[USCC] Fwd: "Scientists to Begin Looking for Sources of E. coli in California's Salinas Valley"

[Jim McNelly]

>
>*   "Scientists to Begin Looking for Sources of E. coli in 
>California's Salinas Valley" is the title of an October 16 news 
>release issued by the University of California which states in part 
>that " ... Before the year's end, a team of scientists will begin 
>collecting data for a long-planned four-year study on the sources of 
>E. coli O157:H7 in the Salinas Valley. The study is funded with a 
>$1.2 million research grant from the USDA. 'Exactly where the E. 
>coli is coming from is a focus of the grant,' said Edward (Rob) 
>Atwill, a UC Davis School of Veterinary Medicine specialist in 
>waterborne infectious diseases and co-principal investigator of the 
>study. 'There has been much speculation that livestock or wildlife 
>are possible sources of the E. coli O157:H7 in these outbreaks in 
>fresh produce from Salinas Valley region. We will examine livestock 
>and wildlife that are out on the rangeland up above the farmland, 
>and wildlife that live near canals and on the periphery of vegetable 
>fields on the valley floor.' In the first two years of the study, 
>crews will collect thousands of samples of domestic animal and 
>wildlife droppings; creek, ditch and irrigation water; farm soil and 
>lettuce growing on Salinas Valley farms. (This study was designed 
>before the late summer 2006 outbreak of E. coli O157:H7 associated 
>with spinach. Several previous outbreaks of the virulent bacteria 
>were associated with contaminated Salinas Valley lettuce.) The data 
>collected in the field will be carefully analyzed to identify the 
>vertebrates that are sources of E. coli O157:H7, assess the climate, 
>landscape attributes and irrigation management practices that are 
>correlated with increased risk of contamination, and determine 
>whether contaminated lettuce is associated with certain farming 
>practices or environmental factors ... 'We need to deal with facts,' 
>said Robert Mandrell, research leader of the USDA-Agricultural 
>Research Service Produce Safety and Microbiology Research Unit and 
>the principle investigator of the study. 'Right now, we can't say 
>what's happening. We will get facts that will give us a basis to 
>determine what more we need to investigate.' The scientists hope 
>their research will also help them understand the puzzling timing of 
>recent E. coli outbreaks. E. coli bacteria are found more often in 
>Salinas Valley waterways in the winter, when rainstorms can wash the 
>bacteria from streets, farms, and rangeland into creeks, streams, 
>sloughs and rivers. However, the outbreaks associated with fresh 
>vegetables tend to happen during the summer and fall ... The 
>information from Mandrell, Atwill and their colleagues' E. coli 
>study will be used to inform growers about specific strategies they 
>can use to prevent contamination of vegetables in the field, to 
>educate the public about the potential impacts of rangeland runoff, 
>and to develop effective management practices for improving water 
>quality ..." - The compete text of the news release is posted at 
><http://news.ucanr.org/newsstorymain.cfm?story=872>http://news.ucanr.org/newsstorymain.cfm?story=872 
>and 
><http://newswire.ascribe.org/cgi-bin/behold.pl?ascribeid=20061016.135224&time=15%2025%20PDT&year=2006&public=0>http://newswire.ascribe.org/cgi-bin/behold.pl?ascribeid=20061016.135224&time=15%2025%20PDT&year=2006&public=0 
>- Researchers Atwill may be reached at 530 754 2154; e-mail: 
><mailto:RAtwill at vmtrc.ucdavis.edu>RAtwill at vmtrc.ucdavis.edu and 
>Mandrell at 510 559 6165; e-mail: 
><mailto:Mandrell at pw.usda.gov>Mandrell at pw.usda.gov
>
>http://news.ucanr.org/newsstorymain.cfm?story=872
>http://newswire.ascribe.org/cgi-bin/behold.pl?ascribeid=20061016.135224&time=15%2025%20PDT&year=2006&public=0
>
>Mon Oct 16 15:25:45 2006 Pacific Time
>
>Scientists to Begin Looking for Sources of E. coli in California's 
>Salinas Valley
>
>OAKLAND, Calif., Oct. 16 (AScribe Newswire) -- Before the year's 
>end, a team of scientists will begin collecting data for a 
>long-planned four-year study on the sources of E. coli O157:H7 in 
>the Salinas Valley. The study is funded with a $1.2 million research 
>grant from the USDA.
>
>        "Exactly where the E. coli is coming from is a focus of the 
> grant," said Edward (Rob) Atwill, a UC Davis School of Veterinary 
> Medicine specialist in waterborne infectious diseases and 
> co-principal investigator of the study. "There has been much 
> speculation that livestock or wildlife are possible sources of the 
> E. coli O157:H7 in these outbreaks in fresh produce from Salinas 
> Valley region. We will examine livestock and wildlife that are out 
> on the rangeland up above the farmland, and wildlife that live near 
> canals and on the periphery of vegetable fields on the valley floor."
>
>        In the first two years of the study, crews will collect 
> thousands of samples of domestic animal and wildlife droppings; 
> creek, ditch and irrigation water; farm soil and lettuce growing on 
> Salinas Valley farms. (This study was designed before the late 
> summer 2006 outbreak of E. coli O157:H7 associated with spinach. 
> Several previous outbreaks of the virulent bacteria were associated 
> with contaminated Salinas Valley lettuce.)
>
>        The data collected in the field will be carefully analyzed 
> to identify the vertebrates that are sources of E. coli O157:H7, 
> assess the climate, landscape attributes and irrigation management 
> practices that are correlated with increased risk of contamination, 
> and determine whether contaminated lettuce is associated with 
> certain farming practices or environmental factors.
>
>        "We need to deal with facts," said Robert Mandrell, research 
> leader of the USDA-Agricultural Research Service Produce Safety and 
> Microbiology Research Unit and the principle investigator of the 
> study. "Right now, we can't say what's happening. We will get facts 
> that will give us a basis to determine what more we need to investigate."
>
>        Facts will come also from the use of sophisticated tests 
> called MultiLocus Variable tandem repeat Analysis (MLVA) and Pulsed 
> Field Gel Electrophoresis (PFGE) to "fingerprint" and track 
> bacteria found in various animals, waterways, farms and vegetables. 
> PFGE is the same process used by the Centers for Disease Control to 
> discover whether food-borne disease outbreaks are related to one 
> another, as was found to be the case with spinach in September 
> 2006, and MLVA is a recent method for assessing the relatedness of 
> strains isolated.
>
>        "Most strains of E. coli O157:H7 bacteria are so similar, we 
> need to look at the genome to accurately trace the source through 
> the environment," Mandrell said.
>
>        The scientists hope their research will also help them 
> understand the puzzling timing of recent E. coli outbreaks. E. coli 
> bacteria are found more often in Salinas Valley waterways in the 
> winter, when rainstorms can wash the bacteria from streets, farms, 
> and rangeland into creeks, streams, sloughs and rivers. However, 
> the outbreaks associated with fresh vegetables tend to happen 
> during the summer and fall.
>
>        "Is there a hydrological link between what is occurring on 
> rangeland above the fields and the E. coli contaminated vegetables 
> that are reported in the summer and fall? That's what we are going 
> to test," Atwill said.
>
>        Certain strains of E. coli bacteria normally live in the 
> intestines of cattle, wildlife and humans causing no harm. The 
> O157:H7 strain became known in 1982 as a result of an outbreak 
> associated with hamburger meat. It causes severe diarrhea and can 
> lead to kidney damage and even death. Young children and the 
> elderly are particularly vulnerable. However, some humans with E. 
> coli O157:H7 show no symptoms at all.
>
>        "There's a lot we don't know about why certain people don't 
> get sick," Mandrell said. "Are certain strains more virulent? The 
> particular strain in the spinach outbreak seems to be particularly virulent."
>
>        Compared to other strains of E. coli, the O157:H7 strain is 
> unusually persistent in the environment. It survives in low 
> temperatures, such as cold water and under refrigeration. Heat, in 
> the pasteurization of milk and fruit juices or in cooking, destroys 
> E. coli bacteria. E. coli on the outer surfaces of cuts of meat are 
> easily destroyed during cooking. But E. coli in ground meat may be 
> deep within the hamburger. Cooked hamburgers with pink meat in the 
> middle can still have live E. coli O157:H7 cells.
>
>        Cooking vegetables also destroys bacteria, but contaminated 
> vegetables meant to be eaten raw pose the problem. Washing rarely 
> completely cleans all the bacteria off and very little bacteria can 
> make a person ill. It is thought that only 10 to 100 bacteria can 
> cause disease in humans; a large animal with E. coli O157:H7, such 
> as a cow, sometimes can shed millions of bacteria per gram of feces.
>
>        The information from Mandrell, Atwill and their colleagues' 
> E. coli study will be used to inform growers about specific 
> strategies they can use to prevent contamination of vegetables in 
> the field, to educate the public about the potential impacts of 
> rangeland runoff, and to develop effective management practices for 
> improving water quality.
>
>        The scientists involved in the study are Mandrell; Atwill; 
> Michael Cooley, microbiologist, USDA-ARS-WRRC-PSMRU; Ken Tate, UC 
> Cooperative Extension rangeland watershed specialist, UC Davis 
> Department of Plant Sciences; Royce Larsen, UC Cooperative 
> Extension area natural resource watershed advisor, San Luis Obispo 
> County; Leta Crawford-Miksza, Chief, Food Microbiology Section, 
> Food and Drug Laboratory Branch, California Department of Health 
> Services; Janet Mohle-Boetani, Chief, Disease Investigations 
> Section, Infectious Diseases Branch, California Department of 
> Health Services; and Michelle Jay-Russell, Western Institute for 
> Food Safety and Security, UC Davis and California Department of 
> Health Services.
>
>        - - - -
>
>CONTACTS:
>
>Edward "Rob" Atwill, 530-754-2154, ratwill at vmtrc.ucdavis.edu
>
>Robert Mandrell, 510-559-6165, mandrell at pw.usda.gov
>
>Jeannette Warnert, UC Ag & Natural Resources Public Information, 
>jwarnert at ucop.edu, 559-241-7514
>
>ON THE WEB: A site for news media - http://news.ucanr.org
>
>       Media Contact: See above.
>
>end
>
>
>
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>
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