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The present study evaluated the effects of pressure, depressurization rate, and ratio of inoculum mass to CO2 mass in the inactivation of Staphylococcus aureus, as well as the determination of D-va...

Construction systems based on cross-laminated timber (CLT) have versatility in material development and are an interesting alternative for construction. This study evaluated the structural performance of cross-laminated timber-bamboo produced from wood (Pinus spp.) and bamboo (Dendrocalamus giganteus). Panels were produced by strips (wood and bamboo) assorted, under non-destructive structural grading, to support a better panel configuration. Small-length pine pieces were also included in the study, considering their low added-value and underutilization in sawmills from Telêmaco Borba, Brazil. Gluing tests of small specimens were performed to evaluate the bonding quality of three adhesives: melamine-urea-formaldehyde (MUF), isocyanate polymeric emulsion (IPE), and castor oil-based resin (COR). Shear stress strength parallel to grain between bamboo and wood showed the best performance for MUF resin. After preliminary gluing testing, eight cross-laminated panels were produced with MUF adhesive in a three-layered configuration, with transversal orientation: two external bamboo layers and a central layer of pine wood. Stiffness and rupture strength values were above those specified by the ANSI/APA PGR 320 (2012) standard. Elasticity and rupture moduli were 13,310 MPa and 65 MPa, respectively, showing good potential of this composite for structural uses.

This study evaluated the incidence and identify the Listeria monocytogenes potential contamination in a poultry slaughter plant and assessed the effectiveness of the sanitation process used by the company. A total of 920 breast and 774 thigh samples were analyzed, and L. monocytogenes was found in 8.64 and 44.19% of the samples, respectively. The thigh samples presented more contamination than the breast, throughout the study. The third work shift showed the highest thigh contamination (51%). The contamination percentage was lowest in summer and greater in winter. L. monocytogenes contamination in whole carcasses was absent in samples collected before the chilling process, while 5% of the samples were contaminated after this process. After the automated cutting process, the L. monocytogenes contamination percentage increased linearly, reaching 25 and 70% after 5 h for breast and thighs, respectively. The percentage of contamination on the equipment and utensils used on thigh samples was high during the processing (86.67%) and after the cleaning operation (66.87%). After pre-operational sanitation of equipment and utensils a lower incidence of L. monocytogenes in the production line was observed.

The aim of the present study was to investigate adhesion and biofilm formation on boning knife (new and used; handle – polyethylene and blade – stainless steel) surfaces to evaluate the efficiency of different concentrations of biguanide, peracetic acid and hot water (82.2 °C) in the removal of attached Escherichia coli cells on these surfaces. The bacteria presented an ability of biofilm formation in vitro , being weakly and moderately adherent after 6 h and 24 h respectively. Results showed that the bacterial adhesion increased with the time in both surfaces evaluated (handle and blade). Biofilm formation (1 × 10 3 CFU/cm 2 ) occurred after 6 h of contact time on the handles (new and used surfaces) and blades (new surface). A lower concentration (0.2%) of peracetic acid was efficient in removing adhered cells for 6 h on new and used surfaces. Hot water, typically used in industries, also proved to be efficient in most of the contact times evaluated. It was possible to observe that surface roughness increased with the bacterial adhesion. In this way, hot water with peracetic acid seems to be a promising treatment for the removal of E. coli from boning knives.

Wood is a natural material with great variability in its mechanical properties. This study analyzed the effectiveness of the impulse excitation technique (IET) to characterize the stiffness of 10-year-old Eucalyptus grandis wood at three different heights of 3 m, 6 m, and 9 m from the bottom (height A, B, and C, respectively). A nondestructive testing method—excitation impulse, using Sonelastic® PC-based technology—and a destructive static bending test were used. The mean value for the modulus of elasticity (MOE) in bending was 16.4 GPa and in IET the value was 16.6 GPa. The average values for MOE in static bending were 14.8 GPa at height A, 17.9 GPa at height B, and 17.0 GPa at height C, demonstrating that the greater the height in the trunk of the tree the greater its modulus of elasticity. The correlation equation between static MOE and dynamic MOE was MOESTAT = 0.743.MOEDYN + 4.0983, with the coefficient of determination of R² = 0.85.

This research aimed to produce and determine physical and mechanical properties of three-layered particleboard produced with Pinussp. wood particlesand three different times of press, i.e., 3, 5 and 7 minutes. Recommendations of the Brazilian standard ABNT NBR 14810 [1] were adopted to fundament physical and mechanical tests. The properties evaluated were the modulus of rupture (MOR) and modulus of elasticity (MOE) in static bending; internal bond; thickness swelling; water absorption; moisture content and apparent density.The mean values showed, for the physical properties, that all the panels manufactured achievedthe requirements of theBrazilian standard, and for mechanical properties, only the panelsmanufacturedwith 7minutesofpressing timemet therequirements. From the Tukey test results, timesof the pressingcycleinfluencedsignificantlyin allinvestigatedphysical and mechanicalproperties, showed better results the panels madewithseven minutesof the pressingcycle, implyingthat the time ofseven minutesof the pressingcycle is thebest among theinvestigatedperiodsin the manufactureofparticleboard.

This research aimed to evaluate the influence of storage time (0, 96 hours) ofPinus elliottiipieces and the tests to obtaining modulus of elasticity (static bending and transversal vibration) in glued laminated timber beams, produced with resorcinol based adhesive and 0.8 MPa compaction pressure. After pieces were properly prepared, part of them was used in immediate three manufacturing glulam beams, tested after adhesive cure, and part stored for 96 hours under a roof with a temperature of 25°C and relative humidity of 60% for subsequent manufacturing and testing three other glulam beams. Results of analysis of variance (ANOVA) revealed that the storage period was significant influence in modulus of elasticity obtained in static bending test (8% reduction from 0 to 96 hours). This not occurred with modulus of elasticity obtained by transversal vibration test (no significant influence). ANOVA results showed equivalence of means in both test procedures.

The focus of this research was to study the utilization of residues from bamboo (Dendrocalamus giganteus) lamination in the manufacturing of panels for structural purposes. Bamboo particleboards were produced under three conditions: pure boards, reinforced with bamboo laminas, and with treated particles. Castor oil-based polyurethane was the resin binder, in view of using lower toxicity materials. The mechanical tests were performed according to Brazilian Standard (NBR) 14810-3 (2006) and European Standard (EN) 310 (2000). The results were superior to those recommended by these and other standards for internal adhesion resistance, modulus of rupture, and elasticity in static bending, as well as to the results of other studies. Starch treatment was an unnecessary stage. According to the conditions of this process, the studied panels showed a good potential for construction use. Moreover, the bamboo particleboards are an economically viable, environmentally friendly, and sustainable alternative for the use of waste generated during the processing of Dendrocalamus giganteus bamboo species, allied with castor oil-based polyurethane resin. The reinforced particleboard and its production process are being licensed as an Innovation Patent in Brazil, (BR 1020130133919-1-2013).

The objective of this study was to investigate Listeria monocytogenes adhesion in new and used polyethylene cutting board surfaces and evaluate its removal using different sanitizers (peracetic acid, chlorhexidine, sodium hypochlorite and organic acids). Results showed that the number of adhered cells increased with time on both surfaces evaluated. Statistically significant differences (p < 0.05) between new and used polyethylene surfaces were observed on the adhesion of microorganism. Treatments with the peracetic acid and sodium hypochlorite sanitizers were very effective to inactivate attached L. monocytogenes on the polyethylene cutting board, avoiding the possible formation of biofilms at all contact times studied. Other sanitizers did not succeed in inhibiting completely the pathogen in the maximum concentration (2.0 %) after 24 h of bacterial growth for both surfaces (chlorohexidine), 3 h of bacterial growth on new and 6 h on used surfaces (organic acid). The results indicate that peracetic acid and a sodium hypochlorite treatment present a better method to remove microbial contamination on the surfaces of cutting boards.

The aim of this research was to produce three-layer Medium Density Particleboard (MDP), with the addition of impregnated paper, in the inner layer, in proportions of 1; 5 and 20%. In this study, MDP was composed with particles of small size in outer layers, and larger particles in internal layer. After panel manufacturing, physical and mechanical tests based on Brazilian Code ABNT NBR 14.810 were carried out to determine moisture content; density; thickness swelling; water absorption; modulus of rupture (MOR) and modulus of elasticity (MOE) in static bending and internal adhesion. Test results were compared to commercial panels, produced with 100% Eucalyptus, considering the requirements specified by Brazilian Code. Properties presented values close to normative specifications, indicating positively the possibility of production of MDP using addition of waste paper impregnated.

The objective of this article was to study the influence of the Pinus taeda wood moisture content to the production of EGP (Edge Glued Panel) in the bonding stage, using PVA adhesive. It was analyzed the joint resistances through shear-stress tests and rupture in the bondline. The wood moisture classes adopted to the panels were: “A” ( [8%, 9%[ ), “B” ( [9%, 10%[ ), “C” ( [10%, 11%[ ), “D” ( [11%, 12%[ ) e “E” ( [12%, 13%[ ). After the panel production, it was sawn the specimens for the resistance shear in the bondline tests by traction. The tests results show that it was statistically significant differences to the values of rupture tensions between A class and B, C, D and E classes. The wood medium rupture presented a tendency to reduce with the moisture increase, and the total rupture in the bondline presented a small tendency of a less number of occurrences with the rupture tension increases.

Considering the microbial safety of consumption of raw foods (Asian food), this study aimed to explore the inactivation S. aureus in raw salmon by supercritical CO2 treatment (SC-CO2). For this purpose, experimental design methodology was employed as a tool to evaluate the effects of pressure (120-220 bar), the depressurization rate (10 to 100 bar.min–1) and the salmon:CO2 mass relation (1:0.2 to 1:1.0). It was observed that the pressure and the depressurization rate was statistically significant, i.e. the higher the system pressure and depressurization rate, the greater the microbial inactivation. The salmon: CO2 mass relation did not influence the S. aureus inactivation in raw salmon. There was a total reduction in S. aureus with 225 bar, a depressurizing rate of 100 bar.min–1, a salmon: CO2 mass relation of 1:0.6, for 2 hours at 33 °C.

The economic exploitation of rubber tree (Hevea brasiliensis) usage is primarily directed toward latex extraction. After the productive life of the rubber tree forest, the managed area is harvested for planting reformulation. The harvested wood is most often used for energy generation purposes. The aim of this work was to study the feasibility of using rubberwood waste and castor oil-based polyurethane resin in the production of particleboards. Homogeneous and heterogeneous panels were made with nominal dimensions of 500 x 500 mm and thicknesses of 10 mm using particles from GT1 and RRIM600 clones of the rubber tree and 12% castor oil-based polyurethane adhesive. The panels were pressed at 140 °C for 12 min with 40 kgf/cm2 specific pressure. Density, moisture content, thickness swelling, water absorption for 2 and 24 h, static bending, and internal bonding determinations were performed according to the Brazilian Standard (NBR) 14810-3 (2006) for the physical-mechanical panel characterization. The results show that using Hevea brasiliensis in particleboard production is viable. However, multilayer boards exhibited better results.

This study aimed to produce and determine physical and mechanical properties of three layers particleboards produced with Eucalyptus sp. particles, in outer layers, and Eucalyptus urograndis e Eucalyptus saligna bark, in internal layer. Recommendations of the Brazilian Code ABNT NBR 14810-3:2006 were adopted to fundament physical and mechanical tests. Properties considered were modulus of rupture (MOR) and modulus of elasticity (MOE) in static bending; internal adhesion; thickness swelling; water absorption; moisture content and density of the panels. Four different panel compositions were studied, with 5, 10, 15 and 20% of bark (related to particle mass) the internal layer. Results were compared with the requirements of: Brazilian Code ABNT NBR 14810-2; European Code EN 312 and related literature. The produced panels were adequate to all the values stipulated the cited codes and also superior to similar studies found in the literature, for all compositions of bark in internal layer, except for the moisture content test, in which only the composition of 5 % hull met the normative specifications.