Prevalence of Arcobacter spp. in raw ground pork from several geographical regions according to various isolation methods

Studies show that the pathogen Arcobacter is present in beef, poultry, and pork. Several methods have been reported for the isolation of this organism, but none has been adopted as the standard. This has limited the significance of field comparison studies. In the present study, we compared the efficiencies of four Arcobacter isolation methods using raw ground pork collected from slaughter facilities across the United States. We also evaluated the effect of meat fat level and age of animals on the prevalence of Arcobacter in ground pork. The methods chosen for comparison of isolation efficiency were those of Collins, a modified version of the Collins method (Direct Collins), deBoer, and Johnson Murano (JM). These were chosen based on published reports in which they were used to detect Arcobacter in pork products. The JM method was found to be the most successful in consistently detecting Arcobacter, isolating it in 64 of 200 pork samples compared with the Direct Collins method, which isolated Arcobacter in 52 of 200 of those same samples. The Collins method and the deBoer method found Arcobacter present in only a fraction of the samples. The level of contamination was found to vary among the plants, ranging from 0% to 68% prevalence, with 32% overall for all four plants tested. Additionally, ground pork low in fat had a higher contamination frequency (20%) when compared with high-fat pork (4%). Results also showed that meat from younger animals was more frequently contaminated than that from older animals.     

Molecular characterization of Arcobacter isolates collected in a poultry slaughterhouse

In a poultry slaughterhouse, Arcobacter contamination was examined over a period of 1 week to establish possible routes of contamination. Samples were collected from the slaughter equipment and from processing water before the onset of slaughter and from the first broiler flock slaughtered on each sampling day. Characterization of 1,079 isolates by enterobacterial repetitive intergenic consensus-polymerase chain reaction and a random amplified polymorphic DNA assay resulted in the delineation of 159 Arcobacter butzleri and 139 Arcobacter cryaerophilus types. From almost all 140 neck skin samples collected before and after evisceration, A. butzleri and A. cryaerophilus were isolated simultaneously at contamination levels ranging from 10(1) to 10(4) CFU/g. Only six A. butzleri types present in the slaughterhouse environment were also present on the broiler carcasses. None of the A. cryaerophilus genotypes were detected in both the neck skin and the environmental samples. All A. butzleri types isolated from the feather samples were also isolated from broiler neck skin samples. The slaughter equipment was contaminated with arcobacters before the onset of slaughter, but it appeared unlikely that contamination through the slaughter equipment alone explained the high contamination levels on poultry products. Arcobacters were also present in processing water, but types present in water and poultry products were different. Characterization of the Arcobacter isolates did not clarify the routes of transmission, probably because of the extreme heterogeneity among Arcobacter isolates. However, the results obtained in this study brought to light insufficient decontamination at the processing plant involved in the study and confirmed the survival capacity of certain A. butzleri strains.     

Direct detection and identification of Arcobacter species by multiplex PCR in chicken and wastewater samples from Spain

Twenty-two chicken livers, 10 chicken carcasses, and 15 wastewater samples were processed and analyzed for Arcobacter by PCR and traditional culture methods. Samples were enriched for 24 and 48 h, incubated at 30 degrees C under aerobic conditions, and streaked on blood selective media. To determine the best isolation conditions, 20 samples also were processed under microaerophilic conditions at 37 degrees C. Simple and multiplex PCR assays were used directly with enrichment broths and isolated strains. Seventeen Arcobacter strains were isolated from chicken samples, and A. butzleri was the only Arcobacter species identified. The direct PCR assay revealed that 29 of the 32 chicken samples were contaminated with Arcobacter. A. butzleri was the most frequently detected species, although Arcobacter cryaerophilus also was present in some of the samples and Arcobacter skirrowii occasionally was detected. All the wastewater samples were positive by PCR assay for Arcobacter after 24 h of enrichment. A. butzleri and A. cryaerophilus were detected with the multiplex PCR assay. Fourteen Arcobacter strains were isolated from 10 of the 15 water samples analyzed; 7 were identified as A. butzleri and the remaining 7 were A. cryaerophilus. Both for chicken and water samples, Arcobacter detection rate for PCR amplification was higher than for culture isolation. These results indicate the high prevalence of Arcobacter in chicken and wastewater and the inadequacy of available cultural methods for its detection. The species-specific multiplex PCR assay is a rapid method for assessing Arcobacter contamination in chicken and wastewater samples and is a viable alternative to biochemical identification of isolated strains.     

Determination of the occurrence of Arcobacter butzleri in beef and dairy cattle from Texas by various isolation methods

Arcobacter butzleri is a pathogenic bacterium that has been found in dairy cattle, pigs, poultry, and humans. As of this writing, there are no data on the incidence of A. butzleri in beef cattle. Given the differences in rearing practices used for feedlot cattle and those used for dairy cattle, differences in the incidences of this organism in various types of cattle may also exist. Numerous culture methods have been used to isolate A. butzleri, but there are few data on the comparative efficacies of these methods. The objectives of this study were to determine the incidence of A. butzleri in cattle from Texas and to compare the effectiveness levels of the Johnson-Murano (JM) method (consisting of enrichment in JM broth followed by plating on JM agar) and the Collins method (consisting of enrichment in EMJH-P80 broth followed by plating on Cephalothin, Vancomycin, and Amphotericin B [CVA] agar) in the isolation of this organism. Fifty cattle each from two feedlots, a dairy, and a stocker yard were sampled. Fecal swabs were obtained from cattle, and each sample was cultured by the JM method, the Collins method, and combinations of the two methods with the broth of one method being used with the agar of the other. Polymerase chain reaction was used to identify the isolates for confirmation of A. butzleri. Samples from 18 of 200 cattle tested positive for A. butzleri. This organism was detected by the JM method in 4.5% of the samples and by the Collins method in 2.5% of the samples. An incidence of 4.0% was found when JM broth was used with CVA agar, while no samples tested positive for A. butzleri when EMJH-P80 broth was used with JM agar.     

石家庄市零售鸡肉样品中弓形杆菌污染调查

目的调查石家庄市零售鸡肉中弓形杆菌的污染情况,为石家庄市弓形杆菌分布特征和防控提供基础数据支持。方法从石家庄市市内四区的菜市场、超市、连锁肉店随机购买零售鸡肉样品90份,应用驱动增强动力双孔滤膜法从样品中分离培养弓形杆菌,利用弓形杆菌多重聚合酶链式反应(PCR)检测及测序的方法对分离菌株进行种属鉴定,利用16S rDNA、rpoB基因测序的方法验证菌种鉴定结果。结果 90份鸡肉样品中,60份样品检出弓形杆菌86株,其中嗜低温弓形杆菌49株、布氏弓形杆菌37株,弓形杆菌检出率为66.67%(60/90)。60份阳性样品中,嗜低温弓形杆菌阳性样品45份(75.00%),布氏弓形杆菌阳性样品35份(58.33%)。嗜低温弓形杆菌和布氏弓形杆菌混合感染阳性样品20份,占比为22.22%(20/90)。不同采样点弓形杆菌检出率有较大差异。结论石家庄市零售鸡肉中弓形杆菌污染较重,嗜低温弓形杆菌污染率高于布氏弓形杆菌,两种弓形杆菌混合污染样品率较高。     

Development of a new protocol for the isolation and quantification of Arcobacter species from poultry products.

None of the presently available selective supplements for the specific isolation of Arcobacter species allows the growth of Arcobacter butzleri, A. cryaerophilus and A. skirrowii and at the same time fully suppresses the accompanying flora present in poultry and poultry products. Furthermore, little is known about the contamination levels of poultry with Arcobacter species. In this study, a new selective supplement comprising amphotericin B (10 mg/l), cefoperazone (16 mg/l), 5-fluorouracil (100 mg/l), novobiocin (32 mg/l) and trimethoprim (64 mg/l) was developed. With a new isolation procedure, including enrichment in Arcobacter broth with the selective supplement, incubated for 24 to 48 h at 28 degrees C under microaerobic conditions, arcobacters were isolated from 100% (n = 34) of neck skin of laying hens and from 90% (n = 71) of similar samples from broilers. Of the broiler breast meat samples examined (n = 52), 65% were found to be contaminated with these bacteria. In 64% of the samples, A. butzleri was the only Arcobacter species isolated. In 9% of the samples, A. cryaerophilus was the only species present, while 11% of the samples were positive for both species simultaneously. Using direct isolation on the selective agar medium developed in this study, incubated for 24 to 48 h under microaerobic conditions at 28 degrees C. 32 out of 45 broiler carcasses and 6 out of 25 broiler breast meat samples carried a bacterial load of arcobacters of 10(2) to 10(3) cfu/g. The prevalence of Arcobacter in Belgian poultry was found higher than the prevalence of thermophilic Campylobacter species in each of the poultry categories examined. The enrichment procedure and the direct plating method were validated for the isolation of A. skirrowii. For this species, growth performance was less than the other two Arcobacter species and it was not isolated nor detected by m-PCR from the naturally contaminated poultry samples examined. This new protocol provides a fast and reliable method for the isolation of Arcobacter species from poultry and can contribute to more comprehensive epidemiological investigations.     

Characterization of the Arcobacter contamination on Belgian pork carcasses and raw retail pork

In the present study, the occurrence of Arcobacter was assessed at four sites on 169 porcine carcasses (foreleg, chest, pelvis and ham) at different stages of slaughter and 47 pork products at retail. Carcass swab samples were enriched in Arcobacter broth containing 5-fluorouracil, amphotericine B, cefoperazone, novobiocine and trimethoprim as selective supplement. After microaerobic incubation, arcobacters were isolated using Arcobacter selective agar plates, containing the selective supplement described above. Some carcass samples and all pork samples were also examined quantitatively. All 862 isolates were identified by a species-specific m-PCR-assay and 182 isolates were further characterized by ERIC-PCR. Arcobacters were isolated from one or more sampling places on 96.4% of the carcasses, with the foreleg and the chest area as the two most contaminated sites. Furthermore, A. cryaerophilus was the most common species. Chilling decreased the number of positive carcasses, but did not eliminate all arcobacters. Direct isolation revealed that only a few carcasses were contaminated with arcobacters on foreleg and/or chest at levels higher than 10(2 )cfu/100 cm(2). Characterization demonstrated a large heterogeneity among the isolates, with ten genotypes present on more then one site per carcass. Fourteen genotypes were simultaneously present on carcasses from different herds slaughtered on the same day, which may indicate cross-contamination. Arcobacters were present in 21% of the pork samples taken at retail, but contamination levels did not exceed 100 cfu per gram. Characterization of the A. butzleri and A. cryaerophilus isolates indicated an additional contamination during processing at retail.     

Detection and diversity of various Arcobacter species in Danish poultry

The prevalence and diversity of different Arcobacter spp. in various poultry species in Denmark were investigated using cultural and multiplex PCR methods. A pool of three fresh droppings obtained at the production site from 70 broiler chicken flocks aged 4-5 weeks was examined. In addition, pools of 10 cloacal swabs taken at the abattoir prior to stunning from each of 15, and 37 duck and turkey flocks, respectively, were analyzed. Thirty fresh broiler chicken carcasses and 29 cloacal swabs from the respective viscera were also examined at the abattoir. Finally, 10 caecal and 10 cloacal swabs from ducks at the abattoir were analyzed individually. In total, 85 Arcobacter isolates were obtained. Of these 45, 20 and 7 were identified as Arcobacter butzleri, Arcobacter cryaerophilus and Arcobacter skirrowii, respectively, using a multiplex PCR. Interestingly, some chicken isolates of A. butzleri showed urease activity, and 6 out of seven A. skirrowi isolates were unable to hydrolyse indoxyl acetate. All chicken carcasses examined were found positive for A. butzleri and/or A. cryaerophilus, whereas 21 (72%) of the 29 chicken cloacal swabs were positive for either A. butzleri (13) or A. cryaerophilus (9). Three (4.3%) out of 70 chicken flocks analyzed were positive only for A. cryaerophilus. Of the ten ducks examined individually, 7 carried A. skirrowii and/or A. cryaerophilus in their cloacae. None of the respective caecal samples were positive. Of the remaining 15 duck flocks, 11 (73%) were positive for A. cryaerophilus (7), A. butzleri (2) or A. skirrowii (2). Four (11%) of the 37 turkey flocks analyzed harboured either A. butzleri or A. cryaerophilus. The carriage rate of Arcobacter was higher in live ducks than those of live broiler chickens and turkeys in the present study. In addition, chicken carcasses slaughtered in Denmark were found to be contaminated with Arcobacter. The presence of Arcobacter spp. both on chicken carcasses and in poultry intestine may be of significance to human health.     

Prevalence and Distribution of Arcobacter spp. in Raw Milk and Retail Raw Beef

A total of 106 beef samples which consisted of local (n = 59) and imported (n = 47) beef and 180 milk samples from cows (n = 86) and goats (n = 94) were collected from Selangor, Malaysia. Overall, 30.2% (32 of 106) of beef samples were found positive for Arcobacter species. Imported beef was significantly more contaminated (46.80%) than local beef (16.9%). Arcobacter butzleri was the species isolated most frequently from imported (81.8%) and local (60%) beef, followed by Arcobacter cryaerophilus in local (33.3%) and imported (18.2%) beef samples. Only one local beef sample (10%) yielded Arcobacter skirrowii. Arcobacter species were detected from cow's milk (5.8%), with A. butzleri as the dominant species (60%), followed by A. cryaerophilus (40%), whereas none of the goat's milk samples were found positive for Arcobacter. This is the first report of the detection of Arcobacter in milk and beef in Malaysia.     

PCR 法检测动物源性食品中布氏弓形菌

弓形菌是一种新型食源性致病菌,其中以布氏弓形菌污染率最高。本研究采用扩增23S rRNA的PCR法特异性检测布氏弓形菌,方法灵敏度可达103 CFU/mL。2株布氏弓形菌均特异性地扩增出了长度为2061 bp的条带;嗜低温弓形菌、斯氏弓形菌、空肠弯曲菌等共18株不同种类的菌株均无扩增产物出现,表明此PCR法能特异性的将布氏弓形菌鉴定到种一级水平。比较实验结果表明,API CAMPY鉴定试剂盒对于布氏弓形菌鉴定仅能到弓形菌属一级水平,本PCR法能实现布氏弓形菌种一级水平的鉴定,用于布氏弓形菌的检测具有优势。55份动物源性食品样品用Johnson-Murano肉汤增菌后用PCR法进行检测,其中5份样品为布氏弓形菌阳性,阳性检出率为9.1%。上述实验结果表明,本方法特异性强、操作简便,节省了检测时间,可用于动物源性食品中布氏弓形菌的快速检测。     

Prevalence and Concentration of Arcobacter spp. on Australian Beef Carcasses

The International Commission on Microbiological Specifications for Foods (ICMSF) classified Arcobacter spp. as emerging pathogens in 2002. Arcobacter spp. have been isolated from numerous food products at retail and from animal carcasses and feces at slaughter. A survey was conducted to determine both the prevalence and concentration of Arcobacter spp. on prechill beef carcasses. Surface swab samples were collected from 130 beef carcasses at the end of processing, prior to chilling. The concentration of Arcobacter spp. was determined by a most-probable-number per square centimeter (3 by 3) method with a limit of detection of 0.12 CFU/cm(2). Of the 100 carcasses examined from export abattoirs, 20 (20.0%) were contaminated with Arcobacter spp., and 5 of these had quantifiable levels of contamination ranging from 0.12 to 0.31 CFU/cm(2). Of the 30 carcasses examined at a pet food abattoir, 25 (83.3%) were contaminated with Arcobacter spp., and 10 of these had quantifiable levels of contamination ranging from 0.12 to 0.95 CFU/cm(2). Three species of Arcobacter, A. butzleri, A. cryaerophilus, and A. skirowii, were identified by PCR. Each of the species was present in an approximately equal ratio from export abattoirs. This study demonstrates that slaughter practices at export abattoirs are sufficient to maintain both low prevalence and low levels of contamination of beef carcasses with Arcobacter spp.     

Effect of pH, NaCl content, and temperature on growth and survival of Arcobacter spp

Growth and survival of six human isolates of the pathogenic Arcobacter spp. in the presence of selected environmental factors were studied. Four strains of Arcobacter butzleri and two strains of Arcobacter cryaerophilus were exposed to pH levels of 3.5 to 8.0. Most strains grew between pH 5.5 and 8.0, with optimal growth of most A. butzleri and A. cryaerophilus strains at pH 6.0 to 7.0 and 7.0 to 7.5, respectively. The 24-h optimal growth range in the presence of NaCl was 0.5 to 1.0% for A. cryaerophilus. However, after 96 h, the optimum was between 0.5 and 2.0% NaCl. The optimum range for growth of A. butzleri strains was 0.09 to 0.5% NaCl after 96 h. The upper growth limits were 3.5 and 3.0% NaCl for A. butzleri and A. cryaerophilus, respectively. Survival at 25 degrees C in up to 5% NaCl was noted for A. butzleri 3556 and 3539 and A. cryaerophilus 3256. Decimal reduction times (D-values) at pH 7.3 in phosphate-buffered saline for three A. butzleri strains were 0.07 to 0.12 min at 60 degrees C, 0.38 to 0.76 min at 55 degrees C, and 5.12 to 5.81 min at 50 degrees C. At pH 5.5, decreased thermotolerance was observed, with D-values of 0.03 to 0.11 min at 60 degrees C, 0.30 to 0.42 min at 55 degrees C, and 1.97 to 4.42 min at 50 degrees C. Calculated z-values ranged from 5.20 to 6.28 degrees C. D-values of a three-strain mixture of A. butzleri in raw ground pork were 18.51 min at 50 degrees C and 2.18 min at 55 degrees C. Mild heat (50 degress C) followed by cold shock (4 or 8 degrees C exposure) had a synergistic lethal effect, reducing more cells than with an individual 50 degrees C treatment or with cold shock temperatures of 12 or 16 degrees C.     

A comparison of three methods for the isolation of Arcobacter spp. from retail raw poultry in Northern Ireland

Recent evidence suggests that arcobacters, especially Arcobacter butzleri, are potential foodborne pathogens, but standardized detection methods have yet to be established. A study was undertaken to determine which of three isolation methods was the most effective for the isolation of Arcobacter spp. from fresh raw poultry. Methods 1 was microaerobic and involved a membrane filtration step followed by plating onto blood agar. Method 2 was also microaerobic and involved enrichment and plating media containing a five-antibiotic cocktail. Method 3 was aerobic and was based on enrichment in a charcoal-based broth containing two antibiotics. Retail poultry samples (n = 50) were obtained from supermarkets in Northern Ireland; the European Community license number was recorded to ensure sample diversity. Presumptive arcobacters were identified using genus-specific and species-specific primers. Methods 1 resulted in the lowest recovery of arcobacters (28% of samples positive). The detection rate for method 2 (68%) was higher than that for method 3 (50%), but the difference was not significant (P > 0.05). Modification of method 3 by plating the enrichment broth at 24 h, as well as at 48 h, increased recovery to 68%. Use of methods 2 and 3 together increased the number of positive samples detected by approximately 25% compared with use of either method alone. A. butzleri was the most commonly isolated species using all methods. Method 3 detected Arcobacter cryaerophilus in more samples (n = 3) than did method 1 and 2 (n = 1). Arcobacter skirrowii was detected by only method 3 (n = 1). In terms of sensitivity, ease of use, and diversity of species recovered, modified method 3 was the overall method of choice.     

One-step polymerase chain reaction-based typing of Arcobacter species

A species-specific PCR assay was developed for the identification of the Arcobacter species, Arcobacter butzleri, Arcobacter cryaerophilus 1A and 1B, and Arcobacter skirrowii. The primers, which amplify the most variable areas of the 23S rRNA gene, were designed to perform species-specific identification by one-step PCR. The DNA sequence of the region from A. cryaerophilus 1B was determined, and the specific pimer for the species was designed. By using one-step PCR containing the mixed primers N.butz, N.c1.A, N.c.1B, and N.ski, species-specific amplifications were detected from the reference strains of A. butzleri, A. cryaerophilus 1A, 1B, and A. skirrowii, respectively. Primers designed in this study were also evaluated on 10 of Japanese field isolates, and all species were identified. This simple one-step PCR assay was found to be a powerful tool for the survey of Arcobacter infection.     

Prevalence and diversity of Arcobacter spp. in the Czech Republic

The aim of this study was to examine 634 samples of chicken, lamb, pork, beef, fish, samples from the intensive animal industry and from poultry for slaughter, as well as from the domestic breeding of poultry, horses, pigs, and lambs, from surface water, and from clinical samples for the presence of Arcobacter. All the samples were examined with a cultivation method, followed by confirmation by multiplex PCR. The method of multiplex PCR applied directly to a liquid medium after enrichment was applied only to the samples with the highest probability of the presence of arcobacters. Arcobacter spp. were detected in 11.8% of the samples, of which A. butzleri, A. cryaerophilus, and A. skirrowii were found in 6.6, 5.1, and 0.2% of the samples, respectively. The sources of the arcobacters were chicken meat from the retail market, intensive animal production facilities, domestic chicken breeding facilities, lamb raising environments, surface water and wastewater, and beef swabs taken in a meat processing factory. No occurrence of arcobacters was identified in the swabs from slaughter turkeys, ducks, and wild poultry. No arcobacters were found in horse and pig breeding environments, on pork, or on the swabs of fish. Forty-two rectal swabs taken from humans were also free of Arcobacter. Seventeen isolates of Arcobacter were further identified by sequencing the 16S rRNA gene. Varied genotypes were observed among A. butzleri from chicken meat and chicken breeds, and A. cryaerophilus from wastewater and chicken breeds. They were similar to the genotypes present in wastewater, porcine feces, human stool, and human blood obtained from databases. Our results revealed that the chicken meat from the retail market is an important source of arcobacters. Cross-contamination during handling of chicken carcass practices could play a key role in the spread of Arcobacter.     

Prevalence of Arcobacter spp. in raw milk and retail raw meats in Northern Ireland

A 1-year study was undertaken to determine the prevalence of Arcobacter spp. in raw milk and retail raw meats on sale in Northern Ireland. Retail raw poultry samples (n = 94), pork samples (n = 101), and beef samples (n = 108) were obtained from supermarkets in Northern Ireland, and raw milk samples (n = 101) were kindly provided by the Milk Research Laboratory, Department of Agriculture and Rural Development, Belfast, Northern Ireland. Presumptive arcobacters were identified by previously described genus-specific and species-specific PCR assays. Arcobacter spp. were found to be common contaminants of retail raw meats and raw milk in Northern Ireland. Poultry meat (62%) had the highest prevalence, but frequent isolations were made from pork (35%), beef (34%), and raw milk (46%). Arcobacter butzleri was the predominant species isolated from retail raw meats and was the only species isolated from raw milk samples. Arcobacter cryaerophilus was detected less frequently, and Arcobacter skirrowii was detected only as a cocontaminant. To our knowledge, this is the first report of Arcobacter spp. prevalence in a diverse range of products of animal origin in Northern Ireland.     

Isolation and characterisation of Arcobacter butzleri from meat

A survey was conducted to determine the prevalence of Arcobacter in ground chicken, pork, beef and lamb meats. Meat samples were enriched in Arcobacter broth (AB) containing cefoperazone, amphotericin and teicoplanin (CAT) supplement. Samples were screened for the presence of Arcobacter spp. using a multiplex polymerase chain reaction (PCR) followed by isolation on blood and selective agar. Arcobacter butzleri was the only species of Arcobacter isolated from 35% of 88 samples of ground meats. A. butzleri was more frequently isolated from poultry (73%) than pork (29%), beef (22%) or lamb (15%) samples. No significant differences were found in the isolation rates and from the different regions sampled. Isolates were characterised by pulsed-field gel electrophoresis (PFGE) using SacII, EagI and SmaI restriction endonucleases. A number of isolates with indistinguishable PFGE fingerprints were found to be epidemiologically related, which may indicate cross-contamination of common types of Arcobacter from different meat species or between meat species. The public health significance of Arcobacter in ground meat needs to be determined.     

Prevalence of Arcobacter and Campylobacter on broiler carcasses during processing

Broiler carcasses (n=325) were sampled in a U.S. commercial poultry processing plant for the prevalence of Arcobacter and Campylobacter at three sites along the processing line: pre-scald, pre-chill and post-chill. Samples (75-125 broilers per site) were collected during five plant visits from August to October of 2004. Arcobacter was recovered from pre-scald carcasses more frequently (96.8%) than from pre-chill (61.3%) and post-chill carcasses (9.6%). Campylobacter was isolated from 92% of pre-scald carcasses, 100% of pre-chill carcasses, and 52% of post-chill carcasses. In total, Arcobacter was isolated from 55.1% (179 of 325), while Campylobacter was isolated from 78.5% (255 of 325) of the carcasses from the three collection sites. For Arcobacter identification, a species-specific multiplex PCR showed that A. butzleri was the most prevalent species (79.1%) followed by A. cryaerophilus 1B (18.6%). A. cryaerophilus 1A was found at low levels (2.3%). PCR identified the most common Campylobacter species as C. jejuni (87.6%) followed by C. coli (12.4%). Overall, significant contamination of broiler carcasses by Arcobacter was observed, although less than that found for Campylobacter. From pre-scald to post-chill, a far greater reduction in Arcobacter numbers was observed than for Campylobacter. Our results for Arcobacter, obtained from the same environment as the closely related pathogen Campylobacter, will aid in the development of control measures for this emerging pathogen.     

Inhibition of Arcobacter butzleri, Arcobacter cryaerophilus, and Arcobacter skirrowii by plant oil aromatics

The inhibitory effect of some plant oil aromatics against three strains of Arcobacter butzleri, two strains of Arcobacter cryaerophilus, and one strain of Arcobacter skirrowii was evaluated. When MICs were determined using the broth macrodilution method, cinnamaldehyde was most inhibitory followed by thymol, carvacrol, caffeic acid, tannic acid, and eugenol (P < 0.001). Sublethal concentrations of the three most potent plant oil aromatics also were examined. Overall, cinnamaldehyde was the most bacteriostatic against all arcobacters tested except A. butzleri when these strains were exposed to the MIC25 of this aromatic aldehyde. The bacteriostatic activities of thymol and carvacrol were concentration and species dependent.     

Occurrence and distribution of Arcobacter species in poultry processing

A total of 16 broiler flocks slaughtered in the morning in eight Belgian poultry slaughterhouses were examined for the presence of Campylobacteraceae. In samples collected before and after chilling, the prevalence of arcobacters was found to be higher than the prevalence of thermophilic campylobacters, with the slaughter procedure used having no clear effect. Two slaughterhouses were selected for a detailed investigation of the occurrence and distribution of arcobacters. Sampling carried out before slaughter revealed that both Arcobacter butzleri and Arcobacter cryaerophilus were commonly present on the slaughter equipment in both plants. These findings indicate inadequate decontamination of the slaughterhouse environment and suggest potential Arcobacter contamination of broiler carcasses through the slaughter equipment. Even before evisceration, contamination levels of hundreds to several thousands of arcobacters per gram of neck skin were detected. It appears unlikely that contamination through slaughter equipment alone explains the high contamination levels found for poultry products. Arcobacters were not isolated from the 30 intestinal tracts sampled for each broiler flock examined. A. cryaerophilus was the only Arcobacter species recovered from the transport crate samples collected before and after washing. Arcobacter contamination during slaughter, either direct (from chicken intestinal content or feces) or indirect (from equipment), was not confirmed. The origin and the precise routes of contamination remain to be determined.