Irradiation of bulk or prepackaged foods is achieved by exposing the product to a source of ionizing energy, typically Cobalt-60. The product to be treated is conveyed through a shielded chamber containing the radiation source, and irradiation dosage is controlled by the speed of the conveyor. Inactivation of organisms by ionizing radiation is primarily due to DNA damage, which destroys the reproductive capabilities and other functions of the cell.
The lethal effect of ionizing radiation is not greatly enhanced by mild acidification. For example, the destruction of bacteria in and the shelf life of irradiated chicken and ground beef were not improved by low concentrations of infused or added acetic acid. In another study, the differences in pH of five commercial orange juice formulations (from pH 3.87 to 4.13) had no influence on the radiation dose required for 90% inactivation of a Salmonella Enteritidis strain isolated from a citrus juice associated with an outbreak of salmonellosis.
investigated irradiation combined with pH reduction (with different acidulants) for their effects on the shelf life of a chilled and temperature abused beef/pork product. Bacteria of the Enterobacteriaceae family were both destroyed and injured by irradiation, and injured cells
were unable to grow at the acidic pH even in temperature abused product. Radiation-resistant lactic acid bacteria subsequently became the dominant microflora, suggesting that the selection for lactic acid bacteria in irradiated foods might serve as an intrinsic factor for control of the growth of certain pathogens.
Irradiation of bulk or prepackaged foods is achieved by exposing the product to a source of ionizing energy, typically Cobalt-60. The product to be treated is conveyed through a shielded chamber containing the radiation source, and irradiation dosage is controlled by the speed of the conveyor. Inactivation of organisms by ionizing radiation is primarily due to DNA damage, which destroys the reproductive capabilities and other functions of the cell.
The lethal effect of ionizing radiation is not greatly enhanced by mild acidification. For example, the destruction of bacteria in and the shelf life of irradiated chicken and ground beef were not improved by low concentrations of infused or added acetic acid. In another study, the differences in pH of five commercial orange juice formulations (from pH 3.87 to 4.13) had no influence on the radiation dose required for 90% inactivation of a Salmonella Enteritidis strain isolated from a citrus juice associated with an outbreak of salmonellosis.
investigated irradiation combined with pH reduction (with different acidulants) for their effects on the shelf life of a chilled and temperature abused beef/pork product. Bacteria of the Enterobacteriaceae family were both destroyed and injured by irradiation, and injured cells
were unable to grow at the acidic pH even in temperature abused product. Radiation-resistant lactic acid bacteria subsequently became the dominant microflora, suggesting that the selection for lactic acid bacteria in irradiated foods might serve as an intrinsic factor for control of the growth of certain pathogens.
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