water-borne outbreak of campylobacter laridis-associated gastroenteritis. | | 1987 | 2880002 |
an epidemiological study of selected calf pathogens on holstein dairy farms in southwestern ontario. | fecal samples from calves on 78 randomly selected holstein dairy farms in southwestern ontario were screened for salmonella, campylobacter jejuni/coli, enteropathogenic escherichia coli, rotavirus and coronavirus. based on the observed prevalence, 22% of farms had calves infected with salmonella, 13% with campylobacter jejuni/coli, 41% with enteropathogenic e. coli, 19% with rotavirus and 5% with coronavirus. these estimates can be modified, using a method developed by mullen and prost (1983) fo ... | 1986 | 3017528 |
frequency of escherichia coli o157:h7 isolation from stool specimens. | during a 6-month period, 7252 faeces specimens were examined for escherichia coli serotype o157:h7. forty-nine specimens (0.7%) from 19 patients yielded this organism. escherichia coli o157:h7 was the third most frequently isolated bacterial pathogen, following campylobacter jejuni and (or) salmonella sp. although regional variation between laboratories determined whether campylobacter jejuni or salmonella was the primary bacterial pathogen isolated, e. coli o157:h7 was consistently isolated mor ... | 1987 | 3319115 |
campylobacter colitis in ranch mink in ontario. | outbreaks of colitis, where campylobacter jejuni and campylobacter coli were the only pathogens isolated occurred in weanling mink (mustella vision) on two commercial mink ranches in ontario. lesions were restricted to the proximal colon and were characterized by multiple 1 mm focal or 1 mm linear erosions/ulcers in the region 2 cm distal to the ileal-colonic junction. histological changes included thickening of the colonic mucosa, inflammatory cell infiltrate in the lamina propria and submucosa ... | 1986 | 3742356 |
rate of campylobacter spp. isolation in three regions of ontario, canada, from 1978 to 1985. | isolation rates of campylobacter spp. were analyzed for an 8-year period, 1978 through 1985. three laboratories of the ontario ministry of health examined 146,842 human feces samples for bacterial pathogens, including campylobacter jejuni and campylobacter coli. campylobacter spp. were isolated from 5,580 specimens (3.8%), with monthly isolation rates ranging from 1.1 to 7.4%. the data showed a seasonal distribution of isolations, with peaks during the summer months (june to september). most inf ... | 1986 | 3771774 |
campylobacter fetus in artificial insemination unit and slaughterhouse bulls in ontario. | preputial fluid samples were collected from 90 bulls in two ontario artificial insemination units using a penial glove swab technique previously developed by one of us for use in donor bulls. no campylobacter fetus organisms were identified from the prepuce or from samples of semen collected at the same time from these bulls. the distal genitalia of 200 bulls were collected at a slaughter house. one isolation of a campylobacter fetus subspecies venerealis was obtained on a culture from the forni ... | 1985 | 3893662 |
premature labor and neonatal sepsis caused by campylobacter fetus, subsp. fetus--ontario. | | 1984 | 6431256 |
incidence of campylobacter jejuni in fresh eviscerated whole market chickens. | | 1981 | 7296414 |
the distribution of foodborne disease by risk setting--ontario. | | 1998 | 9611410 |
compliance with nccls approved standard m22-a2 for bacteriologic media quality assurance: a survey of 124 ontario microbiology laboratories. | the purpose of this qmp-ls patterns-of-practice survey was to determine quality assurance (qa) processes used in ontario for purchased and in-house culture media, and compliance with recommended practices. | 2002 | 11821168 |
walkerton, 2 years later: "memory fades very quickly". | | 2002 | 12041857 |
enteric illness in ontario, canada, from 1997 to 2001. | enteric illness is a common problem worldwide. in ontario (population of 11.4 million, 2001 census of canada), laboratory-confirmed cases of "reportable" enteric diseases are reported to local health units. public health staff members investigate these illnesses and subsequently report details to the ministry of health and long-term care through an electronic reporting system. from 1997 to 2001, 44,451 sporadic cases of illness attributable to eight enteric pathogens (campylobacter, salmonella, ... | 2003 | 12800994 |
characterization of waterborne outbreak-associated campylobacter jejuni, walkerton, ontario. | | 2003 | 14609457 |
use of the oxford multilocus sequence typing protocol and sequencing of the flagellin short variable region to characterize isolates from a large outbreak of waterborne campylobacter sp. strains in walkerton, ontario, canada. | the walkerton (ontario, canada) outbreak of waterborne escherichia coli o157:h7 and campylobacter jejuni was quite limited in both space and time, making it a good model for exploring the utility of different typing and subtyping methods for the characterization of relationships among isolates of these organisms. we have extended previous work with these organisms through analysis by the oxford multilocus sequence typing (mlst) and the flagellin short variable region (fla-svr) sequencing methods ... | 2005 | 15872226 |
prevalence of zoonotic agents in dogs visiting hospitalized people in ontario: implications for infection control. | visitation of hospitalized people by dogs is becoming commonplace, but little is known about the potential health risks of introducing dogs to healthcare settings. this cross-sectional study evaluated the prevalence of zoonotic agents in a group of 102 visitation dogs from a variety of sources across ontario. between may and july 2004, owners were interviewed by a standardized questionnaire while dogs underwent a standardized physical examination. one specimen of faeces, hair-coat brushings and ... | 2006 | 16466831 |
temperate bacteriophages affect pulsed-field gel electrophoresis patterns of campylobacter jejuni. | the recently sequenced genome of campylobacter jejuni rm1221 revealed the presence of three integrated bacteriophage-like elements. in this study, genes from the first element, a mu-like bacteriophage, were amplified by pcr and used to probe pulsed-field gels of clinical c. jejuni strains obtained from a waterborne outbreak (ontario, canada, 2000). these highly similar strains differed only by their pulsed-field gel electrophoresis (pfge) patterns due to an apparent insertion or deletion of a 40 ... | 2007 | 17135440 |
pathogen and indicator variability in a heavily impacted watershed. | water samples were collected from 36 locations within the grand river watershed, in southwestern ontario, canada from july 2002 to december 2003 and were analyzed for total coliforms, fecal coliforms, escherichia coli, escherichia coli o157:h7, and thermophilic campylobacter spp. a subset of samples was also analyzed for cryptosporidium spp., giardia spp., culturable human enteric viruses, and clostridium perfringens. storm and snowmelt events were sampled at two locations including a drinking w ... | 2007 | 17674573 |
comparison of agar dilution and e-test for antimicrobial susceptibility testing of campylobacter coil isolates recovered from 80 ontario swine farms. | the primary aim of this study was to evaluate the level of agreement of the e-test for in vitro antimicrobial susceptibility testing of campylobacter coli using the agar dilution technique, which is the approved method. a convenience sample of 80 ontario swine farms was chosen for this study; each farm was visited from january to june 2004. a total of 233 isolates of c. coli were tested for susceptibility to 10 antimicrobials by agar dilution and the e-test. performance of the tests was evaluate ... | 2008 | 18505206 |
antibiotic resistance of campylobacter jejuni and campylobacter coli isolated from hog, beef, and chicken carcass samples from provincially inspected abattoirs in ontario. | campylobacterjejuni is one of the most common causes of bacterial foodborne infection in the united states, and there are reports of resistance of campylobacter spp. to antimicrobial agents used for the treatment of gastroenteritis. the purpose of this study was to determine the antimicrobial resistance patterns of campylobacter spp. isolated from hog, beef, and chicken carcasses from provincially inspected abattoirs in ontario. the agar dilution method was performed to measure antimicrobial res ... | 2006 | 16416896 |
the walkerton health study. | the contamination of the walkerton, ontario, municipal water with e. coli o157:h7 and campylobacter in may 2000 resulted in at least 2,300 cases of gastrointestinal illness. there were 28 confirmed cases of hemolytic uremic syndrome, the most severe kidney complication. the provincial ministry of health and long-term care determined that a study needed to be conducted on the long-term health effects associated with drinking the contaminated water. the walkerton health study, a seven-year project ... | 2005 | 16035513 |
seasonal relationships among indicator bacteria, pathogenic bacteria, cryptosporidium oocysts, giardia cysts, and hydrological indices for surface waters within an agricultural landscape. | the south nation river basin in eastern ontario, canada is characterized by mixed agriculture. over 1600 water samples were collected on a bi-weekly basis from up to 24 discrete sampling sites on river tributaries of varying stream order within the river basin between 2004 and 2006. water samples were analyzed for: densities of indicator bacteria (escherichia coli, clostridium perfringens, enterococci, total and fecal coliforms), the presence of pathogenic bacteria (listeria monocytogenes, e. co ... | 2009 | 19339033 |
risk of hypertension and reduced kidney function after acute gastroenteritis from bacteria-contaminated drinking water. | the long-term health consequences of acute bacterial gastroenteritis remain uncertain. we studied the risk of hypertension and reduced kidney function after an outbreak of acute gastroenteritis due to contamination of a regional drinking water supply with escherichia coli o157:h7 and campylobacter species. | 2005 | 15923490 |
syndromic surveillance of gastrointestinal illness using pharmacy over-the-counter sales. a retrospective study of waterborne outbreaks in saskatchewan and ontario. | to ascertain if monitoring over-the-counter (otc) drug sales could provide a timely syndromic surveillance method of detecting outbreaks of gastrointestinal illness. | 2004 | 15622795 |
cost analysis and antimicrobial susceptibility testing comparing the e test and the agar dilution method in campylobacter jejuni and campylobacter coli. | although numerous reports have compared the antimicrobial susceptibility of campylobacter spp., controversy still exists about the use of the e test as an alternative to the agar dilution method suggested by the clinical and laboratory standards institute. mics of 8 antimicrobials were determined using the e test and agar dilution methods for 103 campylobacter jejuni and campylobacter coli isolates from fresh chicken randomly purchased from stores in 3 southern ontario counties. overall, 72.6% o ... | 2009 | 19748428 |
heavy rainfall and waterborne disease outbreaks: the walkerton example. | recent research indicates that excessive rainfall has been a significant contributor to historical waterborne disease outbreaks. the meteorological service of canada, environment canada, provided an analysis and testimony to the walkerton inquiry on the excessive rainfall events, including an assessment of the historical significance and expected return periods of the rainfall amounts. while the onset of the majority of the walkerton, ontario, escherichia coli o157:h7 and campylobacter outbreak ... | 2004 | 15371222 |
an outbreak of acute bacterial gastroenteritis is associated with an increased incidence of irritable bowel syndrome in children. | acute bacterial gastroenteritis is associated with subsequent post-infectious irritable bowel syndrome (pi-ibs) in adults. less is known about this relationship in children. in may 2000, contamination of municipal water by escherichia coli 0157:h7 and campylobacter species caused a large outbreak of acute gastroenteritis in walkerton, ontario. we assessed this association among a cohort of children enrolled in the walkerton health study (whs). | 2010 | 20179687 |
the occurrence of campylobacter in river water and waterfowl within a watershed in southern ontario, canada. | quantitative pcr and a culture method were used to investigate campylobacter occurrence over 3 years in a watershed located in southern ontario, canada that is used as a source of drinking water. | 2010 | 20408936 |
knowledge and attitudes toward food safety and use of good production practices among canadian broiler chicken producers. | provincial broiler-chicken marketing boards in canada have recently implemented an on-farm food safety program called safe, safer, safest. the purpose of this study was to measure broiler chicken producers' attitudes toward the program and food safety topics and use of highly recommended good production practices (gpp). mailed and web-based questionnaires were administered to all producers registered in british columbia, ontario, and quebec in 2008. the response percentage was 33.2% (642 of 1,93 ... | 2010 | 20615340 |
assessing levels of pathogenic contamination in a heavily impacted river used as a drinking-water source. | this paper describes initial results from a research program that aims to gain greater understanding of sources of pathogens and the environmental factors that influence their survival and transport in watersheds. an additional goal is to enhance the ability to predict potential levels of pathogenic microorganisms arriving at drinking-water treatment plant intakes. the objectives will be supported by an intensive monitoring program examining the temporal and spatial variability of pathogens in a ... | 2004 | 15371219 |
long term risk for hypertension, renal impairment, and cardiovascular disease after gastroenteritis from drinking water contaminated with escherichia coli o157:h7: a prospective cohort study. | to evaluate the risk for hypertension, renal impairment, and cardiovascular disease within eight years of gastroenteritis from drinking water contaminated with escherichia coli o157:h7 and campylobacter. | 2010 | 21084368 |
estimating potential environmental loadings of cryptosporidium spp. and campylobacter spp. from livestock in the grand river watershed, ontario, canada. | exposure to waterborne pathogens in recreational or drinking water is a serious public health concern. thus, it is important to determine the sources of pathogens in a watershed and to quantify their environmental loadings. the natural variability of potentially pathogenic microorganisms in the environment from anthropogenic, natural, and livestock sources is large and has been difficult to quantify. a first step in characterizing the risk of nonpoint source contamination from pathogens of lives ... | 2004 | 15260337 |
a fatal waterborne disease epidemic in walkerton, ontario: comparison with other waterborne outbreaks in the developed world. | an estimated 2,300 people became seriously ill and seven died from exposure to microbially contaminated drinking water in the town of walkerton, ontario, canada in may 2000. the severity of this drinking water disaster resulted in the government of ontario calling a public inquiry by mr. justice dennis o'connor to address the cause of the outbreak, the role (if any) of government policies in contributing to this outbreak and, ultimately, the implications of this experience on the safety of drink ... | 2003 | 12638998 |
drinking water contamination in walkerton, ontario: positive resolutions from a tragic event. | in may 2000, escherichia coli o157:h7 and campylobacter jejuni contaminated the drinking water supply in walkerton, ontario. seven people died and over 2,000 were ill as a result. the ontario provincial government set up a judicial inquiry into the circumstances surrounding the outbreak and also moved quickly to introduce a new drinking water regulation that incorporated some significant requirements for drinking water providers. the inquiry itself was in three parts: (a) part 1 related to the e ... | 2003 | 12638997 |
antimicrobial resistance in campylobacter spp. isolated from ontario sheep flocks and associations between antimicrobial use and antimicrobial resistance. | the objectives of this study were to determine the prevalence of antimicrobial resistance (amr) in faecal campylobacter spp. from lambs and adult sheep and associations between antimicrobial use (amu) and amr. a total of 275 faecal samples collected during initial and final visits from 51 sheep flocks, including one feedlot, across southern ontario were tested for the presence of campylobacter spp. campylobacter jejuni was detected in 52% (143/275) of the faecal samples, campylobacter coli in 7% ... | 2012 | 22273455 |
resistance to quinolones among campylobacter species--ontario. | | 1995 | 7581214 |
outbreak of campylobacter infection among farm workers: an occupational hazard. | | 1995 | 7581213 |
an outbreak of campylobacter jejuni gastroenteritis at a resort--ontario. | | 1988 | 3242891 |
an outbreak of campylobacter jejuni gastroenteritis linked to meltwater contamination of a municipal well. | a large outbreak of campylobacter jujuni gastroenteritis attributed to contamination of an unchlorinated municipal water system was investigated. unlike most previous summer outbreaks, this one began in early spring and was attributed to meltwater entering one or more municipal wells. 241 suspected cases were documented, but retrospective information from local health care workers suggested a much larger outbreak. 45 laboratory-confirmed cases participated in a case-control study which showed a ... | 1991 | 2009481 |
simple and economical culture of campylobacter jejuni and campylobacter coli in co2 in moist air. | strains of campylobacter jejuni and c. coli representing the 18 serogroups (lior) most commonly isolated from humans in canada were grown on solid media in an atmosphere of 10% co2 in moist air, 99% relative humidity. when the growth of all 18 serogroups on mueller hinton agar in a microaerobic atmosphere (5% o2, 10% co2 and 85% n2) was compared with the growth of all 18 serogroups on the same media in 10% co2 in moist air, colony sizes were significantly larger (p less than 0.05) for strains gr ... | 1992 | 1419543 |
factors that led to the walkerton tragedy. | in may 2000, bacterial contamination of municipal water in walkerton, ontario, resulted in the worst public health disaster involving municipal water in canadian history. at least seven people died and 2300 became ill. a public inquiry led by judge dennis o'connor examined the events and delineated the causes of the outbreak, including physical causes, the role of the public utilities operators, the public utilities commissioners, the ministry of the environment (moe), and the provincial governm ... | 2009 | 19180129 |
occurrence of campylobacter spp. in raw and ready-to-eat foods and in a canadian food service operation. | the occurrence of campylobacter spp. in a variety of foods from ottawa, ontario, canada, and raw milk samples from across canada was determined over a 2-year period. the samples consisted of 55 raw foods (chicken, pork, and beef), 126 raw milk samples from raw milk cheese manufacturers, and 135 ready-to-eat foods (meat products, salads, and raw milk cheeses). campylobacter jejuni was detected in 4 of the 316 samples analyzed: 1 raw beef liver sample and 3 raw chicken samples. an isolation rate o ... | 2008 | 18939758 |
arthritis risk after acute bacterial gastroenteritis. | reactive arthritis (rea) may occur from bacterial gastroenteritis. we studied the risk of arthritis after an outbreak of escherichia coli o157:h7 and campylobacter species within a regional drinking water supply to examine the relationship between the severity of acute diarrhoea and subsequent symptoms of arthritis. | 2008 | 18184664 |
association of food premises inspection and disclosure program with retail-acquired foodborne illness and operator noncompliance in toronto. | in 2001, the city of toronto was the only health unit in canada to have implemented a multi-component disclosure system as part of its provincially mandated food safety program. to measure the impact on the ultimate goal of preventing foodborne illness, the authors of the study reported here assessed directly the association of toronto public health's program with the specific incidence of retail-acquired foodborne illness by analyzing secondary data on reportable local enteric disease. in addit ... | 2007 | 17802819 |
prevalence of resistance to 11 antimicrobials among campylobacter coill isolated from pigs on 80 grower-finisher farms in ontario. | we carried out a cross-sectional study to investigate antimicrobial resistance patterns of campylobacter coli isolated from ontario grower-finisher pigs. from january to june 2004, 1200 samples were collected from 80 farms by obtaining a constant number (15) of fecal samples per farm. susceptibility of the isolates to 11 antimicrobial drugs was determined by the agar-dilution technique. the overall prevalence of resistance to 1 or more antimicrobials among the isolates was 99.2%. high levels of ... | 2007 | 17695593 |
prevalence of campylobacter spp isolated from grower-finisher pigs in ontario. | this study aimed to establish the prevalence of campylobacter spp. in 80 ontario grower-finisher pig herds. ninety-nine percent of the isolates yielded campylobacter, c coli being the most common species detected. control of this microorganism must rely on careful food processing and storage of pork, rather than on an on-farm approach. | 2007 | 17542372 |
descriptive epidemiology of enteric illness for selected reportable diseases in ontario, 2003. | | 2006 | 17175595 |
hydrologic modeling of pathogen fate and transport. | a watershed-scale fate and transport model has been developed for escherichia coli and several waterborne pathogens: cryptosporidiumspp., giardiaspp., campylobacter spp, and e. coli o157:h7. the objectives were to determine the primary sources of pathogenic contamination in a watershed used for drinking water supply and to gain a greater understanding of the factors that most influence their survival and transport. to predict the levels of indicator bacteria and pathogens in surface water, an ex ... | 2006 | 16913133 |
incidence and epidemiology of irritable bowel syndrome after a large waterborne outbreak of bacterial dysentery. | postinfectious irritable bowel syndrome (pi-ibs) is a common clinical phenomenon. to better define its incidence and epidemiology, a large cohort study was initiated after the contamination of a municipal water supply led to a large outbreak of acute escherichia coli 0157:h7 and campylobacter jejuni gastroenteritis. | 2006 | 16890598 |
a gradient of acute gastroenteritis was characterized, to assess risk of long-term health sequelae after drinking bacterial-contaminated water. | a municipal water system became contaminated with escherichia coli o157:h7 and campylobacter spp. beginning 2 years after an outbreak, all residents from the region were invited to participate in a cohort study assessing the risk of long-term sequelae. we aimed to develop a method to grade the accuracy and severity of self-reported acute symptoms. | 2006 | 16549265 |
post-infectious irritable bowel syndrome following water contamination. | post-infectious irritable bowel syndrome (pi-ibs) is a common disorder wherein symptoms of ibs begin after an episode of acute gastroenteritis. the walkerton health study (whs) was initiated in 2002 to study the long-term outcomes of tragic contamination of its municipal water supply with escherichia coli and campylobacter species in 2000. within a cohort of 2069 adult walkerton residents with no prior history of chronic gastrointestinal disorders, the incidence of pi-ibs 2 years after the outbr ... | 2009 | 19180133 |
antimicrobial resistance in campylobacter, salmonella, and escherichia coli isolated from retail turkey meat from southern ontario, canada. | this study estimated the prevalence of campylobacter, salmonella, and escherichia coli isolated from fresh retail turkey purchased at grocery stores in ontario, canada. the antimicrobial susceptibility patterns were determined and assessed for potential public health risk. from february 2003 to may 2004, 465 raw turkey meat samples were collected. antimicrobial susceptibility testing was performed for campylobacter isolates with a concentration gradient test and for salmonella and e. coli isolat ... | 2009 | 19343933 |
occurrence of salmonella, campylobacter, yersinia enterocolitica, escherichia coli o157 and listeria monocytogenes in swine. | the objective of this study was to investigate the occurrence of major bacterial foodborne pathogens in swine. in total, 359 samples from manure storage tanks (91) and fresh pooled faeces (268) obtained from finisher (110), sows (78) and weanlings (80) were collected and tested. campylobacter, salmonella, yersinia enterocolitica, escherichia coli o157 and listeria monocytogenes were isolated from 36.5%, 31.5%, 5.8%, 3.3% and 3.3% of samples respectively. all e. coli o157 isolates found on 10 far ... | 2010 | 19638163 |
long-term health sequelae following e. coli and campylobacter contamination of municipal water. population sampling and assessing non-participation biases. | following bacterial contamination of a municipal water system in the rural town of walkerton, ontario, over 2,300 cases of acute gastroenteritis were documented. the walkerton health study is currently underway to assess for long-term health sequelae among consenting inhabitants of walkerton, related to the original outbreak. we explored whether the association between the acute exposure and preliminary long-term health outcomes may have been biased through differences between early- and late-re ... | 2005 | 15850033 |
distribution and diversity of escherichia coli populations in the south nation river drainage basin, eastern ontario, canada. | we investigated the prevalence and diversity of escherichia coli strains isolated from surface waters from multiple watersheds within the south nation river basin in eastern ontario, canada. the basin is composed of mixed but primarily agricultural land uses. from march 2004 to november 2007, a total of 2,004 surface water samples were collected from 24 sampling sites. e. coli densities ranged from undetectable to 1.64 x 10(5) cfu 100 ml(-1) and were correlated with stream order and proximity to ... | 2010 | 20038693 |
prevalence and antimicrobial resistance in campylobacter spp. isolated from retail chicken in two health units in ontario. | campylobacter is an important enteric pathogen of humans and can cause diarrhea, fever, and abdominal pain. campylobacter infections have frequently been associated with the handling and consumption of raw and undercooked poultry. antimicrobial resistance among campylobacter strains is of concern in the treatment of campylobacteriosis in vulnerable populations. a 2-year multidisciplinary study was conducted in the perth and wellington-dufferin-guelph public health units in ontario, canada, to in ... | 2010 | 20615345 |
factors related to campylobacter spp. carriage in client-owned dogs visiting veterinary clinics in a region of ontario, canada. | summaryfrom july 2008 until may 2009, 240 client-owned pet dogs from seven veterinary clinics in the region of waterloo, ontario, canada participated in a study to determine pet-related management factors that may be associated with the presence of campylobacter spp. in dogs. the prevalence of campylobacter spp. carriage in our study population of pet dogs was 22%, with 19% of the dogs positive for c. upsaliensis, and 3% positive for c. jejuni. a significant risk factor from multivariable logist ... | 2011 | 21208515 |
antimicrobial resistance in campylobacter, salmonella, and escherichia coli isolated from retail grain-fed veal meat from southern ontario, canada. | this study estimated the prevalence of salmonella, campylobacter, and escherichia coli isolates in fresh retail grain-fed veal obtained in ontario, canada. the prevalence and antimicrobial resistance patterns were examined for points of public health significance. veal samples (n = 528) were collected from february 2003 through may 2004. twenty-one salmonella isolates were recovered from 18 (4%) of 438 samples and underwent antimicrobial susceptibility testing. resistance to one or more antimicr ... | 2011 | 21819650 |
associations among pathogenic bacteria, parasites, and environmental and land use factors in multiple mixed-use watersheds. | over a five year period (2004-08), 1171 surface water samples were collected from up to 24 sampling locations representing a wide range of stream orders, in a river basin in eastern ontario, canada. water was analyzed for cryptosporidium oocysts and giardia cyst densities, the presence of salmonella enterica subspecies enterica, campylobacter spp., listeria monocytogenes, and escherichia coli o157:h7. the study objective was to explore associations among pathogen densities/occurrence and objecti ... | 2011 | 21889781 |