Reduction of Escherichia coli O157:H7 viability on leafy green vegetables by treatment with a bacteriophage mixture and trans-cinnamaldehyde

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major foodborne pathogen responsible for frequent gastroenteritis outbreaks. Phages and essential oils can be used as a natural antimicrobial method to reduce bacterial pathogens from the food supply. The objective of this study was to determine the effect of a bacteriophage cocktail, BEC8, alone and in combination with the essential oil trans-cinnameldehyde (TC) on the viability of a mixture of EHEC O157:H7 strains applied on whole baby romaine lettuce and baby spinach leaves. The EHEC O157:H7 strains used were Nal^R mutants of EK27, ATCC 43895, and 472. Exponentially growing cells from tryptic soy (TS) broth cultures were spot inoculated on leaves and dried. EHEC cells were placed at low, medium, and high inoculum levels (10⁴, 10⁵, and 10⁶ CFU/mL, respectively). Appropriate controls, BEC8 (approx. 10⁶ PFU/leaf), and TC (0.5% v/v) were applied on treated leaves. The leaves were incubated at 4, 8, 23, and 37 °C in Petri dishes with moistened filter papers. EHEC survival was determined using standard plate count on nalidixic acid (50 μg/mL) Sorbitol MacConkey agar. No survivors were detected when both leaves were treated with BEC8 or TC individually at low inoculum levels after 24 h at 23 and 37 °C. When the EHEC inoculum size increased and/or incubation temperature decreased, the efficacy of BEC8 and TC decreased. However, when the two treatments were combined, no survivors were detected after 10 min at all temperatures and inoculum levels on both leafy greens. These results indicated that the BEC8/TC combination was highly effective against EHEC on both leafy greens. This combination could potentially be used as an antimicrobial to inactivate EHEC O157:H7 and reduce their incidence in the food chain.     

Field and numerical analysis of in-situ air sparging: a case study

An in-situ air sparging operation was used to remediate the sandy subsurface soils and shallow groundwater under a drum storage site near Chicago, IL, where either periodic or random spillage of a light non-aqueous phase liquid (LNAPL) occurred between 1980 and 1987. Both field measurements and model simulations using commercially available computer software suggested that microbial degradation was the most significant contributor to the removal of contaminant mass. Toluene, ethylbenzene and total xylenes (TEX), which were of major concern with regards to reaching clean-up criteria at the site, were observed to decline by 88% in concentration. Furthermore, up to 97% of the total mass removed through microbial degradation consisted of TEX. Of the total contaminant spill, up to 23% of initial organic chemical mass was removed through microbial degradation compared to less than 6% by physical stripping. Greater loss to microbial degradation is most likely attributed to the relatively low air injection rate used during the course of the air sparging remediation. Evaluation of air sparging at the site using model simulations supported this analysis by estimating 140 and 620 kg of total contaminant mass being removed through volatilization and biodegradation, respectively. An evaluation of several system design parameters using model simulations suggested that only the type of sparging operation (i.e. pulsed or continuous) was significant in terms of total contaminant removal time, while both the sparging operation and air injection rate were significant in terms of removal of a critical species, total xylenes.     

Factors affecting air sparging remediation systems using field data and numerical simulations

Field data from five air sparging sites were used to assess the effect of several soil, contaminant, and air sparging system factors on the removal time and associated costs required to reach specified clean-up criteria. Numerical simulations were also performed to better assess the field data and to expand the data sets beyond the five field sites. Ten factors were selected and evaluated individually over a range of values based on information from practitioners and the literature. Trends in removal time and removal cost to reach a specified clean-up criterion were analyzed to ascertain the conditions controlling contaminant removal with variations in each factors' value. A linear sensitivity equation was used to quantify system dynamics controlling the observed contaminant removal trends for each factor. Factors found most critical across all field sites in terms of removal time and/or cost were contaminant type, sparge pulsing schedule, number of wells, maximum biodecay rate, total soil porosity, and aquifer organic carbon content. Factors showing moderate to low effect included the depth of the sparge point below the water table, air injection rate/pressure, horizontal air conductivity, and anisotropy ratio. At each field site, subsurface coverage of sparged air, sparged air residence time, contaminant equilibrium in the system, contaminant phase distribution, oxygen availability to microbes, and contaminant volatility seem to control the system responses and were affected by one or more of the 10 factors evaluated.     

RBFNN versus FFNN for daily river flow forecasting at Johor River,Malaysia

Streamflow forecasting can have a significant economic impact, as this can help in water resources management and in providing protection from water scarcities and possible flood damage. Artificial neural network (ANN) had been successfully used as a tool to model various nonlinear relations, and the method is appropriate for modeling the complex nature of hydrological systems. They are relatively fast and flexible and are able to extract the relation between the inputs and outputs of a process without knowledge of the underlying physics. In this study, two types of ANN, namely feed-forward back-propagation neural network (FFNN) and radial basis function neural network (RBFNN), have been examined. Those models were developed for daily streamflow forecasting at Johor River, Malaysia, for the period (1999–2008). Comprehensive comparison analyses were carried out to evaluate the performance of the proposed static neural networks. The results demonstrate that RBFNN model is superior to the FFNN forecasting model, and RBFNN can be successfully applied and provides high accuracy and reliability for daily streamflow forecasting.     

Performance evaluation of silty sand reinforced with fibres

Triaxial compression tests were conducted to evaluate the response of randomly distributed fibre on the strength of reinforced silty sand. In this study, oil palm empty fruit bunch (OPEFB) fibre was mixed with silty sand soil to investigate the increase of shear strength during triaxial compression. The specimens were tested under drained and undrained conditions with 0.25% and 0.5% content of OPEFB fibres of different lengths (i.e. 15 mm, 30 mm and 45 mm). In addition, OPEFB fibres coated with acrylic butadiene styrene thermoplastic were tested to determine the effect of coating on reinforcement. Inclusion of randomly distributed discrete fibres significantly improved the shear strength of silty sand. Coated OPEFB fibres increased the shear strength of silty sand much more compared to uncoated fibres. Coating fibres increases interface friction between fibre and soil particles by increasing the surface area. Reinforced silty sand containing 0.5% coated fibres of 30 mm length exhibited approximately 25% increase in friction angle and 35% in cohesion under undrained loading conditions compared to those of unreinforced silty sand. The results indicate that the shear strength parameters of the soil-fibre mixture (i.e. Φ′ and c′) can be improved significantly.     

The use of pretreated palm oil mill effluent for acetone–butanol–ethanol fermentation by Clostridium saccharoperbutylacetonicum N1-4

Palm oil mill effluent (POME) was used as an acetone–butanol–ethanol (ABE) fermentation medium using Clostridium saccharoperbutylacetonicum N1-4. Various pretreatment methods were applied on POME to increase the amount of fermentable sugars leading to enhanced ABE production. Sulfuric acid-treated POME (SA-POME) method was found to give the highest yield of total reducing sugars (glucose, cellobiose, xylose, and arabinose) as compared to other pretreatment methods. An increment in the concentration of H₂SO₄ from 1 to 2% resulted in the enhanced release of reducing sugars (18.3, 26.3?g/L, respectively). However, the treatment of POME with 3% H₂SO₄, decreased the reducing sugars to 21.6?g/L and consequently, the total ABE production was also reduced. The highest yield of ABE was observed from a culture grown with POME treated by 1% H₂SO₄. The total ABE production from 1, 2, and 3% SA-POME was obtained as 2.2, 0.45, and 0.41?g/L, respectively. Although, enzymatically treated POME (EH-POME) could produce 4.42?g/L glucose, sulfuric acid treatment (1%) was able to liberate only 1.76?g/L glucose, ABE production was higher when 1% SA-POME was used. Low yield of ABE from enzymatically treated POME can be attributed to the production of some inhibitors during hydrolysis of POME. When EH-POME was treated with XAD-4 resin to nullify the inhibitors, the production of ABE was increased to 4.29?g/L, and ABE yield was also increased to 0.29?g/g. In conclusion, enzymatic hydeolysis of POME followed by elution to XAD-4 column can be proposed as the best pretreatment method for highest productivity of ABE. It was found that addition of P2 medium to the POME hydrolysates was able to improve the production of butanol except in raw POME and sulfuric acid hydrolysates.     

Optimisation of gelatine extraction from hoki (Macruronus novaezelandiae) skins and measurement of gel strength and SDS–PAGE

The extraction of hoki (Macruronus novaezelandiae) gelatine was optimised using Response Surface Methodology (RSM) and gel strength and SDS–PAGE were evaluated. The optimum conditions for extraction were 0.75 M NaCl for 9 min of pre-treatment time and hot water extraction at 49.3 °C for 60 min. Results showed that the predicted yield by RSM (17.4%) closely matched the experimental yield of 17.6%. SDS–PAGE showed that hoki gelatine contained higher molecular weight subunits (∼191 kDa) but lower gel strength (197 ± 5 g) than those from porcine (307 ± 8.4 g) or bovine (273 ± 16.1 g) gelatine determined at 7 °C. However, hoki gelatine gel strength was significantly higher than those from other cold-water fish species reported in literature, which could account for the slight differences in methodologies reported.     

Education in sustainable production in US universities

The evolution and current status of sustainable production education (SPE) in the United States is reviewed, both as a discrete entity and as an intersection of multiple disciplines. This paper (a) examines the current array of compatible and conflicting theories that guide the alternative approaches to SPE, (b) reviews the wide array of applications to which such theories and associated methodologies have been applied, and (c) presents a case study of the emerging interdisciplinary approach to SPE at Purdue University in West Lafayette, Indiana, USA, and its network of national and international collaborators. North Atlantic Treaty Organization (NATO) Committee on the Challenges to Modern Society (CCMS). Pilot study on clean products and processes Annual meeting, May 2–6, 2004, Budapest, Hungary

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