Reading, United Kingdom
August 28, 2007
The rise in year-round consumption
of fresh leafy greens such as lettuce and baby spinach is
increasing the difficulty of keeping produce free from
contamination by food poisoning bacteria, according to US
scientists speaking today (Monday 3 September 2007) at the
Society for General Microbiology’s
161st Meeting at the University of Edinburgh, UK, which runs
from 3-6 September 2007.
“The only land suitable for supplying this abundance of
year-round, high quality, fresh leafy vegetables, which are
eaten raw by large populations in Europe and the United States,
is in special geographic regions, with ideal soil and climate
conditions”, says Robert
Mandrell from the US Department of Agriculture’s Research
Service in Albany, California.
This move to the year-round supply of leafy vegetables has
required new methods to clean, package and deliver rapidly these
fragile food items across large distances to consumers in many
parts of the world. These include harvesting mowers for some
leafy greens, processing in water flumes and triple washing, and
modified atmosphere packaging for extended shelf-life.
Recent food scares and food poisoning outbreaks have led to
intensive investigations of farms and ranches. These have shown
that at least some food poisoning bacteria outbreaks have been
due to field contamination before the greens are even harvested.
“This situation complicates strategies for eliminating illnesses
and outbreaks due to the complex ecosystem of multiple potential
sources, such as water, wildlife, and nearby livestock, all of
which could be sources of bacteria causing food poisoning”, says
Robert Mandrell.
Following wide media coverage of outbreaks caused by E. coli in
leafy vegetables and Salmonella in tomatoes, the US fresh
produce industry and federal and state agencies are trying to
address the microbial food safety of leafy greens and other
vegetables. Major US produce industry associations have worked
together to establish a marketing agreement, a set of food
safety guidelines (metrics) for growers to produce and harvest
leafy greens, and have increased funding for research.
Probably, a convergence of unusual events is required for very
large outbreaks to occur, a factor everyone is hoping will not
affect 2007 harvests. Logical theories about pre-harvest
contamination provide points for study, but no definitive
conclusions about the most recent outbreaks can be provided.
Fresh, minimally processed leafy greens are here to stay, if the
industry continues to work hard to re-establish consumer
confidence.
Dr Mandrell is presenting the paper ‘Fresh leafy greens and
Escherichia coli O157:H7: outbreaks, incidence in the
environment, source-tracking’ at 0945 on Monday 03 September
2007 in the Microbial Infection Group session of the 161st
Meeting of the Society for General Microbiology at the
University of Edinburgh, 3-6 September 2007.
Full programme details of this meeting can be found on the
Society's website at:
http://www.sgm.ac.uk/meetings/MTGPAGES/Edinburgh07.cfm. Hard
copies are available on request from the SGM.
The Society for General Microbiology is the largest microbiology
society in Europe, and has over 5,500 members worldwide. The
Society provides a common meeting ground for scientists working
in research and in fields with applications in microbiology
including medicine, veterinary medicine, pharmaceuticals,
industry, agriculture, food, the environment and education.
The SGM represents the science and profession of microbiology to
government, the media and the general public; supporting
microbiology education at all levels; and encouraging careers in
microbiology. |
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