A Biotracing Model of Salmonella in the Pork Production Chain

2012 ◽  
Vol 75 (2) ◽  
pp. 270-280 ◽  
Author(s):  
J. H. SMID ◽  
L. HERES ◽  
A. H. HAVELAAR ◽  
A. PIELAAT

In biotracing systems, downstream chain information and model-based approaches are used to trace the sources of microbial contamination in a food chain. This article includes the results of a biotracing model for Salmonella in the pork slaughter process chain. A Bayesian belief network model was used in which information on the Salmonella level at different locations in the slaughterhouse were used in combination with prior knowledge about the dynamics of Salmonella throughout the slaughter line. Data collected in a Dutch slaughterhouse were used to specify prior beliefs about the model inputs and to iteratively refine the distributions of the parameters in the model to obtain an optimal description of that specific slaughterhouse. The primary purpose of the model is to trace the sources of contamination for individual Salmonella-positive carcasses at the end of the slaughter line. The model results indicated that house flora on or in the carcass splitter was the source of contamination for many carcasses, especially for those that carried contamination on the cutting side. The results also indicated that the parameter values of the model may be subject to temporal variation and can be used as a tool to provide estimates of such trends. This model illustrates the concept of biotracing, gives insight into the dynamics of Salmonella in the slaughter line, and indicates the sites in the line where data collection is most effective for biotracing. This biotracing model was implemented as an interactive computer application, which is a step in the process toward an operational biotracing system by which a stakeholder can initiate immediate responses to Salmonella contamination and other hazards in the pork slaughterhouse.

Author(s):  
Benjamin Zwirzitz ◽  
Stefanie Urimare Wetzels ◽  
Beate Pinior ◽  
Evelyne Mann

2021 ◽  
Author(s):  
Manos Tsakiris ◽  
Neza Vehar ◽  
Stephen M Fleming ◽  
Sophie De Beukelaer ◽  
Max Rollwage

Updating one’s beliefs about the causes and effects of climate change is crucial for altering attitudes and behaviours. Importantly, metacognitive abilities - insight into the (in)correctness of one’s beliefs- play a key role in the formation of polarized beliefs. We investigated the role of domain-general and domain-specific metacognition in updating prior beliefs about climate change across the spectrum of climate change scepticism. We also considered the role of how climate science is communicated in the form of textual or visuo-textual presentations. We show that climate change scepticism is associated with differences in domain-general as well as domain-specific metacognitive abilities. Moreover, domain-general metacognitive sensitivity influenced belief updating in an asymmetric way : lower domain-general metacognition decreased the updating of prior beliefs, especially in the face of negative evidence. Our findings highlight the role of metacognitive failures in revising erroneous beliefs about climate change and point to their adverse social effects.


2020 ◽  
Vol 17 (3) ◽  
pp. 194-201
Author(s):  
Cibeli Viana ◽  
Mallu Jagnow Sereno ◽  
Luciano dos Santos Bersot ◽  
Jalusa Deon Kich ◽  
Luís Augusto Nero

2018 ◽  
Vol 38 (3) ◽  
pp. 393-399 ◽  
Author(s):  
Débora D.S. Gobbi ◽  
Maria G. Spindola ◽  
Luisa Z. Moreno ◽  
Carlos E.C. Matajira ◽  
Maria G.X. Oliveira ◽  
...  

ABSTRACT: Arcobacter is an emerging zoonotic pathogen, and the major transmission routes to humans are the handling or consumption of contaminated raw/undercooked food products of animal origin, water and seafood. The isolation and identification of Arcobacter species are not routine in clinical laboratories; therefore, its true incidence in human infections may be underestimated. The present study aimed to isolate and characterize Arcobacter from carcasses and fecal samples collected at swine slaughterhouses and from meat markets in São Paulo State, Brazil. The isolates were identified using multiplex-PCR to differentiate the species and analyzed by single-enzyme amplified fragment length polymorphism (SE-AFLP). Arcobacter spp. were isolated from 73.0% of swine carcasses, 4% of fecal samples and 10% of pork samples. A. butzleri was the most prevalent species identified, followed by A. cryaerophilus. Interestingly, the carcasses presented higher frequency of A. butzleri isolation, whereas only A. cryaerophilus was isolated from fecal samples. SE-AFLP enabled the characterization of A. butzleri and A. cryaerophilus into 51 and 63 profiles, respectively. The great genetic heterogeneity observed for both species corroborates previous reports. This study confirms the necessity for a standard isolation protocol and the improvement of molecular tools to further elucidate Arcobacter epidemiology.


2018 ◽  
Vol 190 ◽  
pp. 15013 ◽  
Author(s):  
Anastasiya Toenjes ◽  
Julien Kovac ◽  
Bernd Koehler ◽  
Axel von Hehl ◽  
Andreas Mehner ◽  
...  

Today, micro components are used in various industrial sectors such as electronics engineering and medical applications. The final quality of such parts depends on each individual step of the production chain from the manufacturing of semi-finished parts to the post-processing. In this study, magnetron sputtering is used to manufacture thin (15-30 μm) aluminium-zirconium alloy foils for the deep drawing of high strength and hardenable micro cups, which can be, for example, employed as micro valve caps. The development of a novel process chain for the production of these parts includes four different steps, beginning with the production of Al-Zr foils by magnetron sputtering. Secondly, tensile tests are performed with the foils in order to estimate their mechanical properties. Subsequently, micro deep drawing is used to produce the cup’s shape, and finally, a heat treatment in a drop-down tube furnace adjusts the cup’s hardness during fall. It is shown in particular that Al-Zr foils produced by magnetron sputtering have an attractive cold forming and hardening potential due to a microstructure consisting essentially of an oversaturated solid solution of zirconium in the aluminium matrix. This material state enables adequate formability and simplifies the heat treatment process since no solution annealing is required.


2016 ◽  
Vol 79 (7) ◽  
pp. 1197-1209 ◽  
Author(s):  
NORMA HEREDIA ◽  
CINDY CABALLERO ◽  
CARMEN CÁRDENAS ◽  
KARINA MOLINA ◽  
RAFAEL GARCÍA ◽  
...  

ABSTRACT To compare microbiological indicator and pathogen contamination among different types of fresh produce and environmental samples along the production chain, 636 samples of produce (rinsates from cantaloupe melons, jalapeño peppers, and tomatoes) and environmental samples (rinsates from hands of workers, soil, and water) were collected at four successive steps in the production process (from the field before harvest through the packing facility) on 11 farms in northern Mexico during 2011 and 2012. Samples were assayed for enteric pathogens (Escherichia coli O157:H7, other Shiga toxigenic E. coli, Salmonella, and Listeria monocytogenes) and microbial indicators (coliforms, other E. coli strains, and Enterococcus spp.). Salmonella was the only pathogen detected; it was found in one preharvest jalapeño sample (detection limits: 0.0033 CFU/ml in produce and hand samples, 0.0013 CFU/ml in water, and 0.04 CFU/g in soil). Microbial indicator profiles for produce, worker hands, and soil from jalapeño and tomato farms were similar, but cantaloupe farm samples had higher indicator levels (P < 0.05 for all comparisons) on fruit (6.5, 2.8, and 7.2 log CFU per fruit) and hands (6.6, 3.1, and 7.1 log CFU per hand) for coliforms, E. coli, and Enterococcus, respectively, and lower E. coli levels in soil (<1 CFU/g). In water from tomato farms, E. coli indicators were significantly more prevalent (70 to 89% of samples were positive; P = 0.01 to 0.02), and geometric mean levels were higher (0.3 to 0.6 log CFU/100 ml) than those in cantaloupe farm water (32 to 38% of samples were positive, geometric mean <1 CFU/100 ml). Microbial indicators were present during all production steps, but prevalence and levels were generally highest at the final on-farm production step (the packing facility) (P < 0.03 for significant comparisons). The finding that microbial contamination on produce farms is influenced by produce type and production step can inform the design of effective approaches to mitigate microbial contamination.


2007 ◽  
Vol 70 (1) ◽  
pp. 119-124 ◽  
Author(s):  
SIGRID MAYRHOFER ◽  
KONRAD J. DOMIG ◽  
ERNST AMTMANN ◽  
ANGELA H. A. M. van HOEK ◽  
AGNES PETERSSON ◽  
...  

The widespread use of antimicrobial substances has led to resistant populations of microorganisms in several ecosystems. In animal husbandry, the application of antibiotics has contributed to resistance development in pathogenic and commensal bacteria. These strains or their resistance genes can be spread along several ecological routes, including the food chain. Antibiotic resistance is important in terms of the safety of industrial strains, such as probiotics for food and feed. Bifidobacterium thermophilum and Bifidobacterium pseudolongum are known to comprise the major part of the bifidobacterial microbiota in the gut and feces of cattle and pigs. In this study, the antimicrobial susceptibility in bifidobacterial isolates of these species was investigated. Isolates from the beef and pork production chain were identified and typed to strain level, and the antimicrobial susceptibility level was tested to a set of antibiotics. Isolates with low susceptibility levels were screened by PCR for already described resistance genes. Strains atypically resistant to clindamycin, erythromycin, and tetracycline were determined. The resistance genes tet(O), tet(W), and erm(X) were detected in the bifidobacterial species that were examined.


2016 ◽  
Vol 7 ◽  
Author(s):  
Rocío Colello ◽  
María E. Cáceres ◽  
María J. Ruiz ◽  
Marcelo Sanz ◽  
Analía I. Etcheverría ◽  
...  

2020 ◽  
Vol 83 (3) ◽  
pp. 485-490 ◽  
Author(s):  
DANILO A. L. SILVA ◽  
CLARISSE V. BOTELHO ◽  
BRUNA T. F. MARTINS ◽  
RAFAELA M. TAVARES ◽  
ANDERSON C. CAMARGO ◽  
...  

ABSTRACT Listeria monocytogenes contamination was assessed in different steps of a pork production chain. Ten lots of pigs were sampled at termination barns, at slaughter (after bleeding, after buckling, after evisceration, and after final washing), at processing (knives, deboning tables, and employees' hands), and of end products (ribs, shoulder, ham, and sausage). All samples (n = 670) were subjected to L. monocytogenes detection, and the obtained isolates (n = 18, identified as Listeria spp.) were characterized by their biochemical characteristics, serogroups, virulence genes, pulsed-field gel electrophoresis profiles, antibiotic resistances (ampicillin, penicillin, gentamicin, and sulfamethoxazole-trimethoprim), and adhesion abilities. The results revealed the low occurrence of Listeria spp. in the evaluated pork production chain. However, four tested sausage samples (40%) were positive for Listeria spp., with L. monocytogenes identified in two (20%) of these samples. Ten isolates were identified as L. monocytogenes (eight from serogroup 1/2a or 3a and two from serogroup 4b, 4d, or 4e): all isolates were also positive for the virulence-related genes hlyA, iap, plcA, actA, inlA, inlB, inlC, and inlJ and susceptible to the tested antibiotics. One sausage sample was contaminated by both serogroups 1/2a or 3a and 4b, 4d, or 4e. Isolates from serogroup 1/2a or 3a obtained during visits 5 and 6 presented distinct genetic profiles by pulsed-field gel electrophoresis, indicating that contamination may come from different sources. The adhesion potential exhibited by Listeria spp. isolates (n = 18) ranged from weak (serogroup 4b, 4d, or 4e) to moderate (L. innocua and L. monocytogenes serogroup 1/2a or 3a). Despite the low occurrence of L. monocytogenes, pathogenic serogroups were detected in sausages, demanding control measures by the industry. HIGHLIGHTS


2012 ◽  
Vol 75 (4) ◽  
pp. 671-681 ◽  
Author(s):  
KEVIN HOLVOET ◽  
LIESBETH JACXSENS ◽  
IMCA SAMPERS ◽  
MIEKE UYTTENDAELE

This study provided insight into the degree of microbial contamination in the processing chain of prepacked (bagged) lettuce in two Belgian fresh-cut produce processing companies. The pathogens Salmonella and Listeria monocytogenes were not detected. Total psychrotrophic aerobic bacterial counts (TPACs) in water samples, fresh produce, and environmental samples suggested that the TPAC is not a good indicator of overall quality and best manufacturing practices during production and processing. Because of the high TPACs in the harvested lettuce crops, the process water becomes quickly contaminated, and subsequent TPACs do not change much throughout the production process of a batch. The hygiene indicator Escherichia coli was used to assess the water management practices in these two companies in relation to food safety. Practices such as insufficient cleaning and disinfection of washing baths, irregular refilling of the produce wash baths with water of good microbial quality, and the use of high product/water ratios resulted in a rapid increase in E. coli in the processing water, with potential transfer to the end product (fresh-cut lettuce). The washing step in the production of fresh-cut lettuce was identified as a potential pathway for dispersion of microorganisms and introduction of E. coli to the end product via cross-contamination. An intervention step to reduce microbial contamination is needed, particularly when no sanitizers are used as is the case in some European Union countries. Thus, from a food safety point of view proper water management (and its validation) is a critical point in the fresh-cut produce processing industry.


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