¶ … Food Safety Hazards of Livestock
Centers for Disease Control and Prevention (CDC) tracks ongoing Eschericia coli outbreaks across the nation, including those arising from leafy green vegetables. For example, in 2012, 58 people were sickened by an E. coli O157:H7 outbreak in the Midwest that was eventually tracked to a Missouri farm producing romaine lettuce (CDC). In 2006, close to 200 people became ill when exposed to O157:H7-contaminated baby spinach harvested from the Central Valley of California (Warnert). The 2006 outbreak resulted in the death of two elderly women and a 2-year-old boy. Making matters worse, nearly 80% of the nation's leafy greens are grown in the Central Valley. Needless to say, the impact on public trust concerning the safety of farm produce was considerable.
The U.S. Food and Drug Administration (FDA) also tracked the behavior of consumers following the 2006 outbreak (Arnade, Calvin, and Kuchler 734). What was unique about this outbreak was the FDA was warning the public as the outbreak was occurring, for nearly two weeks, whereas in the past the FDA was typically was behind the curve and notifying the public after the outbreaks had already ceased. Consumers in 26 states and a Canadian province became ill, requiring 104 hospitalizations. As a result of the media coverage nearly 87% of consumers were aware of the outbreak as it was occurring. By week 3 following the FDA announcement, bagged spinach sales had bottomed out at 63% of normal sales and was still 10% below predicted sales levels by week 68 (744). Bulk spinach bottomed out one week after the FDA announcement at 32% below expected sales volumes, but had recovered by week 26. During this shock to the spinach...
coli spinach contamination was increased research into the sources of contamination and changes in farming procedures. The U.S. Department of Agriculture (USDA) and California
university researchers investigated the source of 2006 outbreaks using the latest biotechnology tools (Warnert). Once the contaminated spinach field had been located, researchers first identified O157:H7 in cattle feces about a mile from the field (Jay et al. 1908). During this
investigation, feral swine were observed in the area and an effort was begun to trap and test local wildlife, in addition to all forms of local livestock,
pets, sources of water, and soil. The O157:H7 strain was detected in cattle and feral swine feces, in addition to
water and soil samples (Jay et al. 1909). Although the contaminated spinach field was fenced to prevent cattle from entering the researchers found evidence for wildlife intrusion, including the presence of feral swine tracks.
The ultimate source of the O157:H7 strain was believed to cattle, which transmitted the
bacteria to the feral swine through contaminated ground water (Benjamin et al. 81-82). In order to quantify the
risk cattle pose to fields of leafy green vegetables researchers surveyed coastal ranches in California for O157 contamination of livestock, water sources, and soil. O157 was detected in 2.6% of cattle fecal matter, 1.5% of water sources, and 1.1% of soil samples on 8 cattle ranches, although there was high variability in contamination levels between ranches (84-85). For example, 44 of 49 cattle tested on a single ranch on one date tested positive for O157-contaminate fecal…
