[MCN] Gardens, fresh veggies, and a mistake in food safety policy

[Lance Olsen]

Proceedings of the National Academy of Sciences 
Published online before print August 10, 2015
doi: 10.1073/pnas.1508435112

Comanaging fresh produce for nature conservation and food safety
Daniel S. Karpa, Sasha Gennet et al

agriculture - biodiversity - disease ecology - E. coli  - foodborne pathogens

Significance
Fresh produce has become the primary cause of foodborne illness in 
the United States. A widespread concern that wildlife vector 
foodborne pathogens onto fresh produce fields has led to strong 
pressure on farmers to clear noncrop vegetation surrounding their 
farm fields. We combined three large datasets to demonstrate that 
pathogen prevalence in fresh produce is rapidly increasing, that 
pathogens are more common on farms closer to land suitable for 
livestock grazing, and that vegetation clearing is associated with 
increased pathogen prevalence over time. These findings contradict 
widespread food safety reforms that champion vegetation clearing as a 
pathogen mitigation strategy. More generally, our work indicates that 
achieving food safety and nature conservation goals in 
produce-growing landscapes is possible.

Abstract
http://www.pnas.org/content/early/2015/08/05/1508435112.abstract
In 2006, a deadly Escherichia coli O157:H7 outbreak in bagged spinach 
was traced to California's Central Coast region, where >70% of the 
salad vegetables sold in the United States are produced. Although no 
definitive cause for the outbreak could be determined, wildlife was 
implicated as a disease vector. Growers were subsequently pressured 
to minimize the intrusion of wildlife onto their farm fields by 
removing surrounding noncrop vegetation. How vegetation removal 
actually affects foodborne pathogens remains unknown, however. We 
combined a fine-scale land use map with three datasets comprising 
250,000 enterohemorrhagic E. coli (EHEC), generic E. coli, and 
Salmonella tests in produce, irrigation water, and rodents to 
quantify whether seminatural vegetation surrounding farmland is 
associated with foodborne pathogen prevalence in California's Central 
Coast region. We found that EHEC in fresh produce increased by more 
than an order of magnitude from 2007 to 2013, despite extensive 
vegetation clearing at farm field margins. Furthermore, although EHEC 
prevalence in produce was highest on farms near areas suitable for 
livestock grazing, we found no evidence of increased EHEC, generic E. 
coli, or Salmonella near nongrazed, seminatural areas. Rather, 
pathogen prevalence increased the most on farms where noncrop 
vegetation was removed, calling into question reforms that promote 
vegetation removal to improve food safety. These results suggest a 
path forward for comanaging fresh produce farms for food safety and 
environmental quality, as federal food safety reforms spread across 
4.5 M acres of US farmland.


-- 
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"The tendency for success to breed complacency and recklessness is as 
ingrained in financial markets as it is in any other walk of life."

Banks : Barbarians at the vault. The Economist, May 15, 2008
-------------------------------------------------------------------------------------------------------------
  "Access to more capital makes bigger crises feasible: every now and 
then, somewhere in the world, one is going to happen.

"Is this because the same mistakes are made again and again, or is 
each crisis unique?  The answer is yes to both :  each crisis is 
unique, and the same mistakes are made again and again."

"While a bubble is inflating, reckless lending seems merely bold, and 
appropriately well-rewarded."

The Economist, "A cruel sea of capital : A survey of global finance," 
May 3rd, 2003.


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