Wild Farm Alliance
Wild Farm Alliance
Wild Farm Alliance             About       What is Wild Farming        Resources        News        Contact        Support
Wild Farm Alliance
Wild Farm Alliance

Food Safety Teach-In
Food Safety in the News
Habitat Destruction
Industrial-Sized Problems

Press Room

Latest Research Findings and Background

Relative Risk of Animals in Produce Fields

Food Safety Requires a Healthy Environment

Food Safety vs. Environment: Actual or Perceived Conflict?

E. coli O157: A Biography

Animals and Food Safety
CA Wildlife in General

Deer

Rodents
Feral Swine
Cattle

Vegetation as Pathogen Filter

Food Safety Requires a Healthy Environment

WFA Food Safety Paper "Food Safety Requires a Healthy Environment: Policy Recommendations for E. coli O157"
In the paper, a set of recommendations is made for all current and future government-sanctioned food safety programs. Some are suggested changes to Good Agricultural Practice metrics, and others are changes to the scope of what food safety programs cover. Additionally, suggestions address wider-reaching core problems that when dealt with concurrently, yield a more comprehensive plan for the safe production of food.

Major recommendations include: a) the unfounded targeting of wildlife is stopped; b) buffers between crops and grazing lands are vegetated instead of left bare, and no buffer is required between crops and habitat; c) a ceiling is placed on all government authorized food safety programs to curtail the use of environmentally destructive super metrics; and d) food safety auditors are certified through programs teaching agricultural natural resource protections that reduce the incidence of harmful pathogens on the landscape.

Food Safety vs. Environment: Actual or Perceived Conflict?

Food Safety versus Environmental Protection on the Central California Coast: Exploring the Science Behind an Apparent Conflict
This research brief examines the way that pressures on growers to achieve both food safety and environmental protection are connected--and may be on a collision course. Growers who have recently adopted practices to minimize water pollution may now face pressure to eliminate these conservation measures in order to meet industry guidelines that call for "clean" fields in the name of food safety; such guidelines aim to minimize the presence of wildlife, seen as a potential disease vector. The paper goes on to discuss the ways that food safety guidelines conflict with environmental protection methods, and propose the idea that such methods could in fact reduce contamination sources and improve food safety.
Read Research Brief #10 from the Center for Agroecology and Sustainable Food Systems at UC Santa Cruz.

E. coli O157: A Biography

Published Research on the Sources and Spread of E. coli O157
The Organic Center has posted a set of Frequently Asked Questions (FAQs) to help interested individuals and the media better understand where E. coli O157 comes from, how it can get into food, and what can be done to prevent future human illnesses. The corresponding "Critical Issue Report" provides a roadmap to published research, and teams of scientists conducting cutting edge work to better understand E. coli epidemiology. The report also includes a full bibliography.

Go to FAQs

Unfinished Business: Preventing E. coli O157 Outbreaks in Leafy Greens
Despite the national press attention given to the E. coli outbreak in the fall of 2006, it accounted for less than one-half of one percent of the 52,000 illnesses expected in 2006 from all sources of exposure to E. coli O157. The problem of food-borne illnesses is larger in scope than most people realize, and successfully reducing episodes of produce contamination will depend on a systematic approach that includes reducing pathogen loads at their source, improved methods of testing and information dissemination, and identifying high-risk circumstances and the best measures for dealing with potential problems.

View report

Animals and Food Safety

California Wildlife in General:
Preliminary research compiling two years of data examing 866 individuals showed that one half of one percent carried E.coli O157.

Deer:
Escherichia coli O157:H7 in free-ranging deer in Nebraska
Abstract- In order to determine the prevalence and distribution of the human pathogen, Escherichia coli O157:H7, in free-ranging deer, hunters were asked to collect and submit fecal samples from deer harvested during a regular firearm season (14-22 November 1998). Prior to the season, 47% of the hunters with permits in the southeastern Nebraska (USA) study area indicated a willingness to participate in the study. Approximately 25% of successful hunters in the area submitted deer fecal samples. Escherichia coli O157:H7 was cultured from four (0.25%) of 1,608 total samples submitted. All of the fecal samples that were properly identified (1,426) and all that were positive for E. coli O157:H7 were from white-tailed deer (Odocoileus virginianus). We were unable to detect a statistically significant geographic distribution pattern of E. coli O157:H7. The presence of E. coli O157:H7 in the feces of free-ranging deer has implications not only for hunters, consumers of venison, and others in contact with deer or deer feces, but also for the development of strategies aimed at reducing and/or controlling this pathogen in water sources and domestic livestock.

Go to article

Prevalence of Escherichia coli O157:H7 in White-tailed Deer from Louisiana
ABSTRACT- Escherichia coli O157:H7 (EC O157) is an important zoonosis. White-tailed deer (Odocoileus virginianus) have been implicated in transmission of this bacterium to humans and have been suggested as reservoirs that might affect carriage in cattle populations. Our study objectives were to estimate prevalence of EC O157 in feces of hunter-harvested deer and to describe fecal shedding patterns in a captive herd sampled over 1 yr. Prevalence of EC O157 in hunter-harvested deer was 0.3% (n=338). In August 2001, EC O157 was detected in one of 55 deer (1.8%) from the captive herd. Prevalence over the 1-yr period was 0.4% (n=226). Escherichia coli O157:H7 was rarely isolated from hunter-harvested deer during the winter. We could not describe a seasonal shedding pattern based on one positive sample in the captive herd. These data do not support a prominent role of deer as a reservoir for EC O157 for cattle or humans.

Go to article

Prevalence of Escherichia coli O157:H7 in White-tailed Deer Sharing Rangeland with Cattle
Abstract- To determine the prevalence of fecal shedding of Escherichia coli O157:H7 in white-tailed deer (Odocoileus virginianus) with access to cattle pastures. DESIGN: Survey study. Sample Population: 212 fecal samples from free ranging white-tailed deer. Procedure: Fresh feces were collected on multiple pastures from 2 farms in north central Kansas between September 1997 and April 1998. Escherichia coli O157:H7 was identified by bacterial culture and DNA-based methods. Results: Escherichia coli O157:H7 was identified in 2.4% (5/212) of white-tailed deer fecal samples. Conclusions and Clinical Relevance: There is considerable interest in the beef industry in on-farm control of E coli O157:H7 to reduce the risk of this pathogen entering the human food chain. Results of our study suggest that the design of programs for E coli O157:H7 control in domestic livestock on pasture will need to account for fecal shedding in free-ranging deer. In addition, the results have implications for hunters, people consuming venison, and deer-farming enterprises.

Go to article

Experimental and Field Studies of Escherichia coli O157:H7 in White-tailed Deer
Studies were conducted to evaluate fecal shedding of Escherichia coli O157:H7 in a small group of inoculated deer, determine the prevalence of the bacterium in free-ranging white-tailed deer, and elucidate relationships between E. coli O157:H7 in wild deer and domestic cattle at the same site. Six young, white-tailed deer were orally administered 10(8) CFU of E. coli O157:H7. Inoculated deer were shedding E. coli O157:H7 by 1 day postinoculation (DPI) and continued to shed decreasing numbers of the bacteria throughout the 26-day trial. Horizontal transmission to an uninoculated deer was demonstrated. Although E. coli O157:H7 bacteria were recovered from the gastrointestinal tracts of deer necropsied from 4 to 26 DPI, attaching and effacing lesions were not apparent in any deer. Results are similar to those of inoculation studies in calves and sheep. In field studies, E. coli O157 was not detected in 310 fresh deer fecal samples collected from the ground. It was detected in feces, but not in meat, from 3 of 469 free-ranging deer in 1997. In 1998, E. coli O157 was not detected in 140 deer at the single positive site found in 1997; however, it was recovered from 13 of 305 dairy and beef cattle at the same location. Isolates of E. coli O157:H7 from deer and cattle at this site differed with respect to pulsed-field gel electrophoresis patterns and genes encoding Shiga toxins. The low overall prevalence of E. coli O157:H7 and the identification of only one site with positive deer suggest that wild deer are not a major reservoir of E. coli O157:H7 in the southeastern United States. However, there may be individual locations where deer sporadically harbor the bacterium, and venison should be handled with the same precautions recommended for beef, pork, and poultry.

Go to article

Rodents:
Crop Notes
from Monterey County's Cooperative Extension
"Since the outbreak of E. coli O157:H7 on spinach from California's central coast in September, 2006 there have been a number of measures proposed and implemented to help reduce the risk of microbial contamination in leafy green vegetables. Unfortunately, there is a lack of science based information supporting many of these practices. The presumed role of animals in the microbial contamination outbreaks has caused companies to require growers to exclude animals from fields. As a result, there have been efforts made to control rodents and other species by using traps, baits, and fences."

Terry Salmon, Extension Vertebrate Pest Specialist, discussed the unlikelihood of rodents as vectors of E. coli O157:H7. "To our knowledge, voles, mice, ground squirrels, and other rodents in coastal California agricultural fields have not been found to harbor pathogenic E. coli...it appears unlikely that these rodents will be found to be a common or important source of O157:H7 and other pathogenic strains."

Go to article

Feral Swine:
E. coli O157:H7 in Feral Swine near Spinach Fields and Cattle, Central California Coast
Abstract- We investigated involvement of feral swine in contamination of agricultural fields and surface waterways with Escherichia coli O157:H7 after a nationwide outbreak traced to bagged spinach from California. Isolates from feral swine, cattle, surface water, sediment, and soil at one ranch were matched to the outbreak strain.

Go to article

Cattle:
Prevalence and Pathogenicity of Shiga toxin-producing Esherichia coli in Beef Cattle and their Products
Abstract- During the past 23 years, a large number of human illness outbreaks have been traced worldwide to consumption of undercooked ground beef and other beef products contaminated with Shiga toxin-producing Escherichia coli (STEC). Although several routes exist for human infection with STEC, beef remains a main source. Thus, beef cattle are considered reservoirs of O157 and non-O157 STEC.

Go to article

Grain Feeding and the Dissemination of Acid-Resistant Escherichia coli from Cattle
Abstract- The gastric stomach of humans is a barrier to food-borne pathogens, but Escherichia coli can survive at pH 2.0 if it is grown under mildly acidic conditions. Cattle are a natural reservoir for pathogenic E. coli, and cattle fed mostly grain had lower colonic pH and more acid-resistant E. coli than cattle fed only hay. On the basis of numbers and survival after acid shock, cattle that were fed grain had 106-fold more acid-resistant E. coli than cattle fed hay, but a brief period of hay feeding decreased the acid-resistant count substantially.

Go to article

Scientists Study Possible Link between Ethanol Byproduct and E. coli
Abstract- A nationwide surge in beef recalls has pointed the finger at an unlikely culprit - the nation’s fuel ethanol industry. Studies at two universities suggest that feeding cattle a byproduct of ethanol production known as distillers grains may increase levels of a deadly form of E. coli bacteria.

Go to article

Vegetation as Pathogen Filter

Significant Escherichia coli Attenuation by Vegetative Buffers on Annual Grasslands
Abstract- A study was conducted to estimate the retention efficiency of vegetative buffers for Escherichia coli deposited on grasslands in cattle fecal deposits and subject to natural rainfall-runoff conditions. Approximately 94.8 to 99.995% of total E. coli load applied to each plot appears to be either retained in the fecal pat and/or attenuated within 0.1 m downslope of the fecal pat, irrespective of the presence of a wider vegetated buffer. Relative to a 0.1-m buffer, we found 0.3 to 3.1 log10 reduction in E. coli discharge per additional meter of vegetative buffer across the range of residual dry vegetation matter levels, land slope, and rainfall and runoff conditions experienced during this project. Buffer efficiency was significantly reduced as runoff increased. These results support the assertion that grassland buffers are an effective method for reducing animal agricultural inputs of waterborne E. coli into surface waters.

Go to article

Management Reduces E. coli in Irrigated Pasture Runoff
Abstract- Microbial pollutants, some of which can cause illnesses in humans, chronically contaminate many California water bodies. Among numerous sources, runoff from irrigated pastures has been identified as an important regulatory target for improving water quality. This study examined the potential to reduce E. coli contamination from cattle in irrigated pastures. During the 14 irrigation events examined, we found that E. coli concentrations were lowest with a combination of three treatments: filtering runoff through a natural wetland, reducing runoff rates, and letting the pasture rest from grazing at least a week prior to irrigation. Integrated pasture and tailwater management are required to significantly reduce E. coli concentrations in runoff.

Go to article

© 2008 Wild Farm Alliance. All Rights Reserved.