HERE

Clean Greens Demand Tough to Meet



2007 September -   The rise in year-round 
consumption of fresh leafy greens such as lettuce and baby spinach is 
making it more difficult to keep produce free from contamination by food 
poisoning bacteria, said a U.S. scientist Monday at the Society for 
General Microbiology’s conference at the University of Edinburgh. 
“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,” said Robert Mandrell from the U.S. 
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,” said Mandrell, who is research leader in 
the produce safety and microbiology research unit in Albany. 
Following media coverage of outbreaks caused by E. coli in leafy 
vegetables and salmonella in tomatoes, the U.S. fresh produce industry and 
federal and state agencies are trying to address the microbial food safety 
of leafy greens and other vegetables. 
Major U.S. produce industry associations have worked together to establish 
a marketing agreement, a set of food safety guidelines 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, Mandrell said. 
Logical theories about pre-harvest contamination provide points for study, 
but Mandrell could provide no definitive conclusions about the most recent 
outbreaks. Fresh, minimally processed leafy greens are here to stay, he 
said, if the industry continues to work hard to re-establish consumer 
confidence. 

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