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Inshell walnuts collected from California walnut handlers over four harvests were evaluated for the presence of Escherichia coli 0157:H7 and Salmonella. E. coli 0157:H7 was not detected in any of 2,903 375-g samples evaluated in 2011, 2012, and 2013 (<0.034% prevalence; 95% confidence interval [Cl], 0 to 0.13%). Salmonella was not isolated from any of the 935 samples in 2010 (100 g evaluated; <0.11% prevalence; 95% Cl, 0 to 0.41%) but was isolated from 2 of 905 (375 g; 0.22% prevalence; 95% Cl, 0.061 to 0.80%), 1 of 998 (375 g; 0.10% prevalence; 95% Cl, 0.018 to 0.56%), and 1 of 1,000 (375 g; 0.10% prevalence; 95% Cl, 0.018 to 0.56%) samples in 2011, 2012, and 2013, respectively, for an average annual prevalence of 0.14% (375 g; 95% Cl, 0.054 to 0.35%). The levels of Salmonella in positive samples determined by a modified most-probable-number (MPN) method were estimated to be 0.32 to 0.42 MPN/100 g (95% Cl, 0.045 to 3.6 MPN/100 g). [ABSTRACT FROM AUTHOR]

Pathogens occurring in particulate foods may be unevenly distributed, which may impact interpretation of most-probable-number (MPN) values. The MPN analysis of Salmonella in naturally contaminated raw almonds was conducted using two sample preparation methods. Raw almond kernels (3,698 samples) and inshell almonds (455 samples) were collected from almond processors throughout California during the 2006 and 2007 harvests, and l00-g samples were enriched for Salmonella. The prevalence of Salmonella on kernels and inshell almonds was 1.6 and 0.9%, respectively, in 2006, and 0.83 and 2.2%, respectively, in 2007. Almond kernel samples from 2006 were further enriched for Salmonella, and levels of the organism were determined for positive samples by three-tube MPN analysis (25 g, 2.5 g, 0.25 g). Almonds were either divided into subsamples prior to blending and enrichment (method A), or samples were blended in enrichment broth prior to preparation of subsamples (method B). Salmonella was not isolated (<1.2 MPN/100 g) upon retesting of 19 of 31 (method A) or 23 of 29 (method B) positive samples. When detected, levels were 1.4 to 15.5 MPN/100 g (average 2.3 MPN/100 g) or 1.4 to 18.3 MPN/100 g (average 2.1 MPN/100 g) using methods A or B, respectively. A total of 23 different Salmonella serovars were identified from the original almond samples. Salmonella Muenchen was the most frequently isolated serovar (15%) from the 53 Salmonella-positive samples, followed by Newport (12%), Enteritidis (10%), and Typhimurium (8%). No correlation was found between presence of Salmonella and E. coli levels, aerobic plate counts, or counts of yeasts or molds. [ABSTRACT FROM AUTHOR]

Data on the prevalence and populations of pathogens in individual foods are critical to the development of product-specific quantitative microbial risk assessments. An outbreak of salmonellosis associated with the consumption of raw almonds in 2000 to 2001 provided an opportunity to evaluate the levels of Salmonella in the recalled product. Duplicate 100-g samples from each of fifty 22.7-kg boxes of recalled almonds were enriched by one of two methods. Salmonella was isolated by at least one method from 42 boxes (84% positive). The levels of Salmonella determined by a three-tube most-probable-number (MPN) method were 8.5 ± 1.3 MPN/100 g. In a subsequent study, raw almonds that arrived at almond processors were sampled from 2001 through 2005 to determine the overall prevalence and levels of Salmonella and to characterize the Salmonella isolates obtained. Aerobic plate counts, coliform counts, and MPN levels of Escherichia coli were also determined on positive samples. An isolation frequency for Salmonella of 81 (0.87% ± 0.2%) of 9,274 samples tested (100 g) was determined for raw almonds sampled from throughout California over the 5-year period. Salmonella was not isolated upon retesting in 59 of 65 positive samples. When detected, levels were 1.2 to 2.9 MPN/100 g. Of the 81 total isolates, 35 different serotypes of Salmonella were represented. Aerobic plate counts, coliform counts, and E. coli levels did not correlate with the presence of Salmonella. [ABSTRACT FROM AUTHOR]

Developing coordination complexes of earth abundant metals that can perform substrate oxidations under benign conditions is an ongoing challenge. Herein, the reactivity of two mononuclear Cu-complexes toward the oxidant H 2 O 2 is reported. Both complexes displayed ligand oxidation upon reaction with the oxidant. Analysis of spectroscopic data established that the respective product complexes contained mononuclear Cu(II) centers. Moreover, treatment of these Cu-complexes with oxidant in the presence of substrate resulted in the interception of ligand oxidation with preferential oxidation of the substrate. Computational studies identified plausible mechanistic pathways, suggesting a copper-oxyl intermediate as the likely reactive intermediate responsible for substrate and ligand oxidation. To our knowledge, this is the first Cu-mediated system that showed ligand oxidation, oxo-transfer capability, and external hydrocarbon oxidation under stoichiometric conditions. Mononuclear Cu-mediated hydrocarbon oxidation: reactivity of mononuclear copper system toward hydrogen peroxide/triethylamine and its ability to oxidize external substrates has been demonstrated. This is the first report of a system where ligand oxidation, oxo-transfer reaction and hydrocarbon oxidation was observed. Unlabelled Image • Reactivity of mononuclear Cu complexes with hydrogen peroxide/triethylamine is reported. • The presence of mononuclear Cu(II) centers was established spectroscopically. • Computational studies identified plausible mechanistic pathways. • Ligand oxidation, oxo transfer reaction and hydrocarbon oxidation were observed. [ABSTRACT FROM AUTHOR]

Abstract Here we present a new 4D printing technique capable of producing a diverse range of trilayer constructs using commercial low-cost desktop 3D printers. This unique methodology permits the viable construction of dynamically robust and complex origami architectures for a new generation of active structures. The resulting creations transform from flat 2D parts to 3D structures through submersion in water and return to their original configuration through dehydration. This technique uses commercially available materials and printers to enable a 4D printing method that is more accessible and affordable than previous examples of hydration triggered 4D printing. This method yields a controlled and predictable actuation route and final shape, enabling it to be used for both simple and complex origami inspired designs, such as the tessellated waterbomb origami pattern, a design that has not previously been realised with 4D printing. These new designs demonstrate how the integration of multiple trilayers into a single 3D print enables through-thickness control of actuation and resulting formation of active structures with complexity beyond what has previously been achieved with 4D printing. Graphical Abstract Highlights • Thermoplastic polyurethane hydrogel filament was manufactured and 3D-printed into multi-material structures. • A range of trilayer constructs with hydration-triggered hydrogel hinges were produced using low-cost desktop 3D printers. • The effect of varying hinge geometry on the final actuation angle and the transient actuation progression was investigated. • Complex tessellated origami structures were produced which had not been previously realised by 4D-printing. [ABSTRACT FROM AUTHOR]