Sound Barrier: Can High-Power Ultrasound Protect Produce from Pathogens?
A litany of food scares--and rules for organic produce--have pushed the industry to seek new solutions for food safety
| March 19, 2012 | 5
LEAF BATH: Ultrasound could help improve the washes employed to clean leafy greens today. Image: Courtesy of Earthbound Farms Advances to date in cleaning salad greens have mostly centered on chlorine-based washes and plenty of testing throughout the supply chain. But for organic salad producers, such as Earthbound Farm, a wash additive may not be an option because it has not been approved for organic use. So the company teamed up with the Institute for Food Safety and Health (IFSH) at the Illinois Institute of Technology to look for solutions outside the bag. One of the most promising: high-power ultrasound.
When applied to leafy greens, high-powered ultrasound creates millions of tiny bubbles along a leaf's surface. As they burst at a rate of a thousand times a second, they provide high-energy shock waves that can get into the leaf's nooks and crannies to dislodge pathogens, which are then whisked away in the sanitized wash. (Earthbound is looking at citrus and peracetic acid–based sanitizers, both sanctioned for use with organic products.)
"Mostly we're after E. coli O157:H7; norovirus that causes winter vomiting, and we'll continue working with salmonella and Listeria as well," says IFSH director, Robert Brackett.
Will Daniels, senior vice president of operations and organic integrity at Earthbound, says they hope to move the equipment out of the lab and apply it to their process within the next few months. "That's assuming the pilot studies between now and then are successful and show we don't end up with pureed lettuce at the end of the line. That would be a deal breaker," Daniels adds.
It's not the first time high-powered ultrasound has been used as a sanitizer. The wine industry has used it (pdf) to clean oak barrels since 2006. Employing ultrasound, however, does not guarantee sterile produce, and Earthbound says they will not put forward such a claim.
But early results about its effectiveness in eliminating pathogens are promising—and come at a particularly key time. The U.S. Department of Agriculture's Microbiological Data Program is on the federal chopping block thanks to budget cuts, although it currently tests more than 15,000 samples of fruits and vegetables a year from 11 different produce points across the U.S.
Others in the industry are exploring other sanitization techniques that include ultraviolet light, cold plasma and high pressure to eliminate pathogens on produce. The developers at Earthbound declined to specify the cost of the new ultrasound procedure compared with traditional methods but it will undoubtedly be more expensive—it may add as much as $200,000 to the cost of a sanitation line, according to Cavitus, a company working on the technology.
Organizations like the Center for Produce Safety at the University of California, Davis, have been dispensing research grants to study produce safety. "If you think about a 50-acre field of spinach, it's grown outside and is likely to get contaminated somehow—either through dust-borne E. coli, overflying geese, pigs that get loose. That's the functional reality of things that are grown outside," says Bill Marler, a Seattle-based attorney that specializes in food safety cases.
Smoking may help people regain self-control
Published: Tuesday, Mar 20, 2012, 15:16 IST
Place: Washington, DC | Agency: ANI
Researchers have suggested that smoking may help restore self-control by improving smokers’ positive mood, which may contribute to tobacco addiction. When researchers at Moffitt Cancer Center in Tampa, Fla., deplete smokers’ self control, they found that smoking a cigarette helps restore their self-control. The study exposed a test group and a control group - totalling 132 nicotine dependent smokers - to an emotional video depicting environmental damage. One group in the study expressed their natural emotional reactions (no depletion of self-control) while the second group suppressed their responses (self-control depletion). Half of the participants in each group were subsequently allowed to smoke a cigarette. Everyone then was asked to complete a frustrating task that required self-control. “Our goal was to study whether tobacco smoking affects an individual’s self-control resources,” said lead author Bryan W. Heckman, M.A., a graduate student at the Moffitt Tobacco Research and Intervention Program and the Department of Psychology at the University of South Florida. “We hypothesized that participants who underwent a self-control depletion task would demonstrate less persistence on behavioural tasks requiring self-control as compared to those with self-control intact, when neither group was allowed to smoke. However, we also hypothesized that we would not find this performance decrement among participants who were permitted to smoke,” Heckman stated. The results of the study supported the investigators’ hypotheses. “We found that smoking did have a restorative effect on an individual’s depleted self-control resources. Moreover, smoking restored self-control, in part, by improving smokers’ positive mood,” said Heckman. According to the researchers, evidence is mounting to suggest that self-control is a limited resource that acts like a muscle - expending self-control on a task has the short-term effect of depleting the resource, making it more difficult to engage in another task that requires self-control. While nicotine has been found to enhance performance on a variety of cognitive activities, such as motor abilities, attention and memory, this study was the first to evaluate the effects of smoking on self-control. It suggests that the desire to restore depleted self-control may contribute to smokers’ addiction to tobacco. “Smoking is obviously a maladaptive way to restore self-control,” said study co-author Thomas H. Brandon, Ph.D., chair of the Department of Health Outcomes and Behaviour at Moffitt Cancer Center, and psychology professor at USF. “Finding other ways to relax or enhance one’s mood would be much healthier alternatives. In fact, even raising glucose level - perhaps by consuming a sugary drink - has been shown to restore self-control,” he added. This study also suggested that smokers wanting to quit might benefit from learning such alternative self-control restoration strategies as a way to reduce their dependence on tobacco. The authors concluded that smoking cessation treatments would benefit by further research aimed at identifying how smoking restores self-control, as well as identifying additional alternative strategies for strengthening or restoring self-control. The finding was published in a recent issue of the Journal of Abnormal Psychology. |
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