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Bacteriophages are showing promise as a way to control E.
coli on lettuce and fresh cantaloupe. Photo courtesy of Microsoft
clipart.
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Antimicrobials Target Produce Pathogens
By
Rosalie Marion Bliss
July 16 , 2008
A novel food safety treatment tested by
Agricultural Research Service (ARS)
scientists could become an asset to the fast-growing fresh-cut produce
industry.
The antimicrobial treatment involves the use of submicroscopic agents
that are unable to reproduce or grow outside bacterial host cells. The purified
viral agents are called bacteriophages, which means "bacteria eater," and they
can wreak havoc on deadly bacteria, such as E. coli O157:H7, that sicken
consumers.
The bacteriophage research is being conducted by microbiologist
Manan
Sharma, with the ARS
Food
Safety Laboratory, in Beltsville, Md., in collaboration with researchers at
Intralytix, Inc., based in Baltimore,
Md.
Interest in bacteriophages is ramping up with the emergence of
antibiotic-resistant organisms. These "phages" are present in the environment
and only attack bacteria; they do not have an adverse effect on humans and
animals.
Sharma tested a group of phages (ECP-100) on refrigerated samples of
fresh-cut cantaloupe. The treatments reduced pathogens on the samples of
fresh-cut cantaloupe by 100-fold in comparison to untreated samples.
Sharma also tested the phages on refrigerated fresh-cut lettuce. The
results indicate that bacteriophage treatments can kill E. coli O157:H7 on the
surface of leafy green commodities with the same level of efficiency seen in
the fresh-cut cantaloupe.
Phages reproduce by latching onto bacteria. The viral DNA is injected
into the bacterial hosts' cells, where it directs the production of progeny
phages. These phages kill bacterial host cells on exit, and then move on to
infect more bacterial cells.
The trials indicated that the phage treatments could be effective in
killing E. coli O157:H7 in produce.
Read more about the research in the
July 2008
issue of Agricultural Research magazine.
ARS is a scientific research agency of the
U.S. Department of Agriculture.