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[Lawrence London <lfljvenaura@gmail.com>]

https://www.sciencedaily.com/releases/2019/03/190319083915.htm
Food safety: Dung beetles and soil bacteria reduce risk of human pathogens
Date:March 19, 2019Source:British Ecological SocietySummary:Food safety
regulations increasingly pressure growers to remove hedgerows, ponds and
other natural habitats from farms to keep out pathogen-carrying wildlife
and livestock. Yet, this could come at the cost of biodiversity. New
research encourages the presence of dung beetles and soil bacteria at farms
as they naturally suppress E. coli and other harmful pathogens before
spreading to humans. Share:
FULL STORY
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Food safety regulations increasingly pressure growers to remove hedgerows,
ponds and other natural habitats from farms to keep out pathogen-carrying
wildlife and livestock. Yet, this could come at the cost of biodiversity.

New research published today in the *Journal of Applied Ecology* encourages
the presence of dung beetles and soil bacteria at farms as they naturally
suppress *E. coli* and other harmful pathogens before spreading to humans.

Wild and domesticated pig feces have been known to contaminate produce in
the field, leading to foodborne illnesses. Wild, or feral, pigs especially
pose a risk of moving around pathogens as farmers cannot control where or
when these large animals might show up.

Matthew Jones, who led the research as part of his PhD project at
Washington State University, said: "Farmers are more and more concerned
with food safety. If someone gets sick from produce traced back to a
particular farm it can be devastating for them."

"As a result, many remove natural habitats from their farm fields to
discourage visits by livestock or wildlife, making the farmland less
hospitable to pollinators and other beneficial insects or birds," he added.

Dung beetles bury feces below ground and make it difficult for pathogens to
survive. To study how this may aid food safety, the entomologist drove a
van full of pig faeces along the US West Coast to follow the planting of
broccoli at 70 farm fields during the growing season. Broccoli, much like
leafy greens, is susceptible to fecal contamination due to its proximity to
the ground and the likelihood of humans consuming it without cooking.

The pig faeces were used to attract dung beetles and see how quickly they
would clean up. The experiment was carried out at conventional and organic
farms, and farms with or without livestock.

The organic farms seemed to attract a diverse range of dung beetle species
that were most effective at keeping foodborne pathogens at bay. At
conventional fields or those surrounded by pastureland, a less effective
and accidentally introduced species (*Onthophagus nuchicornis*) outweighed
the number of native dung beetles.

"We found that organic farms generally fostered dung beetle species that
removed the feces more rapidly than was seen on conventional farms," said
Professor William Snyder of Washington State University.

Dung beetles likely kill harmful bacteria when they consume and bury the
feces. Previous research also suggested that these beetles have
antibiotic-like compounds on their body.

To validate these findings, the researchers exposed the three most common
species found in the field survey to pig feces contaminated with *E. coli*.
A 7-day laboratory experiment revealed that *Onthophagus taurus* and
*Onthophagus
nuchicornis*, both of which bury faeces as part of their breeding
behaviour, reduced *E. coli* numbers by > 90% and < 50% respectively.

They also found that organic farming encouraged higher biodiversity among
soil bacteria, which decreased the survival of pathogens.

"Bacteria are known to poison and otherwise fight among themselves and the
same may be happening here," said Snyder.

These results suggest dung beetles and soil bacteria may improve the
natural suppression of human pathogens on farms, making a case for reduced
insecticide use and the promotion of greater plant and insect diversity.

"Wildlife and livestock are often seen as something that endanger food
safety, but our research shows that reducing on-farm biodiversity might be
totally counterproductive," Jones concluded.

"Nature has a 'clean-up crew' of dung beetles and bacteria that quickly
remove feces and the pathogens within them, it appears. So, it might be
better to encourage these beneficial insects and microbes."
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*Story Source:*

Materials
<https://www.britishecologicalsociety.org/food-safety-dung-beetles/>
provided by *British Ecological Society*
<https://www.britishecologicalsociety.org/>. Original written by Sabrina
Weiss. *Note: Content may be edited for style and length.*
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*Journal Reference*:

   1. Jones MS, Fu Z, Reganold JP, et al. *Organic farming promotes biotic
   resistance to foodborne human pathogens*. *J Appl Ecol.*, 2019 DOI:
   10.1111/1365-2664.13365 <http://dx.doi.org/10.1111/1365-2664.13365>

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-- 
Lawrence F. London, Jr.
lfljvenaura@gmail.com
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