URBANA -- No one weapon in the food-safety arsenal will take out E. coli 0157:H7, a nasty little pathogen thats 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 dont believe theres any one technique out there thats going to be effective," said Martin. "Were 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 wont be acceptable even if its pathogen-free," Martin said.
Both scientists believe theyre getting closer to a solution. "With ultrasound, we can actually damage the pathogens cells to the point that they cant be repaired. Ultrasound is a complicated technology, and were still trying to learn how to use it effectively. But this technology causes physical damage--ruptures in the pathogens cells--and thats important," said Feng.
In Martins 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 FDAs 5-log reduction standard to 30 seconds, which may still be too long for industry. "The thing is were making steady progress," he said.