Diverse land use and the impact on (Irrigation) water quality and need for measures - A case study of a Norwegian river

Surface water is used for irrigation of food plants all over the World. Such water can be of variable hygienic quality, and can be contaminated from many different sources. The association of contaminated irrigation water with contamination of fresh produce is well established, and many outbreaks of foodborne disease associated with fresh produce consumption have been reported. The objective of the present study was to summarize the data on fecal indicators and selected bacterial pathogens to assess the level of fecal contamination of a Norwegian river used for irrigation in an area which has a high production level of various types of food commodities. Sources for fecal pollution of the river were identified. Measures implemented to reduce discharges from the wastewater sector and agriculture, and potential measures identified for future implementation are presented and discussed in relation to potential benefits and costs. It is important that the users of the water, independent of intended use, are aware of the hygienic quality and the potential interventions that may be applied. Our results suggest that contamination of surface water is a complex web of many factors and that several measures and interventions on different levels are needed to achieve a sound river and safe irrigation.publishedVersio

Occurrence of Escherichia coli, Campylobcter, Salmonella and Shiga-Toxin producing E. coli in Norwegian primary strawberry production

The aim of this study was to investigate the bacteriological quality of strawberries at harvest and to study risk factors such as irrigation water, soil and picker’s hand cleanliness. Four farms were visited during the harvest season in 2012. Samples of strawberries, irrigation water, soil and hand swabs were collected and analyzed for E. coli, Campylobacter, Salmonella and STEC Although fecal indicators and pathogens were found in environmental samples, only one of 80 samples of strawberries was positive for E. coli (1.0 log10 cfu/g) and pathogens were not detected in any of the strawberry samples. The water samples from all irrigation sources were contaminated with E. coli in numbers ranging from 0 to 3.3 log10 cfu/g. Campylobacter (8/16 samples) and Salmonella (1/16 samples) were isolated from samples with high numbers of E. coli. The water samples collected from a lake had lower numbers of E. coli than the samples from rivers and a stream. The present study indicated continuous background contamination in the primary production environment. Although the background contamination was not reflected on the strawberries tested here, the results must be interpreted with caution due to the limited number of samples

The prevalence and genomic context of Shiga toxin 2a genes in E. coli found in cattle.

Shiga toxin-producing Escherichia coli (STEC) that cause severe disease predominantly carry the toxin gene variant stx2a. However, the role of Shiga toxin in the ruminant reservoirs of this zoonotic pathogen is poorly understood and strains that cause severe disease in humans (HUSEC) likely constitute a small and atypical subset of the overall STEC flora. The aim of this study was to investigate the presence of stx2a in samples from cattle and to isolate and characterize stx2a-positive E. coli. In nationwide surveys in Sweden and Norway samples were collected from individual cattle or from cattle herds, respectively. Samples were tested for Shiga toxin genes by real-time PCR and amplicon sequencing and stx2a-positive isolates were whole genome sequenced. Among faecal samples from Sweden, stx1 was detected in 37%, stx2 in 53% and stx2a in 5% and in skin (ear) samples in 64%, 79% and 2% respectively. In Norway, 79% of the herds were positive for stx1, 93% for stx2 and 17% for stx2a. Based on amplicon sequencing the most common stx2 types in samples from Swedish cattle were stx2a and stx2d. Multilocus sequence typing (MLST) of 39 stx2a-positive isolates collected from both countries revealed substantial diversity with 19 different sequence types. Only a few classical LEE-positive strains similar to HUSEC were found among the stx2a-positive isolates, notably a single O121:H19 and an O26:H11. Lineages known to include LEE-negative HUSEC were also recovered including, such as O113:H21 (sequence type ST-223), O130:H11 (ST-297), and O101:H33 (ST-330). We conclude that E. coli encoding stx2a in cattle are ranging from strains similar to HUSEC to unknown STEC variants. Comparison of isolates from human HUS cases to related STEC from the ruminant reservoirs can help identify combinations of virulence attributes necessary to cause HUS, as well as provide a better understanding of the routes of infection for rare and emerging pathogenic STEC

Slaughter hygiene in European cattle and sheep abattoirs assessed by microbiological testing and Hygiene Performance Rating

The aim of this study was to describe slaughter hygiene in a selection of ovine and bovine abattoirs in Europe, as assessed by microbiological testing and Hygiene Performance Rating (HPR) audits, and to compare the results obtained by these different approaches. Two types of microbiological testing were used: standardized study testing, which was similar in all abattoirs, and the abattoirs' own mandatory microbiological testing. Ten cattle slaughter lines were visited in Norway, Denmark, Germany, and Spain and 10 sheep slaughter lines were visited in Norway, UK, and Spain. HPR scores were obtained for each operation along the slaughter line and summed up into a total score (%). For the standardized study testing, gauze-cloth swabbing of approximately 800 cm2 of cattle carcasses and 600 cm2 of sheep carcasses was used on 25 warm carcasses at each slaughter line. In contrast, the mandatory microbiological testing conducted by the abattoirs used different types of equipment, methods, and analyses. Higher mean counts of Enterobacteriaceae and E. coli were obtained from sheep carcasses (−0.6 and −0.9 log CFU/cm2, respectively) than from cattle carcasses (−1.4 and −2.5 log CFU/cm2, respectively), and the numbers of E. coli detected on cattle carcasses were particularly low. A close relationship was found between the total HPR score and the Enterobacteriaceae and E. coli results obtained by the standardized study testing. For cattle, R2 values were 0.69 and 0.62 for Enterobacteriaceae and E. coli, respectively, and for sheep the equivalent values were 0.62 and 0.60. The correlations between the HPR results and the microbiological results from the abattoirs’ mandatory sampling were low, which could reflect fact that in 90% of the samples, bacteria tested were below the limit of detection with the methods used. This study reports the methodology and results from the first European baseline study on slaughter hygiene. The correlation between the HPR results and the standardized study testing of the carcasses suggests that HPR could be a useful proxy measure for improving slaughter hygiene and risk management.publishedVersio

Slaughter hygiene in European cattle and sheep abattoirs assessed by microbiological testing and Hygiene Performance Rating

The aim of this study was to describe slaughter hygiene in a selection of ovine and bovine abattoirs in Europe, as assessed by microbiological testing and Hygiene Performance Rating (HPR) audits, and to compare the results obtained by these different approaches. Two types of microbiological testing were used: standardized study testing, which was similar in all abattoirs, and the abattoirs' own mandatory microbiological testing. Ten cattle slaughter lines were visited in Norway, Denmark, Germany, and Spain and 10 sheep slaughter lines were visited in Norway, UK, and Spain. HPR scores were obtained for each operation along the slaughter line and summed up into a total score (%). For the standardized study testing, gauze-cloth swabbing of approximately 800 cm2 of cattle carcasses and 600 cm2 of sheep carcasses was used on 25 warm carcasses at each slaughter line. In contrast, the mandatory microbiological testing conducted by the abattoirs used different types of equipment, methods, and analyses. Higher mean counts of Enterobacteriaceae and E. coli were obtained from sheep carcasses (−0.6 and −0.9 log CFU/cm2, respectively) than from cattle carcasses (−1.4 and −2.5 log CFU/cm2, respectively), and the numbers of E. coli detected on cattle carcasses were particularly low. A close relationship was found between the total HPR score and the Enterobacteriaceae and E. coli results obtained by the standardized study testing. For cattle, R2 values were 0.69 and 0.62 for Enterobacteriaceae and E. coli, respectively, and for sheep the equivalent values were 0.62 and 0.60. The correlations between the HPR results and the microbiological results from the abattoirs’ mandatory sampling were low, which could reflect fact that in 90% of the samples, bacteria tested were below the limit of detection with the methods used. This study reports the methodology and results from the first European baseline study on slaughter hygiene. The correlation between the HPR results and the standardized study testing of the carcasses suggests that HPR could be a useful proxy measure for improving slaughter hygiene and risk management

Risk assessment of import and dissemination of intestinal pathogenic bacteria via fresh herbs and leafy vegetables from South-East Asia. Opinion of the Panel on Biological Hazards

publishedVersio

An Official Outbreak Investigation of Acute Haemorrhagic Diarrhoea in Dogs in Norway Points to Providencia alcalifaciens as a Likely Cause

An outbreak investigation was initiated in September 2019, following a notification to the Norwegian Food Safety Authority (NFSA) of an unusually high number of dogs with acute haemorrhagic diarrhoea (AHD) in Oslo. Diagnostic testing by reporting veterinarians had not detected a cause. The official investigation sought to identify a possible common cause, the extent of the outbreak and prevent spread. Epidemiological data were collected through a survey to veterinarians and interviews with dog owners. Diagnostic investigations included necropsies and microbiological, parasitological and toxicological analysis of faecal samples and food. In total, 511 dogs with acute haemorrhagic diarrhoea were registered between 1 August and 1 October. Results indicated a common point source for affected dogs, but were inconclusive with regard to common exposures. A notable finding was that 134 of 325 faecal samples (41%) cultured positive for Providencia alcalifaciens. Whole genome sequencing (WGS) of 75 P. alcalifaciens isolates from 73 dogs revealed that strains from 51 dogs belonged to the same WGS clone. Findings point to P. alcalifaciens as implicated in the outbreak, but investigations are needed to reveal the pathogenic potential of P. alcalifaciens in dogs and its epidemiology