Use of electron beam irradiation on spinach and lettuce can significantly cut virus-related foodborne illnesses, said scientists as they questioned why take up of the technology was not greater by fresh produce industry players.
The scientists from the US and Mexico said the results of its study could contribute to the safety of the leafy green vegetables and they hoped the findings would trigger public calls for the greater adoption of E-beam irradiation equipment in the sector.
At present, industry reluctance combined with consumer apathy and ignorance were curbing wider E-beam treatment that could reduce human suffering and save billions of dollars in health care costs.
Industry ignoring safety tool
The research, published in the journal, Applied and Environmental Microbiology, said it could be the first to quantify such bug count reductions in lettuce and spinach - the only fresh produce approved for E-beam treatment by the US Food and Drug Administration (FDA).
"This study provides quantified data that electron-beam technology reduces the risk of viral foodborne illness in lettuce and spinach," said Dr. Suresh Pillai, director for the National Center for Electron Beam Research at Texas A&M University in College Station. "But so far the fresh produce industry has not adopted this technology. It's similar to auto manufacturers having a supply of seat belts but not installing them in their vehicles.”
The lead researcher added: "We hope it will lead to greater public demand for the use of this technology as part of good agricultural and post-harvest practices."
The study aimed to determine the sensitivity of poliovirus and rotavirus to E-beams on fresh cut lettuce and spinach and quantify the theoretical reduction in the health risk at different contamination levels and E-beam doses.
Pillai said the study was important as viruses are the primary cause of foodborne illnesses, with associated healthcare costs running to US$6bn annually.
The project focused on enteric viruses, such as poliovirus and rotavirus, rather than the more prolific norovirus, as these can lead to chronic disease complications. These viruses can contaminate fresh produce through irrigation water containing fecal matter or by tainted wash water.
E-beam technology was selected because of its potential for worldwide use because it is “based on electricity and is basically a switch-on, switch-off type technology," said Pillai.
Lettuce and baby spinach samples were inoculated with rotavirus and poliovirus and exposed to doses of E-beams.
The scientists found that exposing a 14-gram serving of lettuce containing 140 poliovirus particles to the ionizing radiation at 3 kilograys (kGy), showed a significant infection reduction risk; from greater than two in 10 people, or 20%, to approximately six in 100, or 6%.
For a serving size of spinach contaminated with approximately 10 rotavirus particles, E-beam irradiation at 3 kilograys reduced infection risks from about three in 10 people, or 30%, to about five in 100 persons, or 5%.
Pillai said that while the results demonstrated the capability of E-beam to combat the viruses, the technology is not meant to be a stand-alone process but rather used as part of a comprehensive safety programme.
Lack of consumer demand for safe food
The researcher told FoodProductionDaily.com there were multiple reasons for the lack of E-beam adoption in the sector. If irradiated leafy greens were sold at retailers, the companies would face the dilemma of why some fresh products on sale were “microbiologically safe”, while some non-irradiated foods may be “inherently pathogen contaminated”, said Pillai.
“It’s similar to an auto dealer selling the same car with and without safety features,” he added.
Players in the fresh produce sector had made little effort to monetize and market the technology to the public. Consumer doubts could be overcome if they are given full information about its benefits, said Pillai.
A further key reason is that consumers are not demanding safe food products and this lack of awareness and demand meant the industry was not interested in making irradiated products available.
Pillai said: “It is quite remarkable that consumers are not demanding such safe food products while [they] are willing to stand for days to purchase a new iPhone or any other consumer item.”
Quantifying the Reduction in Potential Health Risks by Determining the Sensitivity of Poliovirus Type 1 Chat strain and Rotavirus SA-11 to E-Beam Irradiation of Iceberg Lettuce and Spinach by Ana Cecilia Espinosa, Palmy Jesudhasan, René Arredondo, Martha Cepeda, Marisa Mazari-Hiriart, Kristi D. Mena, Suresh. Pillai published in Applied and Environmental Microbiology; doi: 10.1128/AEM.06927-11