5-5 |
Inactivation of viruses and protozoa by E-beam technology |
S. D. PILLAI, Poultry Science Dept., Texas A&M Univ., 418 Kleberg Ctr., 2472 TAMU, College Station, TX 77843-2472 Viral and protozoan decontamination of foods and drinking water is a key step in the protection of public health. Even though E-beam technology has been proven to be effective against bacterial pathogens and protozoa, ionizing radiation is generally thought to be less effective against viruses. It has been argued that the reduced size of viruses is responsible for the reduced ineffectiveness. The mechanism of microbial inactivation by E-beam is believed to be the nucleic acid targets. The nucleic acid may be directly damaged or there may be indirect damage due to OH radicals originating from water. The extent of indirect damage can, however, be modulated by the presence of scavengers such as bicarbonate. In addition to nucleic acid damage, there are reports that the protein coat may also be the site of ionizing radiation damage. Studies conducted using DNA and RNA viruses suggest that 10KGy of E-beam irradiation is capable of achieving a 4-log reduction of a DNA virus compared to a 3-log reduction of RNA virus. The suspending matrix was found to be a profound impact on the viral inactivation suggesting that the indirect effects of ionizing radiation may be the primary factor responsible for viral inactivation. This is also based on detection of amplifiable viral nucleic acid fragments from the irradiated samples. Peptone containing matrix was found to protect viruses from ionizing radiation compared to distilled water, balanced salt solutions and secondary effluent.
Session 5, E-Beam technology: Where are we in terms of the science?
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