Fate of Escherichia coli O145 present naturally in bovine slurry applied to vegetables before harvest, after washing and simulated wholesale and retail distribution

Aims: To determine the fate of E. coli on vegetables that were processed through commercial wash treatments and stored under simulated retail conditions at 4oC or wholesale at fluctuating ambient temperatures (0-25oC, dependent on season). Methods and Results: Bovine slurry that was naturally contaminated with Escherichia coli O145 was applied without dilution or diluted 1/10 using borehole water to growing potatoes, leeks or carrots. Manure was applied one week prior to harvest to simulate a near-harvest contamination event by manure deposition or an application of contaminated water to simulate a flooding event or irrigation from a contaminated water source. At harvest, crops were contaminated at up to two log cfu/g. Washing transferred E. coli into the water of a flotation tank used for potato washing and did not completely remove all traces of contamination from the crop. Manure contaminated potatoes were observed to contain 0.72 cfu E. coli O145/g after processing and retail storage. Manure-contaminated leeks harboured 0.73 – 1.55 cfu E. coli O145/g after washing and storage. There was no cross contamination when leeks were spray-washed. Washing in an abrasive drum resulted in less than perfect decontamination for manure-contaminated carrots. There were five post-distribution isolations from carrots irrigated with contaminated water 24h prior to harvest. Conclusions: Standard commercial washing and distribution conditions may be insufficient to reliably control human pathogenic E. coli on fresh produce. Significance and Impact: Previous speculation that the cause of a UK foodborne disease outbreak was soil from imperfectly cleaned vegetables is plausible

Modelling-based identification of factors influencing campylobacters in chicken broiler houses and on carcasses sampled after processing and chilling

Publication history: Accepted - 30 January 2017; Published online - 4 March 2017.Aims: To identify production and processing practices that might reduceCampylobacter numbers contaminating chicken broiler carcasses.Methods and Results: The numbers of campylobacters were determined oncarcass neck skins after processing or in broiler house litter samples.Supplementary information that described farm layouts, farming conditions forindividual flocks, the slaughterhouse layouts and operating conditions insideplants was collected, matched with each Campylobacter test result. Statisticalmodels predicting the numbers of campylobacters on neck skins and in litterwere constructed. Carcass microbial contamination was more stronglyinfluenced by on-farm production practices compared with slaughterhouseactivities. We observed correlations between the chilling, washing anddefeathering stages of processing and the numbers of campylobacters oncarcasses. There were factors on farm that also correlated with numbers ofcampylobacters in litter. These included bird gender, the exclusion of dogsfrom houses, beetle presence in the house litter and the materials used toconstruct the house frame.Conclusions: Changes in farming practices have greater potential for reducingchicken carcass microbial contamination compared with processinginterventions.Significance and Impact of the Study: Routine commercial practices wereidentified that were correlated with lowered numbers of campylobacters.Consequently, these practices are likely to be both cost-effective and suitablefor adoption into established farms and commercial processingThis work was funded by the United Kingdom Food Standards Agency (FSA) as projects FS241051A and FS101123

Molecular and Historical Aspects of Corn Belt Dent Diversity

Tens-of-thousands of open-pollinated cultivars of corn (Zea mays L.) are being maintained in germplasm banks. Knowledge of the amount and distribution of genetic variation within and among accessions can aid end users in choosing among them. We estimated molecular genetic variation and looked for influences of pedigree, adaptation, and migration in the genetic makeup of conserved Corn-Belt Dent-related germplasm. Plants sampled from 57 accessions representing Corn-Belt Dents, Northern Flints, Southern Dents, plus 12 public inbreds, were genotyped at 20 simple sequence repeat (SSR) loci. For 47 of the accessions, between 5 and 23 plants per accession were genotyped (mean = 9.3). Mean number of alleles per locus was 6.5 overall, 3.17 within accessions, and 3.20 within pooled inbreds. Mean gene diversity was 0.53 within accessions and 0.61 within pooled inbreds. Open-pollinated accessions showed a tendency toward inbreeding (FIS = 0.09), and 85% of genetic variation was shared among them. A Fitch-Margoliash tree strongly supported the distinctiveness of flint from dent germplasm but did not otherwise reveal evidence of genetic structure. Mantel tests revealed significant correlations between genetic distance and geographical (r = 0.54, P= 0.04) or maturity zone (r = 0.33, P = 0.03) distance only if flint germplasm was included in the analyses. A significant correlation (r = 0.76, P \u3c 0.01) was found between days to pollen shed and maturity zone of accession origin. Pedigree, rather than migration or selection, has most influenced the genetic structure of the extant representatives of the open-pollinated cultivars at these SSR loci

A Review of the fossil record of turtles of the clade Baenidae

The fossil record of the turtle clade Baenidae ranges from the Early Cretaceous (Aptian—Albian) to the Eocene. The group is present throughout North America during the Early Cretaceous, but is restricted to the western portions of the continents in the Late Cretaceous and Paleogene. No credible remains of the clade have been reported outside of North America to date. Baenids were warmadapted freshwater aquatic turtles that supported high levels of diversity at times through niche partitioning, particularly by adapting to a broad range of dietary preferences ranging from omnivorous to molluscivorous. Current phylogenies place Baenidae near the split of crown-group Testudines. Within Baenidae three more inclusive, named clades are recognized: Baenodda, Palatobaeninae and Eubaeninae. A taxonomic review of the group concludes that of 49 named taxa, 30 are nomina valida, 12 are nomina invalida and 7 are nomina dubia

Space Telescope and Optical Reverberation Mapping Project. VII. Understanding the Ultraviolet Anomaly in NGC 5548 with X-Ray Spectroscopy

During the Space Telescope and Optical Reverberation Mapping Project observations of NGC 5548, the continuum and emission-line variability became decorrelated during the second half of the six-month-long observing campaign. Here we present Swift and Chandra X-ray spectra of NGC 5548 obtained as part of the campaign. The Swift spectra show that excess flux (relative to a power-law continuum) in the soft X-ray band appears before the start of the anomalous emission-line behavior, peaks during the period of the anomaly, and then declines. This is a model-independent result suggesting that the soft excess is related to the anomaly. We divide the Swift data into on- and off-anomaly spectra to characterize the soft excess via spectral fitting. The cause of the spectral differences is likely due to a change in the intrinsic spectrum rather than to variable obscuration or partial covering. The Chandra spectra have lower signal-to-noise ratios, but are consistent with the Swift data. Our preferred model of the soft excess is emission from an optically thick, warm Comptonizing corona, the effective optical depth of which increases during the anomaly. This model simultaneously explains all three observations: the UV emission-line flux decrease, the soft-excess increase, and the emission-line anomaly

Isolamento e caratterizzazione di mutanti di Pseudomonas syringae pv. syringae difettivi nella produzione di siringopeptine

Convegno annuale della Società di Patologia vegetale, Problemi patologici e sanitari della conservazione delle derrate vegetali. Segnali nelle interazioni ospite-parassit