Detection and quantification of human and bovine novoviruses by a TaqMan RT-PCR assay with a control for inhibition.
Scipioni, Alexandra ; ; Mauroy, Axel et al
in Molecular and Cellular Probes (2008), 22
Noroviruses are single-stranded RNA viruses belonging to the family Caliciviridae. They are a major cause of epidemic and sporadic gastroenteritis in humans and calves. Reverse transcription-polymerase ... [more ▼]
Noroviruses are single-stranded RNA viruses belonging to the family Caliciviridae. They are a major cause of epidemic and sporadic gastroenteritis in humans and calves. Reverse transcription-polymerase chain reaction (RT-PCR) has become the ‘‘gold standard’’ for detection of noroviruses in faecal and environmental samples. However, false negative results due to co-concentration of RT-PCR inhibitors are a continuous concern. A TaqMan real-time RT-PCR assay making use of a foreign internal RNA control and a RNA standard was developed. Very interestingly, this method is capable of detecting human noroviruses belonging to genogroups I and II, and bovine noroviruses belonging to genogroup III. Inhibitors were removed efficiently by 1/10 dilution of the sample or addition of bovine serum albumin to the RT-PCR mix. This assay was validated with human and bovine stool samples previously tested for norovirus by conventional RT-PCR. The ability to detect norovirus in stool samples that were negative by conventional RT-PCR assay demonstrate the higher sensitivity of the TaqMan assay compared to the conventional RT-PCR assay. This real-time RT-PCR assay allows the detection of both human and bovine noroviruses, avoids false negative results and is able to quantify the level of norovirus contamination. [less ▲]Detailed reference viewed: 72 (19 ULg)
Bifidobacteria as indicators of faecal contamination along a sheep meat production chain
Delcenserie, Véronique ; ; et al
in Journal of Applied Microbiology (2008), 104(1), 276-284
Aims: The potential use of bifidobacteria as indicators for faecal contamination was studied along a sheep meat production and processing chain. The levels of bifidobacteria were compared with those of ... [more ▼]
Aims: The potential use of bifidobacteria as indicators for faecal contamination was studied along a sheep meat production and processing chain. The levels of bifidobacteria were compared with those of Escherichia coli. Total viable counts were followed along the chain (244 samples). Methods and Results: Forty-three per cent of the samples contained bifidobacteria, of which 15% were solely detected using a PCR method based on the hsp60 gene and not by a culture-based method. Bifidobacteria were detected in only three of nine sheep faeces samples using one or the other method. However, carcasses (types C and E) were highly contaminated. These sample types (30% and 28%, respectively) were positive for bifidobacteria and negative for E. coli. The species Bifidobacterium pseudolongum and Bif. thermophilum, isolated from faecal samples, were predominant. Bifidobacterium choerinum were found in C, D, E and F sample types. Conclusions: Bifidobacteria were shown more efficient than E. coli in carcasses samples. The presence of Bif. choerinum suggested a faecal pork contamination. Significance and Impact of the Study: Detection and identification of bifidobacteria, in correlation with E. coli counting, should improve hygiene quality of mutton processing chains. [less ▲]Detailed reference viewed: 97 (19 ULg)
Detection of Neospora caninum in dog organs using real time PCR systems.
; Losson, Bertrand ; Daube, Georges et al
in Veterinary Parasitology (2008), 155
Neospora caninum is a parasite responsible for paresis in dogs. The dog can harbour enkysted parasites in several organs. The detection of N. caninum was performed using 3 different real time PCR systems ... [more ▼]
Neospora caninum is a parasite responsible for paresis in dogs. The dog can harbour enkysted parasites in several organs. The detection of N. caninum was performed using 3 different real time PCR systems all amplifying the NC5 DNA region. One system was based on Sybr1green, one on PlexorTM technology and the last on Taqman1 probe. Comparison of the three methods indicated that the detection limit was 1 equivalent genome on pure DNA but that this detection limit increased in the presence of foreign DNA using the Sybrgreen and Plexor systems. Therefore, the Taqman system was chosen to detect N. caninum in liver and spleen of naturally infected dogs. The overall prevalence was 32.2%. Comparison between PCR results and serological results using IFAT showed that among the 28 PCR positive dogs only 9 were seropositive and that 8 seropositive dogs were PCR negative. Therefore serology can underestimate the real carriage in dogs. However, PCR methods must be improved in terms of sensitivity and inhibition problems. [less ▲]Detailed reference viewed: 78 (4 ULg)
Botulisme bij melkvee : voedselveiligheidsaspecten en maatregelen.
; ; et al
in Vlaams Diergeneeskundig Tijdschrift (2008), 78
aar aanleiding van enkele uitbraken van botulisme bij melkvee in België gedurende de laatste jaren worden in dit artikel de voedselveiligheidsaspecten die daaraan verbonden zijn nader besproken evenals de ... [more ▼]
aar aanleiding van enkele uitbraken van botulisme bij melkvee in België gedurende de laatste jaren worden in dit artikel de voedselveiligheidsaspecten die daaraan verbonden zijn nader besproken evenals de maatregelen die kunnen genomen worden op het melkveebedrijf en in de voedselketen ter vrijwaring van de blootstelling van de consument aan eventuele gezondheidsrisico’s. Uit een kwalitatieve risicoevaluatieis gebleken dat het risico op overdracht van botulismetoxinen via verwerkte melk naar de consument zeer laag is. De fecale contaminatie van de uier en melk door Clostridium botulinum sporen kan in geval van type B daarentegen een risico op de ontwikkeling van botulisme bij gevoelige mensen vormen. Bovendien kunnen in rauwe en laag verhitte melk- en zuivelproducten toxinen worden geproduceerd na de ontkieming van deze sporen. [less ▲]Detailed reference viewed: 92 (1 ULg)
Hygiene indicator microorganisms for selected pathogens on beef, pork and poultry meats in Belgium.
; ; et al
in Journal of Food Protection (2008), 71
Several bacterial indicators are used to evaluate the hygiene of the meat slaughtering process. The objectives of this study were to assess the Belgian baseline of hygienic indicators and the relationship ... [more ▼]
Several bacterial indicators are used to evaluate the hygiene of the meat slaughtering process. The objectives of this study were to assess the Belgian baseline of hygienic indicators and the relationship between the indicators and zoonotic agents, in order to establish hygiene indicator criteria for carcasses and meat of beef, pork and poultry. The study used the results from the official Belgian surveillance plan from 2000 to 2003, which included the monitoring of counts for E. coli (ECC), Enterobacteriaceae (EC), aerobic colonies (ACC) and Pseudomonas. The sampling method was the wet and dry swabbing technique for beef and pork carcasses, and neck skin excision for chicken and layer carcasses. The 75th and 95th percentiles of ECC were –0.20 and 0.95 log cfu/cm2 for beef carcasses, 1.20 and 2.32 log cfu/cm2 for pork carcasses, and 4.05 and 5.24 log cfu/g for chicken carcasses. The aerobic colony counts were between 2.1 and 4.5 log cfu/cm2 or /g higher than those of ECC for cattle, pork and poultry. For beef and pork carcasses, a significant correlation between ECC, EC and ACC was shown between each parameter. ECC (for pork and beef samples), and EC (in pork carcasses) were detected at significantly higher levels in samples contaminated with Salmonella. In poultry samples, ECC were in general higher for samples containing Salmonella or Campylobacter. This study showed that E. coli may be considered as a good indicator for enteric zoonotic agents such as Salmonella for beef, pork and poultry, and Campylobacter in poultry meat samples. [less ▲]Detailed reference viewed: 180 (6 ULg)
Comparison between swabbing and destructive methods for microbiological pig carcass sampling.
; Daube, Georges
in Letters in Applied Microbiology (2008), 47
Aims: To compare the Belgian swabbing sampling method for pig carcasses with the reference destructive method with regard to Escherichia coli and aerobic plate counts, Salmonella and Campylobacter ... [more ▼]
Aims: To compare the Belgian swabbing sampling method for pig carcasses with the reference destructive method with regard to Escherichia coli and aerobic plate counts, Salmonella and Campylobacter prevalence and their relationship. Methods and Results: Recovery was significantly lower for the swabbing method and corresponded to a recovery of 36% for E. coli counts and 81% for aerobic plate counts in comparison with the destructive method. There was no significant difference between the swabbing and destructive sampling methods for the prevalence of Salmonella or Campylobacter. A higher median for E. coli counts was detected for samples where Salmonella or Campylobacter were detected. The same association was also observed between the median for aerobic plate counts and the presence of Campylobacter. Conclusions: The method of swabbing used, covering 600 cm2 on each half-pig carcass, is efficient for the sampling of pig carcasses in comparison with the reference destructive method. Significance and Impact of the Study: This study describes an efficient method for microbiological pig carcass sampling. The Belgian swabbing method should continue to be used to allow the follow up of bacterial contamination in the Belgian meat production chain. [less ▲]Detailed reference viewed: 37 (5 ULg)
L'évaluation quantitative du risque microbiologique: revue de trois modèles liés à Salmonella dans les aliments.
Delhalle, Laurent ; Saegerman, Claude ; Farnir, Frédéric et al
in Annales de Médecine Vétérinaire (2008), 152
Following international agreements and european legislation, risk analysis has become a systematic approach to control the food chain safety. The microbial risks in the food chain and their consequences ... [more ▼]
Following international agreements and european legislation, risk analysis has become a systematic approach to control the food chain safety. The microbial risks in the food chain and their consequences for public health can be assessed and managed more effectively. This paper gives a general description of the risk analysis principles based on the Codex Alimentarius commission. This work highlights the advantages and disadvantages of risk analysis and also treats the problems to achieve a complete “farm to fork” model. Salmonella in different food types is taken as an example to illustrate quantitative risk assessment. Two models concerning eggs and broiler chickens developed by the World Health Organization/Food and Agriculture Organization consortium and a third model concerning pigs developed by the Veterinary Laboratories Agency of the United Kingdom are described. An analysis of the methods used for the construction of these two models is also presented. The interest of these three models is that they also include risk management options to limit the spread of food-borne infections. They also describe the final risk for a population following consumption of foodstuffs. These models are valuable tools for health officials but also for feed industry. [less ▲]Detailed reference viewed: 212 (24 ULg)
Etude de la variabilité de la qualité de la viande de porc par analyse en composantes principales
Leroy, Bernadette ; ; et al
in Sciences des Aliments (2008), 28(6), 451-468
Study of the variability of pork quality by Principal Component Analysis (PCA) Principal component analysis (PCA) was performed to study the relationships between technological, organoleptic ... [more ▼]
Study of the variability of pork quality by Principal Component Analysis (PCA) Principal component analysis (PCA) was performed to study the relationships between technological, organoleptic, microbiological and zootechnic variables, measured on 264 pigs belonging to different Belgian production systems. The four first principal components explained 63 % of the total variability. The variables such as the pH, the electrical conductivity, the brightness and the color of meat presented the best correlation with the first principal component whereas the variables such as the E. coli Count and the Total Viable Count measured on the carcass, the hot carcass weight and the cooking loss of meat presented the best correlation with the second principal component. The first principal component was defined as an axis of technological and organoleptic quality whereas the second was defined as a microbiological axis. PCA allowed to differentiate two groups in terms of technological and organoleptic properties. A group including samples belonged to the first quality production chain and a part of samples belonged to the second was separated from the principal group by a lower pH, measured 45 minutes post mortem, and a paler meat. [less ▲]Detailed reference viewed: 80 (12 ULg)
Risk factors for Salmonella and hygiene indicators in the 10 largest Belgian pig slaughterhouses.
Delhalle, Laurent ; ; et al
in Journal of Food Protection (2008), 77
A survey was conducted to collect data on Salmonella prevalence, Escherichia coli counts (ECCs), and aerobic bacteria colony counts (ACCs) on pig carcasses after chilling at the 10 largest Belgian pig ... [more ▼]
A survey was conducted to collect data on Salmonella prevalence, Escherichia coli counts (ECCs), and aerobic bacteria colony counts (ACCs) on pig carcasses after chilling at the 10 largest Belgian pig slaughterhouses during 2000 through 2004. Potential risk factors of contamination associated with production parameters, technical descriptions of the installations, and cleaning and disinfection methods were assessed during investigations in the slaughterhouses. These variables were used first in a univariate analysis and then were extended to a multivariate analysis with a logistic mixed regression model for Salmonella and a linear mixed model for ECCs and ACCs with slaughterhouses as the random effect. The results indicated high variability concerning Salmonella contamination among the 10 slaughterhouses, with prevalence ranging from 2.6 to 34.3% according to the area of origin. The median ECC and median ACC ranged from 0.43 to 1.11 log CFU/cm2 and from 2.37 to 3.65 log CFU/cm2, respectively. The results of the logistic and linear regressions revealed that some working practices such as scalding with steam, second flaming after polishing, and complete cleaning and disinfection of the splitting machine several times a day were beneficial for reducing Salmonella prevalence, ECCs, and ACCs. Changing the carcass hooks just before chilling, using water as the cleaning method, and a higher frequency of disinfection of the lairage seemed to be protective against E. coli in the multivariate mixed linear model. The monitoring of critical points, slaughterhouse equipment, good slaughtering practices, and effective washing and disinfection are the keys to obtaining good microbiological results. [less ▲]Detailed reference viewed: 78 (13 ULg)
Development of Diagnostic DNA Microarray for the Simultaneous Detection of Multiple Viral Pathogens Affecting Aquacultured Finfish and Shellfish
; Daube, Georges ;
Poster (2007, November)Detailed reference viewed: 13 (0 ULg)
Probabilistische blootstellingschatting van de Belgische consument aan Listeria monocytogenes door consumptiez van gerookte zalm: een combinatie van het gebruik van de databanken van de controleprogramma van het FAVV en de consumptiepelling.
; ; Daube, Georges et al
Conference (2007, November)Detailed reference viewed: 11 (1 ULg)
Utilisation d'une nouvelle espèce de Bifidobacterium (Bifidobacterium vercosense) à effets probiotiques
Daube, Georges ; ; Delcenserie, Véronique et al
Patent (2007)Detailed reference viewed: 164 (20 ULg)
Salmonella spp on the pig meat through the cold chain in Belgium
Delhalle, Laurent ; ; Daube, Georges
Poster (2007, June)Detailed reference viewed: 1 (0 ULg)
Développement d’un outil pour la modélisation de la contamination de la viande de porc à l’abattoir par Salmonella.
Delhalle, Laurent ; Farnir, Frédéric ; Daube, Georges
Poster (2007, June)Detailed reference viewed: 13 (0 ULg)
Detection of Vibrio cholerae, V. parahaemolyticus and V. vulnificus in seafood using real time PCR.
; ; et al
Poster (2007, June)Detailed reference viewed: 15 (0 ULg)
Exploring the risk factors for Salmonella in the ten biggest Belgian pig slaughterhouses.
Delhalle, Laurent ; ; et al
Poster (2007, May)Detailed reference viewed: 7 (0 ULg)
Description of a new species, Bifidobacterium crudilactis sp. nov., isolated from raw milk and raw milk cheeses.
Delcenserie, Véronique ; ; et al
in Systematic & Applied Microbiology (2007), 30(5), 381-9
A new Bifidobacterium species is described based on the study of ten Gram-positive strains with fructose-6-phosphate phosphoketolase activity. They are part of a phenotypic group comprising 141 strains ... [more ▼]
A new Bifidobacterium species is described based on the study of ten Gram-positive strains with fructose-6-phosphate phosphoketolase activity. They are part of a phenotypic group comprising 141 strains isolated from raw milk and raw milk cheeses in French raw milk cheese factories. This group was separated by a numerical analysis based on API 50CH, API 32A tests and growth at 46 degrees C. A strong similarity of 16S rRNA sequences (99.8%) was shown between strain FR62/b/3(T) and Bifidobacterium psychraerophilum LMG 21775(T). However, low DNA-DNA relatedness was observed between their DNAs (31%). The new isolates are able to grow at low temperatures (all ten strains up to 5 degrees C) and strain FR62/b/3(T) grows under aerobic conditions, as does B. psychraerophilum. However, contrary to B. psychraerophilum, they do not ferment L-arabinose, D-xylose, arbutin or melezitose, but they do acidify lactose. The DNA G+C content of FR62/b/3(T) is 56.4mol%. Therefore, the name Bifidobacterium crudilactis sp. nov. is proposed, with its type strain being FR62/b/3(T) (=LMG 23609(T)=CNCM I-3342(T)). [less ▲]Detailed reference viewed: 70 (21 ULg)
A seven-year survey of Campylobacter contamination in meat at different production stages in Belgium
; ; et al
in International Journal of Food Microbiology (2007), 116(1), 35-45
The presence of Campylobacter was assessed in different samples of poultry, pork and beef meat and carcasses from slaughterhouses, production plants and retail level. An introductory study from 1997 to ... [more ▼]
The presence of Campylobacter was assessed in different samples of poultry, pork and beef meat and carcasses from slaughterhouses, production plants and retail level. An introductory study from 1997 to 1999, had the purpose of establishing the optimum dilution to detect changes in prevalence and allowed a semi-quantitative estimation of poultry and pork contamination. Following this, between 2000 and 2003, 4254 samples were taken in order to study the trends. The poultry matrixes represented the greatest number and the most highly contaminated samples, with 30.9% (in 0.01 g) positive samples, 18.7% (in 1 g), 46.9% (in 25 g) and 19.6% (in 0.01 g) for broiler carcasses, broiler fillets, prepared chicken and layer carcasses, respectively. Broiler carcasses and fillets sampled at retail level were significantly less contaminated than samples from production plants. Pork, beef and veal samples were rarely contaminated and, where contamination existed, it was at a low prevalence (maximum 5.0%). The high and unvarying prevalence of Campylobacter in poultry necessitates the implementation of intervention measures at the primary production level, in addition to methods of minimizing cross-contamination at the processing level. A survey plan in line with the present study could be used in the future to monitor the effects of the planned measures and performance objectives and to follow the evolution of Campylobacter contamination at all stages of the food chain, in accordance with European legislation. (c) 2007 Elsevier B.V. All rights reserved. [less ▲]Detailed reference viewed: 77 (3 ULg)
Le point sur les méthodes de surveillance de la contamination microbienne des denrées alimentaires d’origine animale.
; Daube, Georges
in Annales de Médecine Vétérinaire (2007), 151
Foodborne disease have an important impact on the public health. In Europe and in the USA, Salmonella and Campylobacter are the two main bacterial causes because of their presence in the intestinal tract ... [more ▼]
Foodborne disease have an important impact on the public health. In Europe and in the USA, Salmonella and Campylobacter are the two main bacterial causes because of their presence in the intestinal tract of poultry, pig and beef. For the monitoring of the bacterial contamination of food, the enumeration of certain groups or species of bacteria of intestinal origin is an alternative to the detection of the pathogenic microorganisms. They can be used as index indicating the possible presence of pathogenic agents having a similar ecology, or as indicators announcing the non-observance of the good practices. The most used are the total plate counts, E. coli and the Enterobacteriaceae. During meat production, they are counted at the level of environment, along the food chain, on carcasses at the slaughterhouse, on carcasses and in meat, in plants and distribution. Various surveys are carried out by the producers of food and the authorities for the control of the auto-control, the national inspection plans or to determine the national baseline. [less ▲]Detailed reference viewed: 359 (13 ULg)
Les Escherichia coli producteurs de shigatoxines dans les toxi-infections d'origine alimentaire.
; ; Daube, Georges
in Annales de Médecine Vétérinaire (2007), 151
Certains Escherichia coli producteurs de Shigatoxines (STEC) sont responsables de toxi-infections d’origine alimentaire qui se traduisent par des diarrhées mais aussi par des syndromes plus graves pour ... [more ▼]
Certains Escherichia coli producteurs de Shigatoxines (STEC) sont responsables de toxi-infections d’origine alimentaire qui se traduisent par des diarrhées mais aussi par des syndromes plus graves pour l’homme comme le syndrome hémolytique urémique pouvant provoquer la mort. Il s’agit d’agents zoonotiques dont le réservoir principal est le bovin et les autres ruminants. Les principaux modes de transmission des infections à STEC à l’homme sont la consommation d’aliments contaminés (viande de boeuf peu cuite, produits laitiers non pasteurisés), la transmission de personne à personne, l’ingestion d’eau contaminée et le contact avec des animaux (notamment les bovins) et leur environnement. Les facteurs de virulence des Escherichia coli producteurs de Shigatoxines sont principalement les protéines codées par un îlot de pathogénicité, « Locus of Enterocyte Effacement », impliquées dans la formation de la lésion d’attachement et d’effacement et de la diarrhée et les toxines de Shiga codées par des bactériophages et impliquées dans les syndromes extraintestinaux. La souche de STEC du sérotype O157:H7 est responsable d’épidémies dans le monde causant des milliers de malades et des dizaines de morts. De nombreuses méthodes de diagnostic ont été développées pour identifier ce pathogène à partir des aliments. Elles regroupent des méthodes de bactériologie classique, des méthodes immunologiques et des méthodes moléculaires. Des mesures d’hygiène sont particulièrement importantes pour éviter la contamination des animaux à la ferme et celle de la viande à l’abattoir. Enfin, des modèles d’évaluation du risque ont été développés notamment afin de modéliser le comportement des STEC dans l’aliment. [less ▲]Detailed reference viewed: 141 (8 ULg)