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【medical-news】联合应用各种技术来对抗大肠杆菌
Combination of technologies works best against E. coli
URBANA -- No one weapon in the food-safety arsenal will take out E. coli 0157:H7, a nasty little pathogen that抯 becoming far too familiar to Americans, say University of Illinois scientists Scott Martin and Hao Feng.
And they should know because they work on this problem in their labs every day. The food science professors work with ozone, high-intensity ultrasound, electrolyzed water, irradiation, and temperature, and they say no treatment singlehandedly can reduce the number of pathogens sufficiently to meet the standards set by the FDA.
"We don抰 believe there抯 any one technique out there that抯 going to be effective," said Martin. "We抮e constantly trying different combinations to achieve the 5-log (99.999 percent) reduction in the number of organisms required by the FDA," he said.
"Obviously maintaining quality is a real challenge because if you do anything very harsh to something like spinach or lettuce, the product won抰 be acceptable even if it抯 pathogen-free," Martin said.
Both scientists believe they抮e getting closer to a solution. "With ultrasound, we can actually damage the pathogen抯 cells to the point that they can抰 be repaired. Ultrasound is a complicated technology, and we抮e still trying to learn how to use it effectively. But this technology causes physical damage--ruptures in the pathogen抯 cells--and that抯 important," said Feng.
In Martin抯 lab, a graduate student has eliminated all Listeria monocytogenes on a stainless steel chip in 30 seconds, using a combination of ultrasound and ozone. This extremely positive result has promising implications for the sanitation of processing equipment, the scientist said.
And Martin said the scientists have reduced the length of time it takes to reach the FDA抯 5-log reduction standard to 30 seconds, which may still be too long for industry. "The thing is we抮e making steady progress," he said.
And the work goes on. Feng抯 use of ultrasound, irradiation, and acidic electrolyzed water to eliminate E. coli on alfalfa and broccoli seeds and his use of high-intensity ultrasound to eliminate E. coli in apple cider were published in the February and June 2006 issues of the Journal of Food Science.
Their work on inactivation of E. coli 0157:H7 with peroxyacetic acid, acidic electrolyzed water, and chlorine on cantaloupes and fresh-cut apples was published in the November 2006 article of the Journal of Food Safety.
"We抳e shown that we have some effective weapons to use against the pathogens that have been in the news so often lately," Martin said. "But we抳e seen the best results when we抳e combined the various technologies." [标签:content1][标签:content2]
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作者:admin@医学,生命科学 2011-05-07 17:14
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