Researchers develop cheaper food safety techniques
can cut costs for produce, fruitand vegetable processors, say
The first method uses a laser to detect and identify many types of bacteria, and is about three times faster and one-tenth as expensive as currenttechnology, they claim. A second innovation uses chlorine dioxide gas to kill pathogens on produce, fresh fruits and vegetables.Both have been developed by researchers at Purdue University in Indiana.
Patents are pending on both technologies, and the laser technology is available for licensing.
Increasing concern about food safety has led to a boost in research into quicker and cheapermethods of detecting and killing pathogens. EU and regulatory authorities in member stateshave been increasing their regulation of the industry, resulting in more costs and greater publicscrutiny of manufacturers' operations. Recalls of products are also costly and impact on thecompany's brand image.
"We can use the laser technology to detect problems more quickly, determine exactly what the pathogen is and where it came from,"stated Richard Linton, a professor of food science at Purdue University in Indiana. "As for using this gas as a disinfectant, I would say that in my 13 years of doing research, it is 10,000 to 100,000 times more effective than any process I have seen."
While different in nature, the two methods have the common goal of keeping food safe and preventing people from getting sick, and have each progressed to the point where they could be commercialized,Linton stated.
"Current technologies are insufficient to prevent food-borne illness," he said. "In the present system, once produce is contaminated with something like E. coli, that's it."
Arun Bhunia, who is also a professor of food science, led the team that developed the laser-basedtechnology. The process works by shining a laser though a petri dish containing bacterial colonies. A computer program determines the type of bacteria by analyzing how light isrefracted - as each has a unique "scatter pattern."
Bhunia has shown his technology is capable of recognising Listeria monocytogenes, a microbial pathogen that is the leading cause of food-borne illness. The pathogen has a high mortality rate-one in five-and kills about 500 people each year. E. coli, which has the second highest mortality rate, kills less thanone percent of those infected.
Industry has shown interest in Bhunia's technology, as well as the chlorine dioxide work done by Linton and the project's co-leader, Mark Morgan, a professor of food science.They are currently working on an industrial tunnel system to apply the gas to produce.
His team is also investigating using the gas to sterilize processing equipment. They areinvestigating whether it could speed up sterilisation and eliminate the heat energy currently neededfor the processes.
revious results have shown the gas to be highly effective at killing microbial pathogens. The largest obstacle remaining isto develop a system to dispense the appropriate amount of chlorine dioxide, Morgan said. Enough of the gas must be deployed to kill the pathogens, but too much can cause a decrease of quality in the product, such as browning of leafy greens.
"If the product is safe, but nobody will eat it, that's not what we want," Linton said. "We are always thinking in terms of,'Will this work for industry?' In this case, I believe the answer is yes. I would like to see this technology used regularly by industry in a couple years from now."
Both technologies have the potential to help prevent food-borne illness, Linton said. He alsonoted that following proper agricultural practices is as important, if not more important, for foodsafety.
Since E. coli, or Escherichia coli, is found in the intestines of warm-blooded animals, it does not naturally contaminate most produce. Therefore, following more stringent sanitary policies, as well as practicing better manure and water management, can go a long way to help prevent futureoutbreaks.
E. coli is especially problematic because it only takes as few as 10 cells to infect humans. Other pathogens, like salmonella, need thousands or millions of cells to cause infection.
Bhunia's technology is further described in an article published this summer in the Journal of Biomedical Optics. Linton and Morgan have been working with chlorine dioxide for years, and have several publishedarticles on the subject.
"This would be a large step up from current technologies, which mainly involve washing and scrubbing, and cannot completely rid a product of a pathogen like E. coli,"stated Linton.
A recent outbreak of E. coli from contaminated packaged spinach in the US led to 183 cases of illnessand one death.
"What is happening is unacceptable," Linton stated.