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1.
The effect of introducing vaccinated commercial laying chickens on to farms, which previously had laying flocks that were infected with Salmonella Enteritidis, was investigated by sampling faeces and environmental samples, and in some cases spent hens. In 15 of 17 free-range flocks vaccination eliminated any evidence of infection. In 11 barn egg production flocks, vaccination produced similar results in four flocks on one farm but infection persisted in seven flocks on other farms. Vaccination of two consecutive cage layer flocks led to a gradual disappearance of the infection, but in 18 other flocks there was evidence of infection after vaccination. In one continuously occupied cage layer house, treatment by competitive exclusion was followed by a gradual disappearance of S Enteritidis in faeces and a substantial reduction in its levels in the environment. On four barn egg production sites disinfection with a formaldehyde, glutaraldehyde and quaternary ammonium compound disinfectant eliminated Salmonella species even though birds housed subsequently were not vaccinated. In three flocks that had been vaccinated for four years, S Enteritidis was still present. In most cases the poor performance of the vaccine was associated with severe rodent control problems and a poor standard of cleaning and disinfection. 相似文献
2.
Faecal, dust and other environmental samples were collected from the floors, droppings belts, egg-collection systems and other areas of 14 cage-layer flocks, 10 barn egg production flocks and seven free-range flocks, and cultured for Salmonella species. The distribution of the organism varied with its prevalence and with the vaccination status of the birds. No one sample type was found to be suitable for identifying all contaminated houses. Salmonella was also frequently found on egg-packing equipment and in samples from rodents and wild birds. 相似文献
3.
Salmonella infection of laying flocks in the UK is predominantly a problem of the persistent contamination of layer houses and associated wildlife vectors by Salmonella Enteritidis. Methods for its control and elimination include effective cleaning and disinfection of layer houses between flocks, and it is important to be able to measure the success of such decontamination. A method for the environmental detection and semi-quantitative enumeration of salmonellae was used and compared with a standard qualitative method, in 12 Salmonella-contaminated caged layer houses before and after cleaning and disinfection. The quantitative technique proved to have comparable sensitivity to the standard method, and additionally provided insights into the numerical Salmonella challenge that replacement flocks would encounter. Elimination of S. Enteritidis was not achieved in any of the premises examined although substantial reductions in the prevalence and numbers of salmonellae were demonstrated, whilst in others an increase in contamination was observed after cleaning and disinfection. Particular problems with feeders and wildlife vectors were highlighted. The use of a quantitative method assisted the identification of problem areas, such as those with a high initial bacterial load or those experiencing only a modest reduction in bacterial count following decontamination. 相似文献
4.
The effectiveness of cleaning and disinfecting broiler farms and the persistence of Salmonella species in two integrated broiler companies was investigated for two years. Both companies used a cleaning and disinfection regime which included the application of a spray of phenolic disinfectant followed by fogging with formaldehyde solution, and this was highly effective in preventing carry-over of infection in the broiler houses. The disinfection of service areas and areas outside the houses was less effective but it had no influence on the Salmonella status of later flocks. Both companies had persistent problems with the contamination of pellet cooling systems in their feedmills with Salmonella 4, 12:d:- in company A, and with Salmonella binza and Salmonella ohio in company B. The hatcher incubators of both companies were also persistently contaminated with Salmonella livingstone and Salmonella thomasville in company A and with Salmonella senftenberg in company B. At both companies sites Salmonella enteritidis and Salmonella typhimurium Tr104 were also isolated occasionally from various locations. 相似文献
5.
A. Huneau-Salaün V. Michel L. Balaine I. Petetin F. Eono F. Ecobichon 《British poultry science》2010,51(2):204-212
1.?The aim in this study was to evaluate cleaning and disinfection programmes in battery cage and on-floor layer houses in France.
2.?Cleaning and disinfection efficiency was assessed by a visual evaluation of cleaning and a bacteriological monitoring of surface contamination from counts of thermotolerant streptococci on contact agar plates.
3.?In battery cage houses, dropping belts, manure conveyors, and house floors remained highly contaminated due to poor cleaning in half of the buildings examined.
4.?In on-floor houses, a high standard of cleaning was achieved but errors in the planning of cleaning and disinfection operations sometimes led to a high residual contamination of nest boxes and egg sorting tables. 相似文献
6.
Skov MN Spencer AG Hald B Petersen L Nauerby B Carstensen B Madsen M 《Avian diseases》2004,48(1):9-18
We evaluated the role of beetles infesting broiler chicken rearing facilities as potential reservoirs for Salmonella enterica infections between successive broiler flocks. In addition, their role as potential reservoirs for thermophilic Campylobacter spp. was also investigated. Fourteen broiler houses located at 11 different farms were included in the study. The houses were nonrandomly selected on the basis of their salmonella status; nine were persistently contaminated with salmonella whereas five were salmonella negative. For each broiler house, two consecutive broiler flocks (i.e., 28 broiler flocks in all) as well as beetles collected during both rotations of production and in the empty period (after cleaning and disinfection) between these flocks were monitored for the presence of salmonella. Examinations for the presence of campylobacter in the same sample materials were also performed. Beetles sampled during production were positive for salmonella or campylobacter or both. Furthermore, in one house, the occurrence of Salmonella indiana in two consecutive broiler flocks coincided with the presence of S. indiana-contaminated beetles in the empty period between the flocks. The genotype of the identified S. indiana was in all cases identical when analyzed by pulsed-field gel electrophoresis. However, our results also suggest that salmonella from beetles may not always be transmitted to the chickens and that beetles living in contaminated houses can remain free of infection. All cases of campylobacter-positive beetle samples were detected in connection with a positive chicken flock; in no case was campylobacter isolated from beetles taken from the empty period between rotations. Four beetle species were identified during this study. Alphitobius diaperinus was found in all houses and was relatively abundant in most. Typhaea stercorea and Ahasverus advena were found in eight and nine houses, respectively, and were abundant in most of these. Carcinops pumilio was found in small numbers in eight houses. No other insect species was identified. These investigations have shown that beetles in broiler houses infrequently are positive for salmonella. However, transmission of S. indiana between two consecutive broiler flocks can coincide with the presence of salmonella-contaminated beetles in the empty period, indicating that the beetles were the reservoir of S. indiana between the two flocks. Concerning campylobacter, the results suggest that beetles do not play a significant role as a reservoir of campylobacter from one rotation to the next. 相似文献
7.
Le Bouquin S Allain V Rouxel S Petetin I Picherot M Michel V Chemaly M 《Preventive veterinary medicine》2010,97(3-4):245-251
A nation-wide survey was carried out in 370 randomly chosen French commercial broiler chicken flocks from October 2005 to September 2006 to determine Salmonella spp. prevalence and to identify risk factors for contamination, at the end of the rearing period. The Salmonella status of the flocks was assessed from five faecal samples (litter swabs) analysed by classical bacteriological methods. A flock with at least one contaminated sample was classified as a Salmonella-positive flock. The apparent prevalence of Salmonella was 8.6% (95% CI: 5.7, 11.5%). The most prevalent serovar was S. hadar followed by S. anatum and S. mbandaka. Logistic regression methods were used to analyse the associations between husbandry practices, farm characteristics, general hygiene and the Salmonella status of the sample. The risk for Salmonella contamination of the flock at the end of the rearing period increased when neighbours helped in the placement of day-old chicks. On the contrary, the risk decreased when mobile equipment was dismantled before cleaning and disinfection, when the farm had a specific container for dead-bird disposal and when acetic acid was added to the drinking water. 相似文献
8.
Singer RS Jeffrey JS Carpenter TE Cooke CL Atwill ER Johnson WO Hirsh DC 《Veterinary microbiology》2000,75(1):59-71
Avian cellulitis in broiler chickens is primarily caused by Escherichia coli. Previous research found that the E. coli isolates of cellulitis origin were unique to each ranch, suggesting that these E. coli were endemic within the ranch environment. To test the hypothesis that the E. coli associated with cellulitis are endemic in the litter of the broiler house, we designed a study to determine whether E. coli DNA fingerprints associated with cellulitis persist over successive flocks that are grown in the same house. In addition, we assessed the impact of different cleaning and disinfection strategies on this persistence. Two broiler houses were followed on each of five farms over 3-4 flocks. A total of 353 E. coli isolates from cellulitis lesions were analyzed in this study, and 314 of these isolates (89%) were DNA fingerprinted by PFGE. In each ranch, there were several DNA fingerprint patterns that were present over successive flocks, regardless of the cleaning and disinfection strategy utilized. Isolates persisted as long as 191 days, implying that these E. coli are capable of persisting in the broiler house environment for long periods of time. In addition, these E. coli isolates were associated with cellulitis lesions in successive flocks. Thus, the isolates of E. coli that are associated with cellulitis in broiler chickens appear to be endemic in the litter environment of the broiler house. 相似文献
9.
Engström BE 《Acta veterinaria Scandinavica》1999,40(2):97-107
A serological survey for antibody to Chicken Anaemia Virus (CAV) was performed on broiler breeders as well as layer breeding birds in Sweden at the end of their rearing period. Grandparents (GP) of both types leaving quarantine were in 21 out of 26 cases free from antibody to CAV, but often became infected soon thereafter. A total of 10 outbreaks of blue wing disease (BWD) in 3 series were recorded in the broiler and layer parent generation, all of which were progeny of 3 late seroconverting GP-flocks. All but one of 22 layer parent flocks had been infected and had seroconverted during the rearing period. Subsequently BWD was not recorded from commercial layers. Broiler parent flocks were more protected from CAV infection during rearing. Eighteen out of 94 broiler parent flocks had not developed antibody to CAV before coming into lay. Outbreaks of BWD were reported in progeny flocks from all these broiler breeders, with the exception of those that had been vaccinated. Good hygienic routines along with isolation of the birds delayed the seroconversion to CAV in broiler breeders and vaccination of these breeders protected their progeny from outbreaks of BWD. Broiler flocks in houses where BWD had occurred recently had always antibodies to CAV at slaughter. It was possible to eradicate the infection from the house and prevent the infection between flocks by proper cleaning and disinfection of the broiler houses. 相似文献
10.
《The Journal of Applied Poultry Research》2014,23(1):59-70
The shell of the egg is essential in providing shape to the egg and ensuring safe packaging of the internal contents; however, shell defects have been shown to increase the risk of microbial contamination of eggs. Eggs were collected from commercial cage and free-range flocks at the ages of 25, 35, 45, 55, 65, and 75 wk. From each collection per flock, 30 eggs were processed for the eggshell and egg internal quality determination, 30 eggs for cuticle estimation, 30 eggs for mammillary layer ultrastructural features scoring, and 60 eggs for egg microbial enumeration. Translucency score and shell reflectivity were significantly higher in free-range eggs and increased with flock age in both production systems. Egg weight, shell weight, percentage shell, shell thickness, albumen height, Haugh unit, and yolk color were higher for cage eggs. The amount of cuticle was higher in cage eggs and fluctuated with flock age in both production systems. For the mammillary layer ultrastructural variables, a significant effect of production system and flock age was observed for early fusion, Type A bodies, and Type B bodies, whereas aragonite, depression, erosion, and hole were rarely observed. Variability of mammillary cap size, the incidence of poor mammillary cap quality, incidence of late fusion, alignment, Type A bodies, Type B bodies, and cubic cone formation were greater in the free-range versus cage system and increased with flock age in both production systems. The incidence of confluence and early fusion were greater in cage eggs and decreased with age in both production systems. Significantly lower total microbial load was observed for cage compared with free-range eggs, but the overall bacterial load recorded in this study was low. It can be concluded that cage eggs were better in overall quality when directly compared with free-range eggs. 相似文献
11.
1. The welfare of hens in 26 flocks (6 conventional cage, 6 furnished cage, 7 barn, 7 free-range) was assessed throughout the laying period using a combination of data on physical health, physiology and injurious pecking, collected by researchers on farm and during post-mortem analysis, and information submitted by producers. 2. There was an effect of housing system on 5 of the indicators recorded by researchers: gentle feather pecks given, feather damage score, proportion of hens with feather damage, proportion of the flock using perches, and faecal corticosterone. 3. Post-mortem analysis revealed several differences between housing systems in skin damage, plumage damage to the vent and abdomen, keel protrusion, bodyweight, and the proportion of hens that were vent pecked and that had old and recent keel fractures. 4. There was an effect of housing system on 5 indicators recorded by producers: proportion of egg shells with calcification spots, proportion of egg shells with blood stains, weight of hens found dead, temporal change in the proportion of egg shells with stains, and temporal change in proportion of hens found dead. 5. Each housing system had positive and negative aspects but overall, hens in barn systems had the highest prevalence of poor plumage condition, old fractures, emaciation, abnormal egg calcification, and the highest corticosterone. Hens in conventional cages sustained more fractures at depopulation than birds in other systems. Vent pecking was most prevalent in free-range flocks. The lowest prevalence of problems occurred in hens in furnished cages. 6. Although housing system had an influence on the hens' physical condition and physiological state, the high prevalence of emaciation, loss of plumage, fractures and evidence of stress is of concern across all housing systems, and suggests that the welfare of modern genotypes is poor. 相似文献
12.
Rose N Mariani JP Drouin P Toux JY Rose V Colin P 《Preventive veterinary medicine》2003,59(1-2):27-42
We built a decision-support system to assess the risk of contamination of chicken-broiler flocks by Salmonella at the end of the rearing period. This system was developed from the survey data from 85 chicken-broiler flocks located in western France. First, we estimated the probability of contamination of the house by Salmonella before placement of day-old chicks via a cleansing inspection using a visual-inspection grid, a decontamination evaluation using count-plates, and risk factors for Salmonella persistence in the barn after cleansing and disinfection. Second, we estimated (using a logistic model) the probability of prevalent contamination of the flock by Salmonella at the end of the rearing period. Validation was carried out on 60 flocks selected from seven production companies in western France. The risk estimated by the model was compared to the Salmonella status of the flock (gold standard) assessed by samples taken from the environment of the broilers and analysed with classical bacteriological methods. The sensitivity was 97.8% and the specificity 64.3%. 相似文献
13.
One hundred flocks associated with five integrated poultry companies were monitored for one production cycle to investigate risk factors for campylobacter infection of poultry broiler flocks. Bacteriological samples were collected from one house of birds on each site at weekly intervals from 3 to 4 weeks of age until the birds were infected with campylobacter or the flock was depopulated (whichever was sooner). Environmental samples were obtained from 20 houses after cleansing and disinfection of the site before chick arrival. Conventional methods were used for the isolation of campylobacter. Questionnaires were used to collect information on potential risk factors for campylobacter infection. Discrete-time survival analysis was used to assess the influence of various exposures on the age at which the flock was infected with campylobacter.More than 40% of flocks were infected with campylobacter by the time the chicks were 4 weeks old and >90% by 7 weeks. Infection spread rapidly to most birds in a flock. Infection was not predictable by campylobacter status of the last flock reared on the site. (However, because most flocks were infected, the power to detect such an association was poor.) There was no evidence of environmental survival of campylobacters in broiler houses after adequate cleansing and disinfection. The most important predictors of protection from campylobacter were related to effective hygiene barriers (such as housing birds in buildings in a good state of repair, appropriate usage of disinfectant boot dips and a high standard of cleansing and disinfection of the drinking-water equipment). There was no evidence that rodents were a source of infection (but most sites operated effective vermin-control programmes). 相似文献
14.
Evaluation of Salmonella serotype distributions from commercial broiler hatcheries and grower houses
By conventional trayliner (hatcheries) and drag swab assembly (broiler houses) culture methods, the isolation distribution of Salmonella serotypes from five commercial broiler hatcheries (three sample times) and 13 broiler farms (eight sample times) was evaluated. A total of 11 different Salmonella serotypes were isolated from hatcheries, with Salmonella heidelberg (9/30) and Salmonella kentucky (6/30) accounting for 50% of the total isolations. Of 700 chick paperpad trayliners sampled, regardless of lot (breeder flock source) or hatchery, 12% were positive for Salmonella. When 10 individual trayliners were cultured from individual lots (same breeder flock source), Salmonella was detected in 24/57 lots (42%). Multiple serotypes were simultaneously isolated from the same lot on three occasions (6%). Of the 21 lots that were serially sampled, the Salmonella serotype detected was different within lots eight times (38%) on at least one occasion of two or more sampling times. Of the 196 individual broiler houses sampled, 44 were positive for Salmonella (42%). Twelve different serotypes were isolated from broiler houses during this study. The serotypes isolated most frequently were S. heidelberg (34/94) and S. kentucky (22/94). These two serotypes accounted for 59.6% (56/94) of the total broiler house isolations. Of the 38 houses that were serially sampled, two or more serotypes were detected in the same broiler house on 20 occasions (53%). Of the 38 serially sampled houses (four or more times), a consistent Salmonella serotype was detected in five houses (13%). In only 5 of the 38 (13%) serially sampled houses did we fail to detect Salmonella on four or more samplings. No significant difference in Salmonella isolation frequency was observed between poultry houses using new or used litter. These data support previous findings indicating that paratyphoid Salmonella serotypes are prevalent in some broiler hatcheries and houses. Further, the observation of multiple serotypes simultaneously and serially isolated from the same breeder hatchery lots suggests that breeder flocks may be infected with more than one serotype, possibly providing a source for multiple serotype infections in progeny grower flocks. 相似文献
15.
Prevention of Salmonella contamination of poultry products requires detailed knowledge of the main sources associated with its presence in the production system. The aims of this study were to determine the main sources of Salmonella contamination in broiler production during growing, to assess the risk factors for Salmonella contamination at the end of the rearing period and to determine the main serovars involved in broiler production systems in Eastern Spain. A total of 65 different broiler houses from different farms were sampled. Each house was sampled at different times during the rearing period. First, when the previous flock was taken to the slaughterhouse, samples of dust, surfaces and previous flock faeces were collected. After cleaning and disinfection (C&D), samples of dust and surfaces were also taken. On the first day of rearing, samples of water, bedding, farming boots, meconiums, delivery-box liners and feed were collected. During rearing, feed samples were taken directly from the truck and from feeders. On slaughter day, samples of dust, surfaces, water, feed and faeces were also collected. Finally, two days after slaughter, carriers (rodents, flies and beetles) were trapped. All samples collected were analysed according to ISO 6579:2002 (Annex D) and positive samples were serotyped in accordance with Kauffman-White-Le-Minor technique. Our results showed that all different types of samples collected were contaminated with Salmonella (prevalence ranged between 1.5% and 38.6%). The most contaminated samples related with poultry production were: delivery-box liners (32.0%), faeces samples (31.2%), dust samples (25.0%), farming boots (19.7%) and feed from feeders (16.0%). However, the most important risk factors for Salmonella contamination of the flocks at the end of the rearing period were Salmonella status of the house after cleaning and disinfection, Salmonella status of day-old chick flocks and feed from feeders. Twenty-one different serovars were isolated from the samples analysed. The most prevalent were in decreasing order: Salmonella Enteritidis (52.9%), S. Hadar (17.8%), S. Virchow (8.9%) and S. Ohio (5.4%). The study suggested that there are many sources for Salmonella contamination and persistence in broiler production. Hence, the whole production chain needs to be controlled to eradicate the bacteria from primary production. 相似文献
16.
Namata H Méroc E Aerts M Faes C Abrahantes JC Imberechts H Mintiens K 《Preventive veterinary medicine》2008,83(3-4):323-336
Since the 1980s, the prevalence of Salmonella in Belgian poultry layers and broilers has greatly fluctuated with a rise observed in 2003 and a significant decrease in 2005. In order to alleviate the risk at egg consumer level, it is crucial to understand the factors which influence the contamination and the spread of Salmonella in laying hens. To study such determinants we explored the Belgian data from the 2005 baseline study on the prevalence of Salmonella in laying flocks of Gallus gallus in the European Union. The response variables corresponded to presence or absence of Salmonella from dust and faecal samples taken from the environment of a Belgian layer flock. The explanatory variables included: region of Belgium, sampling time (month the flock was sampled), production type (cage or barn and free range), Salmonella vaccination status, flock age and flock size. Analyses of these data were performed using a bivariate logistic regression model assuming independence between the two responses and bivariate generalized estimating equations model, which incorporates the correlation between the two responses on the same flock. The main risk factor that was identified was rearing flocks in cages compared to barns and free-range systems. The results also showed a significant higher risk for Salmonella for a 1 week increase in flocks’ age as well as with a unit increase in the size of the flock. 相似文献
17.
Old breaks of the keel and furculum were identified by palpation in 500 end-of-lay hens from 10 flocks housed in free-range and barn systems, and the results were compared with the results obtained by a full dissection and inspection. The method was considered to be sufficiently precise to be used as a diagnostic tool although people using it would need to be trained. The results obtained by dissection indicated that 50 to 78 per cent of the birds in the flocks had breaks of the furculum and keel, but no other breaks of bones were detected. 相似文献
18.
Mahé A Bougeard S Huneau-Salaün A Le Bouquin S Petetin I Rouxel S Lalande F Beloeil PA Rose N 《Preventive veterinary medicine》2008,84(1-2):11-26
A study was carried out to estimate the prevalence of flocks infected by Salmonella spp., S. Enteritidis and S. Typhimurium in 521 French laying-hen farms from October 1st 2004 to September 30th 2005 as part of a European Union-wide baseline study to define targets for Salmonella reduction in member states. The sampling scheme prescribed and financed by the European Commission to detect Salmonella in laying-hen flocks was based on 2 dust-samples and 5 faeces-samples per farm. A latent-class Bayesian approach for correlated tests was used to estimate the sensitivity of detection of reduced sampling schemes corresponding to the 16 combinations of 2 dust- and 5 faeces-samples. For each model the full sampling scheme (7 samples) and the reduced protocol were considered as two correlated tests, the biological principle being identical and the reduced protocol being a subset of the full sampling scheme. As the observed apparent prevalence in cage flocks was higher than in other systems (barns, outdoor, or organic) these two sub-populations were considered separately. Bayesian estimation of posterior medians with 95% probability intervals for true prevalence in cage flocks were 0.34 (0.29; 0.39) and 0.13 (0.10; 0.18) for Salmonella spp. and Salmonella Enteritidis+Typhimurium respectively. In alternative flocks posterior medians with 95% probability intervals for true prevalence were 0.09 (0.06; 0.13) and 0.05 (0.03; 0.08) for Salmonella spp. and Salmonella Enteritidis+Typhimurium, respectively. In cage flocks Bayesian estimation of posterior distributions for sensitivity indicated that at least 5 samples, including 2 dust samples were necessary to attain comparable sensitivity levels to the full sampling scheme. In alternative flocks and for Salmonella spp. 6 samples were required to ensure a comparable sensitivity level to the full sampling scheme. Detection sensitivity was improved by increasing the number of dust samples in cage farms and by increasing the total number of samples whatever their type in alternative farms. 相似文献
19.
Pullorum disease causing acute septicemia and mortality in adult brown chickens was diagnosed in a small-farm chicken flock in Iowa. Also, Salmonella Pullorum was isolated from the intestine of one of four rats trapped on this index farm. Tracing movements of spent hens from the index farm resulted in identification of a second infected flock on a contact farm. Poultry on the contact farm were tested with the stained-antigen, rapid whole-blood test, and two ducks and one chicken gave positive reactions. Reactors were necropsied and cultures of appropriate tissues resulted in isolation of Salmonella Pullorum from one duck and the chicken. Pulsed-field gel electrophoresis banding patterns of Salmonella Pullorum isolates from chickens on the index and contact farms, the duck, and the rat demonstrated that all isolates were genetically very similar. Both flocks were quarantined and depopulated and a detailed flock cleanup plan was created for both farms. After extensive cleaning and disinfection procedures were completed on the index farm, environmental monitoring and bioassays of trapped mice were conducted. Negative cultures of environmental swabs and trapped mice and negative blood tests of all birds conducted 4 mo after placement of a new flock on the index farm demonstrated that cleaning and disinfection methods used in this outbreak had successfully eliminated Salmonella Pullorum organisms from this farm. 相似文献
20.
《The Journal of Applied Poultry Research》2006,15(2):326-332
Little is known about the effectiveness of current poultry industry cleaning and disinfection procedures in broiler barns. Surface swabs were taken from a commercial broiler barn and a research broiler barn. The swabs were analyzed to determine if cleaning and disinfectant processes used would reduce the numbers of total aerobic bacteria and the total Enterobacteriaceae on the walls of the commercial barn (Experiment 1) and on the walls and floor of the research barn (Experiment 2). Microbiological analyses were used to assess bacterial loads within each barn. In Experiment 1 the mean of total aerobic bacterial counts were not affected by the cleaning and disinfectant process. However, the means of total Enterobacteriaceae counts were significantly reduced by the washing process. Disinfection with Virkon did not further reduce the numbers of Enterobacteriaceae. In general, the cleaning processes used in wood and metal barns were effective in reducing Enterobacteriaceae counts. In Experiment 2, neither the mean of total aerobic bacterial counts nor Enterobacteriaceae counts were affected by the washing process. However, disinfection with Virkon did result in a significant reduction of bacterial numbers. In summary, the disinfectant step performed in the research barn was effective in decreasing both total aerobic and Enterobacteriaceae counts. 相似文献