruit and Vegetable Purple Smoothie

The sensory, microbial, and bioactive quality changes of untreated (CTRL) and mild heat-treated (HT; 90 °C/45 s) smoothies were studied and modelled throughout storage (5, 15 and 25 °C). The overall acceptability was better preserved in HT samples being highly correlated (hierarchical clustering) with the flavour. The sensory quality data estimated smoothie shelf-life (CTRL/HT) of 18/55 (at 5 °C), 4.5/12 (at 15 °C) and 2.4/5.8 (at 25 °C) days. The yeast and mould growth rate was lower in HT compared to CTRL while a lag phase for mesophiles/psychrophiles was observed in HT-5/15 °C. HT and 5 °C storage stabilised the phenolic content. Ferric reducing antioxidant power reported the best correlation (R ² = 0.94) with the studied bioactive compounds, followed by ABTS (R ² = 0.81) while DPPH was the total antioxidant capacity method with the lowest adjustment (R ² = 0.49). Conclusively, modelling was used to estimate the shelf-life of a smoothie based on quality retention after a short-time, high-temperature heat treatment that better preserved microbial and nutritional quality during storage.