Microbiological quality of water immersion-chilled and air-chilled broilers

Carcass chilling during broiler processing is a critical step in preventing growth of pathogenic and spoilage bacteria. The objective of this study was to compare the microbiological quality of air- and water-chilled broiler carcasses processed at the same commercial facility. For each of four replications, 15 broilers were collected from the same commercial processing line after evisceration, after spraying with cetylpyridinium chloride (a cationic disinfectant), and after air chilling or water immersion chilling (WIC). All carcasses were quantitatively examined for mesophilic aerobic bacteria, Escherichia coli, coliforms, and Campylobacter as well as for the presence of Salmonella and Campylobacter. No significant differences (P > 0.05) were seen between air and water chilling for E. coli or coliforms or for the incidence of Salmonella and Campylobacter. Lower numbers of Campylobacter were recovered from WIC than from air-chilled carcasses (P < 0.05), but the incidence of Campylobacter on WIC carcasses was similar, suggesting that some Campylobacter organisms were injured rather than killed during WIC. In-line spraying with the disinfectant effectively decreased the incidence of Salmonella and Campylobacter on prechilled carcasses; however, cells presumably injured by the sanitizer recovered during chilling. Therefore, on-farm intervention strategies remain critically important in minimizing the spread of microbial contaminants during processing.     

Enumeration of Campylobacter spp. in broiler feces and in corresponding processed carcasses

Twenty north Georgia commercial flocks of broiler chickens sampled in 1995 and 11 flocks sampled in 2001 were tested for Campylobacter spp. Direct plating on Campy-Cefex agar was carried out to determine levels of Campylobacter colonization within each flock through the enumeration of the organism in 50 fresh fecal samples 1 day prior to slaughter. The next morning, these flocks were the first to be processed, and levels of the organism per carcass before the chilling operation (50 carcasses per flock) in 2001 and after the chilling operation (50 carcasses per flock) in both 1995 and 2001 were estimated. Levels of the organism on freshly processed broiler carcasses were estimated by the same methods in 1995 and 2001, and a significant reduction from an average of 10(4.11) CFU per carcass in 1995 to an average of 10(3.05) CFU per carcass in 2001 was observed. Levels of Campylobacter spp. found in production and in processing were not strongly correlative, indicating the existence of complex parameters involving production factors and variables associated with flock transport and the processing of the broilers. The reduction in Campylobacter levels on processed carcasses may have contributed to the reduction in the frequency of human disease observed by the Centers for Disease Control during the same period. These data characterize the distribution of Campylobacter in north Georgia poultry operations and should assist in the development of risk assessment models for Campylobacter spp. The results obtained in this study suggest that the implementation of antimicrobial interventions by the poultry industry has already reduced consumer exposure to the organism.     

Comparison of methods for recovery and enumeration of Campylobacter from freshly processed broilers.

Most traditional Campylobacter detection and enumeration procedures are difficult and time consuming. Estimations of Campylobacter populations by the most probable number (MPN) method are especially laborious. The objective of this collaborative study, performed in duplicate in Agricultural Research Service and Food Safety Inspection Service laboratories, was to compare two MPN procedures (utilizing different selective enrichment broths and plating media) to the direct plating technique for enumeration of Campylobacter from freshly processed (postchill, postdrip) broiler chicken carcasses. Results obtained from the direct plating of carcass rinse samples on Campy-cefex agar were not significantly different (P > 0.05) from an MPN procedure employing Hunt's Campylobacter selective enrichment broth followed by recovery on modified Campylobacter charcoal differential agar. However, both of these procedures provided significantly (P < 0.05) better recovery than a second MPN procedure using Rosef's selective enrichment broth followed by plating on Mueller-Hinton blood agar with antibiotics. The direct plating method offers a more simple, less expensive, more rapid alternative to traditional MPN procedures for estimating Campylobacter populations associated with freshly processed broiler carcasses.     

Prevalence of Salmonella spp. in poultry broilers and shell eggs in Korea

This study was conducted to determine the presence of Salmonella spp. in raw broilers and shell eggs in Korea. In total, 135 dozen shell eggs and 27 raw broilers were tested. None of the egg yolks were found to contain Salmonella organisms but Escherichia coli, Escherichia hermanii, and Citrobacter freundii were isolated from egg shells. Salmonella spp. were detected in 25.9% of raw broilers, and Salmonella serotypes isolated from raw broilers were Salmonella Enteritidis, Salmonella Virchow, and Salmonella Virginia. D-values and antibiotic resistance of Salmonella isolates were also investigated. D-values of Salmonella enteritidis, Salmonella Virginia, and Salmonella Virchow in tryptic soy broth at 55 degrees C were 2.36, 2.13, and 0.70 min and 0.53, 0.37, and 0.20 min at 60 degrees C, respectively. All Salmonella isolates showed multiple antibiotic resistance patterns and were resistant to penicillin and vancomycin. One strain of Salmonella Enteritidis showed resistance to 12 antibiotics used in this study.     

Antimicrobial resistance in Campylobacter jejuni from broilers and broiler house environments in Norway

Antimicrobial susceptibility in Campylobacter jejuni collected from the environment outside four broiler houses (n = 63) and from the environment inside these broiler houses (including broiler droppings) (n = 36) from May to September 2004 was studied and compared with isolates from Norwegian broilers analyzed within the frame of the Norwegian monitoring program of antimicrobial resistance in feed, food, and animals (NORM-VET) in 2004 (n = 75). The MICs of oxytetracycline, ampicillin, erythromycin, gentamicin, enrofloxacin, and nalidixic acid were obtained by the broth microdilution method VetMIC. The present study, which to our knowledge is the first Norwegian study on the occurrence of antimicrobial resistance in Campylobacter spp. from the environment of broiler houses, revealed a very low occurrence of antimicrobial resistance in C. jejuni from the broilers and broiler house environments studied. All isolates originating from the four broiler houses studied were susceptible to all the antimicrobial agents tested, except for one isolate from the outdoor environment (courtyard soil), which was resistant to oxytetracycline (MIC, 8 mg/liter). For the isolates from broilers (NORM-VET), low prevalences of resistance to oxytetracycline (1.3%) and ampicillin (4%) were observed. No quinolone resistance was observed. The results for the broiler isolates are in agreement with the earlier findings of a very low prevalence of resistance in Campylobacter from broilers in Norway, which reflects the low usage of antimicrobials in Norwegian broiler production. Furthermore, the present data are in accordance with antimicrobial susceptibility data for C. jejuni from domestically acquired human cases.     

Prevalence of the Campylobacter multi-drug efflux pump (CmeABC) in Campylobacter spp. Isolated from freshly processed Turkeys

The prevalence of the Campylobacter multi-drug efflux pump (CmeABC) was evaluated in Campylobacter isolates recovered from freshly processed turkeys at two Midwestern processing plants. A total of 94 Campylobacter isolates recovered from processed turkeys were examined using polymerase chain reaction (PCR) to determine the presence of the multi-drug efflux pump genes cmeA, cmeB, and cmeC. Results from this study found that 51% of all isolates tested were positive for CmeABC. 46.6% of these positive isolates were from plant A and 55.1% from plant B. Differences were observed in the prevalence of individual genes found among Campylobacter isolates from each plant. Additional analysis found that among the isolates positive for CmeABC, 85.5% were identified as C. jejuni and 14.5% identified as C. coli. There was a relatively high occurrence of the Campylobacter multi-drug efflux pump genes in Campylobacter spp. recovered from processed turkeys, however, the presence of the genes could not be significantly linked to antimicrobial resistance observed in the test strains and suggests that the CmeABC genes are only one factor associated with antimicrobial resistance in Campylobacter spp.     

Prevalence and characteristics of Shiga toxin-producing Escherichia coli, Salmonella spp. and Campylobacter spp. isolated from slaughtered sheep in Switzerland

Caecum samples collected from 653 slaughtered sheep from two Swiss abattoirs were examined. The aim of this study was: (i) to determine the prevalence of Shiga toxin-producing Escherichia coli (STEC), Salmonella spp. and Campylobacter spp.; (ii) to further characterize isolated strains; and (iii) to discuss the results obtained with their relevance to food safety. The percentage of samples testing positive for STEC by a polymerase chain reaction was 29.9%. The prevalence of positive Salmonella spp. samples was 11.0% and of Campylobacter spp. 17.5%. In 55.3% of the 76 isolated non-O157 STEC strains, stx2 variants (mostly stx2d) were detected. Additional virulence factors were harbored by 55.3% of the STEC strains, 10.5% of them being eae positive, 55.3% ehxA positive and 2.6% astA positive. All isolated salmonella were identified as Salmonella enterica subsp. diarizonae serovar 61:k:1,5,(7). Pulsed-field gel electrophoresis (PFGE) was performed for genotyping and 22 different restriction endonuclease digestion profiles were found among these strains for the different farms of origin. Of the 114 isolated Campylobacter spp. strains, 64.9% were shown to be Campylobacter jejuni and 35.1% Campylobacter coli, nine strains showed resistance against tetracycline, ciprofloxacin/nalidixic acid or streptomycin. In conclusion, sheep are a reservoir for the pathogens of latent zoonoses as non-O157 STEC, S. enterica subsp. diarizonae and Campylobacter spp. The maintenance of slaughter hygiene is consequently of crucial importance. It can be measured in daily practice by "slaughter-process-controls" and regular microbiological monitoring of carcasses. These are valuable tools for verifying slaughter hygiene according to hazard analysis critical control point principles.     

Reduction in flock prevalence of Campylobacter spp. in broilers in Norway after implementation of an action plan

An action plan against thermophilic Campylobacter spp. in Norwegian broilers was implemented in May 2001. The action plan consists of three parts: a surveillance program including all Norwegian broiler flocks slaughtered before 50 days of age, a follow-up advisory service on farms delivering flocks positive for Campylobacter spp., and surveys of broiler meat products at the retail level. This article presents results covering the inclusive 3-year period between 2002 and 2004. During this period, a total of 10,803 flocks from 562 broiler farms were tested; altogether, 521 (4.8%) of the flocks were identified as positive for Campylobacter spp., primarily Campylobacter jejuni. The positive flocks originated from 257 (45.7%) of the farms. During the period 2002 to 2004, there was a large and steady reduction in flock prevalence, from 6.3% in 2002 to 3.3% in 2004. Also, the proportion of farms producing flocks positive for Campylobacter spp. each year reduced substantially, from 28.4% in 2002 to 17.8% in 2004. The proportion of flocks positive for Campylobacter spp. varied considerably with season and region. The action plan is a successful collaboration between academia, regulatory agencies, and the poultry industry that has resulted in a significant reduction in the number of broiler carcasses positive for Campylobacter spp. on the market. The temporal associations between implementation of the control program and the drop in the number of infected chickens and contaminated carcasses indicate that this collaborative action plan has been instrumental in achieving the goals of enhancing food safety.     

A quantitative analysis of cross-contamination of Salmonella and Campylobacter spp. via domestic kitchen surfaces

Epidemiological data indicate that cross-contamination during food preparation in the home contributes noticeably to the occurrence of foodborne diseases. To help prevent such occurrences, the inclusion of a cross-contamination model in exposure assessments would aid in the development and evaluation of interventions used to control the spread of pathogenic bacteria. A quantitative analysis was carried out to estimate the probability of contamination and the levels of Salmonella and Campylobacter spp. on salads as a result of cross-contamination from contaminated chicken carcasses via kitchen surfaces. Data on the prevalence and numbers of these bacteria on retail chicken carcasses and the use of unwashed surfaces to prepare foods were collected from scientific literature. The rates of bacterial transfer were collected from laboratory experiments and literature. A deterministic approach and Monte Carlo simulations that incorporated input parameter distributions were used to estimate the contamination of the product. The results have shown that the probability of Campylobacter spp. contamination on salads is higher than that of Salmonella spp., since both the prevalence and levels of Campylobacter spp. on chicken carcasses are higher than those of Salmonella spp. It is realistic to expect that a fraction of the human exposure to Campylobacter spp., in particular, originates from cross-contamination in private kitchens during food handling. The number of human campylobacteriosis cases could be reduced either by reducing the degree of Campylobacter spp. contamination on chicken carcasses or by improving the hygiene in private kitchens. To eliminate the cross-contamination route, it is important to use separate surfaces or to properly wash the surfaces during the preparation of raw and cooked foods or ready-to-eat foods.     

Occurrence of Campylobacter spp., Salmonella spp. and shiga toxin-producing Escherichia coli in inline milk filters from Swedish dairy farms

This study investigated the occurrence of shiga toxin-producing Escherichia coli (STEC), thermotolerant Campylobacter spp. and Salmonella spp. in Swedish dairy milk. A total of 302 inline milk filters were analyzed. Salmonella was not isolated from any filters. Polymerase chain reaction screening detected thermotolerant Campylobacter in 30.5% of the milk filters analyzed and it was isolated from 12.6% of filters. The stx genes (stx ₁, stx ₂, or both) were screened from 71% of the filters and STEC was isolated from 14% of these. Of the STEC isolates, 21 contained the stx ₁ gene, 19 the stx ₂ gene, and five a combination of both stx ₁ and stx ₂ genes. Whole genome sequence typing on 34 of the 45 STEC showed that they belonged to 21 different serotypes, of which STEC O145:H28 was the most common (2%). STEC O157:H7 was only found from one (0.3%) of the filters. A combination of stx ₂ and eae genes was found from 0.7% of the total number of inline milk filters analyzed, while stx _2a was found in 24% of the whole genome-sequenced isolates. There was a significant positive correlations between number of animals per farm and presence of pathogens on milk filters.     

Effect of fecal contamination and cross-contamination on numbers of coliform, Escherichia coli, Campylobacter, and Salmonella on immersion-chilled broiler carcasses

The effect of prechill fecal contamination on numbers of bacteria on immersion-chilled carcasses was tested in each of three replicate trials. For each trial, 16 eviscerated broiler carcasses were split into 32 halves and assigned to one of two groups. Cecal contents (0.1 g inoculated with Campylobacter and nalidixic acid-resistant Salmonella) were applied to each of eight halves in one group (direct contamination) that were placed into one paddle chiller (contaminated), whereas the other paired halves were placed into another chiller (control). From the second group of eight split birds, one of each paired half was placed in the contaminated chiller (to determine cross-contamination) and the other half was placed in the control chiller. Postchill carcass halves were sampled by a 1-min rinse in sterile water, which was collected and cultured. Bacterial counts were reported as log CFU per milliliter of rinsate. There were no significant statistical differences (paired t test, P < 0.05) from direct contamination for coliforms (mean 3.0 log CFU) and Escherichia coli (mean 2.7 log CFU), although Campylobacter numbers significantly increased from control values because of direct contamination (1.5 versus 2.1 log CFU), and the incidence increased from 79 to 100%. There was no significant effect of cross-contamination on coliform (mean 2.9 log CFU) or E. coli (mean 2.6 log CFU) numbers. Nevertheless, Campylobacter levels were significantly higher after exposure to cross-contamination (1.6 versus 2.0 log CFU), and the incidence of this bacterium increased from 75 to 100%. Salmonella-positive halves increased from 0 to 42% postchill because of direct contamination and from 0 to 25% as a result of cross-contamination after chilling. Water samples and surface swabs taken postchill from the contaminated chiller were higher for Campylobacter than those taken from the control chiller. Immersion chilling equilibrated bacterial numbers between contaminated and control halves subjected to either direct contamination or cross-contamination for coliforms and E. coli. Campylobacter numbers, Campylobacter incidence, and Salmonella incidence increased because of both direct contamination and cross-contamination in the chiller. Postchill E. coli numbers did not indicate which carcass halves were contaminated with feces before chilling.     

双重PCR 方法检测沙门氏菌和空肠弯曲菌

为建立能够同时检测食品中沙门氏菌和空肠弯曲菌的双重PCR 方法。采用沙门氏菌鞭毛基因fimY 和空肠弯曲菌马尿酸酶基因hipO 设计特异性引物,并对影响PCR 扩增的主要因素——引物浓度、退火温度、Mg2+ 浓度因素进行优化,比较单一PCR 和双重PCR 的检测效果。结果表明：采用单一PCR 法检测沙门氏菌和空肠弯曲菌时,灵敏度分别可达到3.98pg 和4.05pg;而采用双重PCR 检测时,灵敏度较单一PCR 法有所下降,沙门氏菌和空肠弯曲菌检出限量分别为398pg 和40.5pg。本研究建立的特异性强和灵敏度高的双重PCR 检测方法,可为实现食品中沙门氏菌和空肠弯曲菌的同时检测提供新方法。     

Prevalence and numbers of Salmonella and Campylobacter spp. on raw,whole chickens in relation to sampling methods

Salmonella and Campylobacter continue to be major foodborne pathogens and raw poultry is considered to be an important source of these bacteria. In this study, the prevalence and numbers of Salmonella and Campylobacter spp. in relation to isolation/sampling methods were determined in 241 whole raw chickens purchased from retail outlets in England during the winters of 1998/1999 (101 chickens) and 1999/2000 (140 chickens). The packaging of the 140 chickens was also examined for the presence of the above pathogens. The prevalence and numbers of enterococci were examined in 21 of the 101 chickens. In total, Salmonella and Campylobacter spp. were present in 25% and 83% of the chickens, respectively. Salmonella were isolated from a sample representing both the inside and outside of the packaging in 19% of the chickens, while the corresponding figure for Campylobacter spp. was 56%. Both of these pathogens were isolated from the outside of the packaging in 6% of the chickens. Salmonella was more frequently isolated from samples containing chicken skin in comparison with those containing carcass-rinse fluid only. Two chickens (0.8%) were positive for Salmonella by direct enumeration methods with contamination levels of log10 3.8 and 4.5 colony forming units (cfu) per carcass, respectively. The most prevalent serotypes were S. Hadar, S. Enteritidis and S. Indiana and two different serotypes were identified in 5/20 salmonella-positive chickens. Resistance to at least one antibiotic was found in 70% of the strains, 46% were multiresistant (resistant to > or = four drugs) and 52% showed a lowered susceptibility to ciprofloxacin. The likelihood of isolating Campylobacter spp. from neck-skin, carcass-rinse or carcass-rinse plus whole skin samples was similar, Campylobacter spp. were found in higher levels in carcass-rinse or carcass-rinse plus whole skin samples than in neck-skin. The log10 cfu of Campylobacter spp. were 2.70-4.99 in 18% of the chickens and 5.00-6.99 in 20%. Campylobacter isolates (425) comprised Campylobacter jejuni (98%) and C. coli (2%) and 98 different sero/phagetypes of these two species were identified. Resistance to at least one antibiotic was found in 73% of the strains and 13% were multiresistant. Thirteen percent of the strains showed lowered susceptibility to ciprofloxacin, while 4.9% were resistant to erythromycin. Vancomycin-resistant enterococci (VRE), able to grow on agar containing 15 mg l(-1) vancomycin (VRE15), were present in 19 chickens. The log10 cfu of VRE15 was 2.90-3.99 in 10 chickens and between 4.00 and 4.99 in two chickens. The data presented here contribute to risk assessment and highlight the need to continue to emphasise the safe handling of raw retail poultry.     

Prevalence and risk factors for Salmonella and Campylobacter spp. carcass contamination in turkeys slaughtered in Quebec, Canada

An observational study was conducted to estimate prevalence and risk factors for carcass contamination by Salmonella and Campylobacter spp. in 60 lots of turkey slaughtered over 10 months in the province of Quebec, Canada. Carcass contamination was evaluated by the carcass rinse technique for about 30 birds per lot. Exposure to potential risk factors was evaluated with questionnaires, meteorological data, and cecal cultures. Multivariable binomial negative regression models were used for risk factor analysis. Prevalence of Salmonella-positive carcasses was 31.2% (95% confidence interval, 22.8 to 39.5%). Variables positively associated (P < or = 0.05) with the proportion of lot-positive carcasses were > or =0.5% of carcass condemnation due to various pathologies, cecal samples positive for Salmonella, low wind speed during transportation, closure of lateral curtains of truck during transportation, and slaughtering on a weekday other than Monday. When only Salmonella-positive cecal culture lots were considered, the proportion of carcasses positive for Salmonella was significantly higher in lots exposed to a >5 degrees C outside temperature variation during transportation, slaughtered on a weekday other than Monday, and in which > or = 4% of carcasses had visible contamination. Prevalence of Campylobacter-positive carcasses was 36.9% (95% confidence interval, 27.6 to 46.3%). The proportion of positive carcasses was significantly higher in lots with Campylobacter-positive cecal cultures and lots undergoing > or =2 h of transit to slaughterhouse. For lots with Campylobacter-positive cecal cultures, variables significantly associated with an increased incidence of carcass contamination were de4% of carcasses with visible contamination, crating for > or =8 h before slaughtering, and no antimicrobials used during rearing.     

Contamination of Campylobacter spp. from foodstuff

Prevalence of Campylobacter spp. in foodstuff. All campylobacter spp. were identified as thermophilic campylobacter jejuni. campylobacter jejuni were most commonly isolated from crude birds samples (37%), both cooled and frozen. Campylobacter jejuni were recovered in 57% meat and semifinished items samples with contamination levels from the cooled samples of 270+/-470 colony forming units (cfu) per 100 g, frozen samples of 238+/-346 per 100 g and in 351% offal samples, with a contamination level from the cooled samples 100+/-360 per 100 g.     

Salmonella spp. shedding by alberta beef cattle and the detection of Salmonella spp. in ground beef

Breeder cows, cattle recently arrived at feedlots, and cattle about to be shipped for slaughter were tested for Salmonella spp. No Salmonella spp. were detected in fecal samples from breeding cows. Nineteen of 1,000 (1.9%) fecal samples from recently arrived feedlot cattle were positive for Salmonella spp. compared to only 2 of 1,000 (0.2%) fecal samples taken within 2 weeks of slaughter. The positive fecal samples were collected in 5 of 50 (10%) "recent arrival" pens tested and in 1 of 50 (2%) pens tested within 2 weeks of slaughter. The serotypes isolated were Salmonella Agona, Salmonella Enteritidis, Salmonella Typhimurium DT104, and Salmonella 4,5,12:i:-. Ground beef samples purchased from retail outlets throughout Alberta were processed for Salmonella spp. Thirteen of 1,002 (1.3%) samples were positive for Salmonella spp. The serotypes isolated from ground beef were Salmonella Anatum, Salmonella Heidelberg, Salmonella Montevideo, Salmonella Typhimurium, Salmonella Typhimurium var. Copenhagen, and Salmonella Rough-O:i:1,2. The antibiotic resistance and pulsed-field electrophoresis gel macrorestriction patterns of all isolates were compared.     

Prevalence and risk factors for Salmonella and Campylobacter spp. carcass contamination in broiler chickens slaughtered in Quebec, Canada

An observational study was conducted to estimate prevalence and risk factors for Salmonella and Campylobacter spp. carcass contamination in broiler chickens. Eighty-two lots were sampled in four slaughterhouses located in the province of Québec, Canada, over a 10-month period. Carcass contamination was evaluated by the carcass rinse technique for about 30 birds per lot. Exposure to potential risk factors was evaluated based on data from questionnaires, meteorology, and cecal cultures. Multivariable binomial negative regression models were used for risk factor analysis at the lot level. The prevalence of Salmonella-positive carcasses was 21.2% (95% confidence interval: 15.7 to 26.7%). Significant risk factors (P < 0.05) associated with a higher proportion of positive carcasses within lots were Salmonella-positive cecal culture, low rainfall during transportation to the slaughterhouse, temperature of > or = 0 degree C during transportation to the slaughterhouse, and a > or = 4-h waiting period in shipping crates before slaughtering. The prevalence of Campylobacter-positive carcasses was 35.8% (95% confidence interval: 27.1 to 44.5%). Lots containing birds with Campylobacter-positive cecal culture results, lots of birds that were slaughtered at the end of the week, and lots with at least 20% of birds with digestive contents detected in the jejunum at time of slaughtering had a significantly higher proportion (P < 0.05) of contaminated carcasses. These results support the importance of preharvest control measures implemented during rearing to reduce contamination of the final product. Weather during transportation to slaughter and the day of the week that birds were slaughtered also were associated with carcass contamination; further studies are needed to determine the underlying mechanisms by which these factors influence carcass contamination.     

Prevalence and antibiotic susceptibility of Salmonella isolated from beef animal hides and carcasses

This study determined the prevalence of Salmonella on beef animal hides and carcasses and antimicrobial susceptibility profiles against a panel of 13 antibiotics. In each of the eight commercial packing facilities, of which five processed primarily heifers and steers and the remaining three processed primarily cows and bulls, hide and carcass sponge swab samples were obtained immediately before hide removal and before carcass chilling, respectively. Overall, prevalence of Salmonella on external surfaces (hides) of cattle was 15.4% (49 of 319), whereas prevalence after dehiding and other slaughtering/dressing processes, including the application of decontamination treatments, was, as expected, reduced (P < 0.05) to 1.3% (4 of 320) on carcass surfaces. From 53 total Salmonella-positive hide and carcass samples, 526 biochemically confirmed isolates were obtained to determine antimicrobial susceptibility profiles. Of 53 Salmonella-positive samples, individually, 24 (45.3%), 17 (32.1%), 17 (32.1%), 11 (20.8%), 8 (15.1%), 8 (15.1%), 8 (15.1%), 4 (7.5%), and 2 (3.8%) samples yielded at least one isolate resistant to amoxicillin/clavulanic acid, tetracycline, streptomycin, sulfonamides, ampicillin, ampicillin/sulbactam, chloramphenicol, gentamicin, and trimethoprim/sulfamethoxazole, respectively. None of the Salmonella-positive samples yielded an isolate resistant to ceftriaxone, ciprofloxacin, enrofloxacin, or levofloxacin. Although none of the samples yielded an isolate simultaneously resistant to three or four antimicrobials, a total of eight samples yielded at least one isolate resistant to five or more antimicrobials tested. Included among the 18 group B-positive samples were three samples that, individually, yielded at least one Salmonella Typhimurium var. Copenhagen DT104 isolate resistant to at least six antimicrobials tested. Results from this study support current prudent therapeutic and subtherapeutic antimicrobial use recommendations.     

Thermophilic Campylobacter spp. in salad vegetables in Malaysia

The main aim of this study was to combine the techniques of most probable number (MPN) and polymerase chain reaction (PCR) for quantifying the prevalence and numbers of Campylobacter spp. in ulam, a popular Malaysian salad dish, from a traditional wet market and two modern supermarkets in Selangor, Malaysia. A total of 309 samples of raw vegetables which are used in ulam were examined in the study. The prevalences of campylobacters in raw vegetables were, for supermarket I, Campylobacter spp., 51.9%; Campylobacter jejuni, 40.7%; and Campylobacter coli, 35.2%: for supermarket II, Campylobacter spp., 67.7%; C. jejuni, 67.7%; and C. coli, 65.7%: and for the wet market, Campylobacter spp., 29.4%; C. jejuni, 25.5%; and C. coli, 22.6%. In addition Campylobacter fetus was detected in 1.9% of raw vegetables from supermarket I. The maximum numbers of Campylobacter spp. in raw vegetables from supermarkets and the wet market were >2400 and 460 MPN/g, respectively.     

Survey of thermotolerant Campylobacter spp. and Yersinia spp. in three surface water sources in Norway.

We investigated the occurrence of thermotolerant Campylobacter and Yersinia spp. in three surface water sources in Norway which represented different levels of pollution and eutrophication. Samples were collected every fortnight during a 14-month period. In addition, samples from 100 private wells were examined for campylobacters only. Campylobacter was recovered from 42 (43.8%) of the 96 samples of surface water, whereas Yersinia spp. were isolated from four (4.2%) of the samples. Campylobacter was not isolated from the well water samples. The highest isolation rate of Campylobacter was obtained from the two most polluted water sources. The proportion of positive samples was significantly higher in the autumn (71.4%) than in the spring (36.4%) or summer (22.2%). The highest overall isolation rate was obtained at water temperatures ranging from 2.1 to 8.0 degrees C, and the lowest at temperatures greater than 15 degrees C. Logistic regression analysis showed a highly significant relationship between the prevalence of Campylobacter and the number of three types of indicator bacteria: faecal coliforms, faecal streptococci and sulphite-reducing clostridia. Of the 60 Campylobacter isolates obtained, 51.7% belonged to C. jejuni biotype 1, 20.0% belonged to C. jejuni biotype 2, 21.7% to C. coli, 3.3% to C. lari and 3.3% were non-typable. All four Yersinia isolates were non-pathogenic variants.