Uncertainty in particle number modal analysis during transient operation of compressed natural gas, diesel, and trap-equipped diesel transit buses

The relationships between transient vehicle operation and ultrafine particle emissions are not well-known, especially for low-emission alternative bus technologies such as compressed natural gas (CNG) and diesel buses equipped with particulate filters/traps (TRAP). In this study, real-time particle number concentrations measured on a nominal 5 s average basis using an electrical low pressure impactor (ELPI) for these two bus technologies are compared to that of a baseline catalyst-equipped diesel bus operated on ultralow sulfur fuel (BASE) using dynamometer testing. Particle emissions were consistently 2 orders of magnitude lower for the CNG and TRAP compared to BASE on all driving cycles. Time-resolved total particle numbers were examined in terms of sampling factors identified as affecting the ability of ELPI to quantify the particulate matter number emissions for low-emitting vehicles such as CNG and TRAP as a function of vehicle driving mode. Key factors were instrument sensitivity and dilution ratio, alignment of particle and vehicle operating data, sampling train background particles, and cycle-to-cycle variability due to vehicle, engine, after-treatment, or driver behavior. In-cycle variability on the central business district (CBD) cycle was highest for the TRAP configuration, but this could not be attributed to the ELPI sensitivity issues observed for TRAP-IDLE measurements. Elevated TRAP emissions coincided with low exhaust temperature, suggesting on-road real-world particulate filter performance can be evaluated by monitoring exhaust temperature. Nonunique particle emission maps indicate that measures other than vehicle speed and acceleration are necessary to model disaggregated real-time particle emissions. Further testing on a wide variety of test cycles is needed to evaluate the relative importance of the time history of vehicle operation and the hysteresis of the sampling train/dilution tunnel on ultrafine particle emissions. Future studies should monitor particle emissions with high-resolution real-time instruments and account for the operating regime of the vehicle using time-series analysis to develop predictive number emissions models.     

Serological characterization and prevalence of spvR genes in Salmonella isolated from foods involved in outbreaks in Brazil

Salmonella strains (n = 75) isolated from foods involved in foodborne outbreaks occurred in Rio Grande do Sul State, Brazil, during 1999 and 2000 were studied. Strains were serotyped and submitted to PCR analysis to verify the prevalence of Salmonella plasmid virulence (spvR) regulatory gene. Among the 75 isolates, 73 (97%) were classified as Salmonella enterica serovar Enteritidis. All of the Salmonella strains isolated in 1999 were classified as serotype Enteritidis, whereas in 2000 two isolates were serotyped as Salmonella Derby and Salmonella Typhimurium. Regarding the prevalence of spvR gene, 62 strains (82.7%) were PCR positive, and a positive correlation (P < 0.05) between the strains of Salmonella Enteritidis and the presence of spvR gene was demonstrated, which suggests that this gene is a characteristic of the Salmonella Enteritidis analyzed.     

A comparison of halothane homozygous negative and positive pietrain sire lines in relation to carcass and meat quality, and welfare traits

Barrows (n=164) and gilts (n=249) from crosses of a Pietrain homozygous halothane recessive (Pi nn) and two Pietrain homozygous dominant (Pi NN-a and Pi NN-b) sire lines with Landrace×Large White NN sows, were used to study the effect of terminal sire and pre-slaughter treatment on meat quality and animal welfare. The pigs from each of the two farms where they were finished were delivered to the abattoir in two batches differing in the pre-slaughter conditions. A total of 90 pigs (54 NN and 36 Nn) were assigned to a long pre-slaughter treatment (6 h transport and 14.5 h lairage) and 89 (57 NN and 33 Nn) to a short pre-slaughter treatment (4.5 h transport and 2.5 h lairage) in Farm 1, and 118 (65 NN and 53 Nn) to the long (7 h transport and 14 h lairage) and 114 (66 NN and 48 Nn) to the short pre-slaughter treatment (1.5 h transport and 2 h lairage) in Farm 2. In Farm 1, heart rate of 3 NN and 3 Nn gilts was recorded throughout loading and transport and blood samples from 5 NN and 5 Nn were collected before loading and after transport to measure cortisol, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH). Carcasses were classified and commercial cutting was carried out. At 24 h, meat quality was assessed on the Longissimus thoracis muscle by measuring electrical conductivity (PQM), colour (Minolta CR 200 and Japanese scale), pHu and drip losses. Halothane carriers showed a higher mean heart rate and higher increase in CPK levels (P<0.05) after transport in the short pre-slaughter treatment than halothane free pigs. No effect was observed in cortisol or LDH values. Pi NN-a sired pigs had a higher live and carcass weight (P<0.001) and loin depth (P<0.05), but lower killing out percentage (P<0.01) and leg yield (P<0.01) compared with the progeny of the other two terminal sires. Gilts were leaner (P<0.001), had a higher killing out percentage (P<0.001) and higher yields of primal cuts (P<0.001) compared with barrows. Pi nn sired pigs had poorer meat quality (higher PQM values in both farms, P<0.01) than Pi NN-a sired pigs. Long pre-slaughter treatment resulted in darker meat (P<0.01) in both farms and in higher pHu (P<0.001) in Farm 1 than short pre-slaughter treatment. Conversely, pigs subjected to the short pre-slaughter treatment showed higher PQM values (P<0.01) in Farm 1 and higher PSE percentage (P<0.05) in both farms compared to the ones subjected to the long pre-slaughter treatment. These results suggest that Pietrain halothane free sire lines could produce similar results on carcass quality to halothane carriers, without compromising meat quality and welfare.     

Evaluation of commercial red fruit juice concentrates as ingredients for antioxidant functional juices

Phenolic profiles of nine red fruit commercial juice concentrates were characterised by means of high -performance liquid chromatography–diode array detection–mass spectrometry–mass spectrometry. Flavonoids such as anthocyanins, flavonols, hydroxycinnamic acid derivatives, stilbenoids, flavan 3-ols, ellagic acid derivatives, and other phenolic acids, were both identified and quantified in chokeberry, elderberry, blackcurrant and redcurrant, strawberry, red grape, cherry, plum, and raspberry commercial juice concentrates. Once the characterisation was carried out, the antioxidant capacity of each concentrate was assessed in vitro by means of two different methods: the 2,2-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (Trolox equivalent antioxidant capacity) method and the 2,2-diphenyl-1-picrylhydrazyl radical method. Elderberry, chokeberry and blackcurrant concentrates were the richest in total phenolics and they had the strongest antioxidant capacity; therefore, these three juices may have huge interest as ingredients in the design of functional juices.     

Influence of fermentation oxygen partial pressure on semicontinuous acetification for wine vinegar production

This paper describes semicontinuous acetic acid fermentations for wine vinegar production carried out with different aerating gas compositions ranging from 21% (air) to 63% oxygen content and using low aeration (3.7 h^–1, vvm), in order to study the influence of the oxygen partial pressure on the aerating gas supplied to the reactor in this industrial biotransformation process. The acetification process was conducted in 6- to 100-l reactors. The overall acetic acid productivity increased from 0.72 g l^–1 h^–1 with air to 1.35 g l^–1 h^–1 when oxygen-rich (36%) air was used. The same behaviour was observed for the maximum acetification rate, and therefore the total process time was reduced in proportion to the increase in productivity, from 65 h using air to 35 h using an aerating gas mixture containing 36% oxygen. The yield of the process was high, 96–99%; the final concentration of acetic acid reached was 116–118 g l^–1; and the substrate yield coefficient based on ethanol metabolised was higher using oxygen-rich air than with air. It was not feasible to carry out semicontinuous acetification cycles with an oxygen content higher than 40%, and when the oxygen content was 63%, the process stopped during the first cycle with very little acetic acid production. Moreover, an inverse relationship between the acetic acid formation rate profile in the course of the acetification process and the amount of dissolved acetaldehyde in the fermentation broth formed by the acetic bacteria was observed.     

Effect of vacuum and modified atmosphere packaging on the quality of pork loin

The effect of packaging in protective atmospheres on the process of lipid oxidation, colour and water retention capacity of pork loin chops during refrigerated storage was investigated. The use of modified atmospheres with a high oxygen concentration (70%) acted as a pro-oxidation factor both for fatty acids and for cholesterol (an increase of 86.4% on the initial COPS content). No significant advantages were found in the use of these atmospheres concerning the colour of the meat. Vacuum packaging was seen to be an interesting alternative in the packaging of pork, due to the fact that it increases oxidative stability, which brings about greater colour stability and therefore increases the shelf life. The only disadvantage of this type of packaging is that it increases initial weight loss (5.1% on day 2 of storage).     

Influence of different aging systems and oak woods on aged wine color and anthocyanin composition

The evolution of a red wine, Cigales appellation in origin, was studied during its storage in three different aging systems (barrels, chips, and staves) made of different kinds of oak wood (American, French, and Hungarian). The results obtained were analyzed in order to determine the content of anthocyanins in wine according to the aging system used. The studied variables were monoglucosides of delphidin, cyanindin, peonidin, petunidin and malvidin (as acetic and p-coumaric esters), as well as vitisin A, malvidin-3-O-caffeylglucoside, and color variables. The relationship between the anthocyanins and color variables stressed the importance of these compounds during the formation of pigments characteristic of aged wine, and highlighted how they are affected by the aging system chosen.Analysis of the results allowed us to define the evolution of the wine accordingly to the aging system and the botanical species of wood used. Wine treated with chips evolved more quickly than wines treated with the other two systems, because there was a higher loss of anthocyanins and an increase in brownish tonalities. On the other hand, wine treated with Hungarian oak wood suffered a slightly higher loss of anthocyanins than those aged with French and American oak wood.     

Volatile compounds on the surface and within Iberian dry-cured loin

The profile of volatile compounds from external and internal areas of Iberian dry-cured loin was studied by headspace solid-phase microextraction. Higher levels of 16 volatile compounds (hexane, decane, 3-methylbutanal, several sulphur compounds and some aromatic hydrocarbons) were detected in the outer part of the loins. These differences could be owing to several factors, such as greater exposure to oxygen and dehydration conditions in the surface of the product, which favour oxidation reactions and Strecker degradation of amino acids. Moreover, the addition of spices on the surface and the proximity of a mould layer growing on the surface of the product could also contribute to the higher levels of these compounds on the external layer. However, other sulphur compounds coming from spices showed similar levels on the surface and within the loins. This different behaviour could be a consequence of different diffusion rates depending on the features of the compound and the matrix.     

Effect of slurry ice on chemical changes related to quality loss during European Hake (Merluccius merluccius) chilled storage

Slurry ice is a biphasic system consisting of small spherical ice crystals surrounded by seawater at subzero temperature. Its employment was evaluated in the present work as a new chilled storage method for whole European Hake (Merluccius merluccius) and compared to traditional flake icing. Different chemical analyses (nucleotide degradation, formaldehyde formation, lipid hydrolysis and oxidation, interaction compound formation, and electrophoretic protein profiles) related to quality changes were analysed and compared to sensory evaluation. An inhibitory effect on quality loss mechanisms was observed for the slurry ice treatment, according to nucleotide degradation (K value), free formaldehyde content, browning development, and sarcoplasmic protein profiles. No differences in lipid hydrolysis and oxidation could be distinguished by a comparison between both icing conditions. The sensory analysis showed a higher shelf-life time for slurry icing than flake icing (12 days and 5 days, respectively). Results confirm the practical advantages of using slurry ice as a chilled storage method.     

Production of fermentable media from vine‐trimming wastes and bioconversion into lactic acid by Lactobacillus pentosus

Trimmings of vineshoots, an agricultural waste with little use, were hydrolysed with dilute sulphuric acid (1–5%) in order to obtain sugar solutions suitable as fermentation media. The operational conditions for hydrolysis were selected on the basis of both the generation of hemicellulosic sugars (mainly xylose) and glucose and the concentrations of reaction byproducts affecting fermentation (furfural, hydroxymethylfurfural and acetic acid). Hemicellulosic hydrolysates were supplemented with nutrients and fermented with Lactobacillus pentosus, without any previous detoxification stage, to produce lactic acid. Under the best operational conditions assayed (3% H₂SO₄ and 15 min), 21.8 g lactic acid l^?1 was produced (Q_P = 0.844 g l^?1 h^?1, Y_P/S = 0.77 g g^?1), which represents a theoretical yield of 99.6%. Acetic acid was the primary byproduct formed from xylose, at about 25% of the lactic acid level. Copyright © 2004 Society of Chemical Industry