Ciutats

[p.4] "La culpa de tot és dels grans"[p.8] Què van fer les sargantanes i els dragons?[p.13] Desenvolupament urbà sostenible[p.21] Una dura lliçó per ser apresa[p.32] La ciutat com a aventura iniciàtica[p.37] Una competició per la sostenibilitat?[p.44] Entrevista a Salvador RuedaPeer Reviewe

Quantitative risk assessment of human salmonellosis and listeriosis related to the consumption of raw milk in Italy.

Two quantitative risk assessment (RA) models were developed to describe the risk of salmonellosis and listeriosis linked to consumption of raw milk sold in vending machines in Italy. Exposure assessment considered the official microbiological records monitoring raw milk samples from vending machines performed by the regional veterinary authorities from 2008 to 2011, microbial growth during storage, destruction experiments, consumption frequency of raw milk, serving size, and consumption preference. Two separate RA models were developed: one for the consumption of boiled milk and the other for the consumption of raw milk. The RA models predicted no human listeriosis cases per year either in the best or worst storage conditions and with or without boiling raw milk, whereas the annual estimated cases of salmonellosis depend on the dose-response relationships used in the model, the milk storage conditions, and consumer behavior in relation to boiling raw milk or not. For example, the estimated salmonellosis cases ranged from no expected cases, assuming that the entire population boiled milk before consumption, to a maximum of 980,128 cases, assuming that the entire population drank raw milk without boiling, in the worst milk storage conditions, and with the lowest dose-response model. The findings of this study clearly show how consumer behavior could affect the probability and number of salmonellosis cases and in general, the risk of illness. Hence, the proposed RA models emphasize yet again that boiling milk before drinking is a simple yet effective tool to protect consumers against the risk of illness inherent in the consumption of raw milk. The models may also offer risk managers a useful tool to identify or implement appropriate measures to control the risk of acquiring foodborne pathogens. Quantification of the risks associated with raw milk consumption is necessary from a public health perspective

Four-Year Monitoring of Foodborne Pathogens in Raw Milk Sold by Vending Machines in Italy

Prevalence data were collected from official microbiological records monitoring four selected foodborne pathogens (Salmonella spp., Listeria monocytogenes, Escherichia coli O157:H7 and Campylobacter jejuni) in raw milk sold by self-service vending machines in seven Italian Regions (n. 60907 samples from 1239 vending machines) during the years 2008 to 2011. Data of samples analyzed both by culture-based and real-time PCR methods were collected in one Region. A total of 100 raw milk consumers in four regions were interviewed while purchasing raw milk from vending machines. One hundred and seventy eight samples out of 60907 were positive for one of the four foodborne pathogens investigated; overall, 18 samples were positive for Salmonella spp., 83 for L. monocytogenes, 24 for E. coli O157:H7 and 53 for C. jejuni in the seven Regions investigated. There were no significant differences in prevalence among Regions, but a significant increase in C. jejuni prevalence was observed over the years. A comparison of the two different analysis methods showed that real-time PCR is from 2.71 to 9.40 times more sensitive than culture-based method. Data on consumer habits showed that some behaviors may enhance the risk of infection due to raw milk consumption: 37% of consumers do not boil milk before consumption, 93% never use an insulated bag to transport raw milk home, and raw milk is consumed by children under five years of age. The study emphasizes that end-product controls alone are not sufficient to guarantee an adequate level of consumer protection. The beta distribution of positive samples in this study and the data on raw milk consumer habits are useful and appropriate for the development of a National Quantitative Risk Assessment of Salmonella spp., L. monocytogenes, E. coli O157 and C. jejuni related to raw milk consumption

Distribution of Transferable Antibiotic Resistance Genes in Laboratory-Reared Edible Mealworms (Tenebrio molitor L.)

In the present study, the distribution of antibiotic resistance genes in laboratory-reared fresh mealworm larvae (Tenebrio molitor L.), their feeding substrates (carrots and wheatmeal), and frass was assessed. Microbial counts on selective media added with antibiotics highlighted the presence of lactic acid bacteria resistant to ampicillin and vancomycin and, more specifically, enterococci resistant to the latter antibiotic. Moreover, staphylococci resistant to gentamicin, erythromycin, tetracycline, and vancomycin were detected. Enterobacteriaceae resistant to ampicillin and gentamicin were also found, together with Pseudomonadaceae resistant to gentamicin. Some of the genes coding for resistance to macrolide-lincosamide-streptogramin B (MLSB) [erm(A), erm(C)], vancomycin [vanA, vanB], tetracycline [tet(O)], and β-lactams [mecA and blaZ] were absent in all of the samples. For the feeding substrates, organic wheatmeal was positive for tet(S) and tet(K), whereas no AR genes were detected in organic carrots. The genes tet(M), tet(K), and tet(S) were detected in both mealworms and frass, whereas gene aac-aph, coding for resistance to amynoglicosides was exclusively detected in frass. No residues for any of the 64 antibiotics belonging to 10 different drug classes were found in either the organic wheatmeal or carrots. Based on the overall results, the contribution of feed to the occurrence of antibiotic resistance (AR) genes and/or antibiotic-resistant microorganisms in mealworm larvae was hypothesized together with vertical transmission via insect egg smearing

Hydrogenation of Allyl Alcohols Catalyzed by Aqueous Palladium and Platinum Nanoparticles.

Hydrogenations of allyl alcohols in aqueous media, at room temperature and pressure, were performed in presence of Pd or Pt lignin nanoparticles as catalysts to obtain saturated alcohols

The Role of Nanoparticle Catalysis in the Nylon Production

Renewal in the world production of plastics with growing amounts of building blocks from biomass is a pressing demand among society. Adipic acid is one of the monomers of nylon 6,6, and, traditionally, is obtained from fossil sources, but it is possible to reduce the muconic acids, deriving it from biomass, to obtain adipic acid. However, these catalyzed reactions use commonly hazardous conditions or reagents; in this study, a pathway to obtain a bio-adipic acid, following the Green Chemistry, is reported. Metal nanoparticles (M NPs; M = Pd, Pt, Ru, Rh) were synthesized in water at 80 °C using sodium lignosulphonate as a reducing and stabilizing agent. They were characterized by TEM and XRD techniques: Pd NPs were larger (21 nm) and spherical in shape; Pt NPs were irregular; Ru and Rh NPs were smallest (1.9 and 5.3 nm, respectively). M NPs were tested as catalyst in the hydrogenation reactions of dicarboxylic acids (fumaric, malonic, trans,trans- and cis,cis-muconic acids) in water at room pressure and temperature. The NPs transformed selectively fumaric and malonic acids to succinic acid, although with different yields. Ru and Pt NPs were moderately active while with Pd NPs, 80% of succinic acid was obtained and with Rh NPs, 100% was observed. Carrying out the hydrogenations on muconic acids at pH 5, the formation of adipic acid was observed with all NPs but selectivities in the presence of Ru, Pt and Pd NPs were not excellent. The selectivity with Rh NPs was remarkable (86% from cis,cis- and about 100% from trans,trans-muconic acid) considering the mild conditions; furthermore, it is attractive that the adipic acid was obtained also from the cis,cis isomer which can be produced from biomass

ChemInform Abstract: Hydrogenation of Allyl Alcohols Catalyzed by Aqueous Palladium and Platinum Nanoparticles.

Hydrogenations of allyl alcohols in aqueous media, at room temperature and pressure, were performed in presence of Pd or Pt lignin nanoparticles as catalysts to obtain saturated alcohols

The Role of Nanoparticle Catalysis in the Nylon Production

Renewal in the world production of plastics with growing amounts of building blocks from biomass is a pressing demand among society. Adipic acid is one of the monomers of nylon 6,6, and, traditionally, is obtained from fossil sources, but it is possible to reduce the muconic acids, deriving it from biomass, to obtain adipic acid. However, these catalyzed reactions use commonly hazardous conditions or reagents; in this study, a pathway to obtain a bio-adipic acid, following the Green Chemistry, is reported. Metal nanoparticles (M NPs; M = Pd, Pt, Ru, Rh) were synthesized in water at 80 °C using sodium lignosulphonate as a reducing and stabilizing agent. They were characterized by TEM and XRD techniques: Pd NPs were larger (21 nm) and spherical in shape; Pt NPs were irregular; Ru and Rh NPs were smallest (1.9 and 5.3 nm, respectively). M NPs were tested as catalyst in the hydrogenation reactions of dicarboxylic acids (fumaric, malonic, trans,trans- and cis,cis-muconic acids) in water at room pressure and temperature. The NPs transformed selectively fumaric and malonic acids to succinic acid, although with different yields. Ru and Pt NPs were moderately active while with Pd NPs, 80% of succinic acid was obtained and with Rh NPs, 100% was observed. Carrying out the hydrogenations on muconic acids at pH 5, the formation of adipic acid was observed with all NPs but selectivities in the presence of Ru, Pt and Pd NPs were not excellent. The selectivity with Rh NPs was remarkable (86% from cis,cis- and about 100% from trans,trans-muconic acid) considering the mild conditions; furthermore, it is attractive that the adipic acid was obtained also from the cis,cis isomer which can be produced from biomass