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In our latest blog, Markon’s Food Safety Director Mario Estrada, Jr. interviews the esteemed Suresh D. Pillai, Ph.D., Director of the National Center for Electron Beam Research at Texas A&M. Dr. Pillai is a Professor of Microbiology and Texas AgriLife Research Faculty Fellow. He holds a joint appointment in the Departments of Nutrition and Food Sciences/Poultry Science. The National Center for Electron Beam Research serves as an unbiased venue for academic, government, and industry scientists, carrying out strategic electronic pasteurization and sterilization research using an electron beam (eBeam) and x-rays. For a full biography of Dr. Pillai, click here.

Electron Beam Irradiation

Q:    Dr. Pillai, can you explain what eBeam irradiation is and how it is used?

A:    Electron beam (eBeam) irradiation also known as eBeam pasteurization, eBeam processing, eBeam treatment, eBeam technology, and electronic pasteurization, is the use of high energy electrons to disinfect/pasteurize/sterilize items such as fresh produce, ground beef patties, medical devices, and pharmaceutical products. The high energy electrons are generated from the electrons contained in commercial electricity using highly specialized equipment called a linear accelerator. One can visualize this technology as fresh produce (that is completely packed in enclosed cases) goes across a conveyor belt under a shower head. The only difference is that instead of water flowing out of the shower, it would be electrons falling onto the produce from the end of the linear accelerator. These electrons break up the DNA and RNA of microorganisms, preventing the growth of spoilage bacteria and if pathogens are present, it would inactivate them. One key advantage of this technique is that it does not cause any heating, meaning that eBeam treatment is a non-thermal technology. One can immediately understand the significant potential of non-thermal microbial inactivation technology for fresh produce. You can use this technology for treating berries, fresh-cut items, or any commodity that is sensitive to heat.

Q:    How safe is it?

A:    This is an extremely safe technology with over 100 years of actual usage in a variety of industries. There are no issues whatsoever to the personnel involved in delivering the doses, nor is there any danger to the fresh produce being treated. Of course, normal industrial occupational safety standards have to be followed when using this technology since the process involves high voltage and energies.

Q:    What are pros and cons of irradiating food products? 

A:    eBeam processing is a non-thermal technology that has significant potential for use in the fresh produce industry. Since no heat is involved, this technology can be used to eliminate microbial pathogens (bacteria, viruses, and protozoa) as well as extend the shelf-life of produce without having to rely on chemicals.

This is a “green technology” with a very low carbon footprint, no use of chemicals, and economically sustainable. The technology can be applied on a variety of commodities, especially those that are highly perishable items such as berries and leafy greens. It is extremely useful in eliminating pathogens on highly vulnerable commodities such as sprouts.

One of the most attractive features of the technology is that it can be used on fully packed items in existing cartons or bags. It’s also inexpensive (four to five cents a pound, even lower depending on volumes) and doesn’t affect the nutrients, sensory qualities, or consumer acceptability.

A key feature of the technology is that it is tunable. At very low doses (150-400 Grays), it can be used to eliminate insects and pests. At slightly higher doses (400- 1000 Grays) it can be used to extend shelf-life and eliminate at least 3-log of microbial pathogens (such as toxigenic E. coli, Salmonella, and protozoa). At even higher doses (1500–4000 Grays) it can achieve 5 to 6-log reduction of a variety of microbial pathogens. Studies in my laboratory have shown that at eBeam doses currently approved by the Food and Drug Administration (namely 4000 Grays), it is possible to achieve between 98% and 99.9% reduction of enteric viruses (poliovirus and rotavirus) on lettuce and spinach.

One of the drawbacks to the technology is that it requires highly specialized equipment, preventing it from becoming widely available. There is also a lot of confusion and misunderstanding about irradiation, even among decision makers in the fresh produce industry. Because anecdotal or erroneous information is often relied upon for decision making about this technology, many choose not to invest in the equipment necessary.

Q:    Is this technology currently being used commercially?

A:    Yes, in the US food industry it is being used on ground beef patties, chubs of ground beef, and on spices. In fresh produce it is currently being used for imported persimmons. Within the next few months the technology will be utilized on imported guavas, mangoes, carambola, sweet limes, and Manzano peppers to control insects and pests. The doses that will be used will be between 400 and 1000 Grays. Even at this low dose, benefits such as an extended shelf-life and 3-log reduction of microbial pathogens can be realized.

Q:     What are some of its applications? 

A:    The applications of this technology include elimination of insects and pests, extension of shelf-life in perishable commodities, elimination of microbial pathogens, and the avoidance of harmful chemicals and fungicides.

Q:    What is the largest sample size that can be effectively treated? 

A:    If customized for the fresh produce industry, the technology can be used to process approximately 20 tons per hour.  

Q:    Is there a quarantine period after processing?

A:    No, there is no quarantine period after processing. The commodities can be placed on market shelves right away or refrigerated for transportation.

Q:    Does it cause any other effects on products?

A:    If the technology is appropriately utilized and within approved guidelines, there are no negative issues whatsoever on the products. 

Q:    What are some of the advantages to eBeam irradiation that cannot be achieved by other means?

A:    This is a non-thermal microbial inactivation technology that has no competition whatsoever by any other technology. It is one of the most widely studied and evaluated technologies.

Q:    Is there anything else you would like to highlight about this technology that we were not able to cover?

A:    The US fresh produce industry is unfortunately slow in adopting this technology. They are incorrectly assuming that consumers will not accept eBeam-treated fresh produce. However, all consumer studies conducted in the US suggest that if consumers are provided the choice, they will purchase these items. Not one such treated commodity or item has been pulled off the shelf due to consumer rejection. The industry needs to spend the time investigating the business models associated with utilizing this technology, rather than relying on erroneous anecdotes. 

Today, irradiated mangoes, guavas, sweet limes, carambola, and persimmons are all marked with the radura symbol and are being sold in US grocery stores. The volume of irradiated fresh produce is actually increasing and will increase significantly in the coming years. New fresh produce distribution companies that deal primarily with eBeam-treated produce are being established. So, if companies are strategic they need to spend the effort to understand the technology and how to employ it strategically.