Microbiological and Other Characteristics of Chicken Breast Meat Following Electron-Beam and Sous-Vide Treatments

The combined effects of radiation and sous-vide treatment of chicken breast meat were investigated with respect to survival and growth of Listeria monocytogenes , shelf life, thiamine content, and sensory qualities. Chicken breasts were inoculated with L. monocytogenes 81-861 (10⁵ CFU/g), vacuum-packed, irradiated with electron beam (EB) up to 2.9 kGy, and cooked to an internal temperature of 65.6°C. Sous-vide treatment alone had marginal lethal effect on the L. monocytogenes ; the residual inoculum reached 10⁷ CFU/g after 8 weeks at 2°C. However, after the combined treatments of sous-vide and EB at 2.9 kGy, the organism remained undetectable during the 8-week storage period. Parallel studies on uninoculated breast meat revealed that sous-vide samples had a shelf life of less than 6 weeks without EB treatment, whereas samples that were irradiated and then received sous-vide treatment had a shelf life of at least 8 weeks. There was a slight reduction in thiamine levels as a result of the EB treatment, but there was essentially no additional loss of thiamine due to the subsequent sous-vide treatment and storage at 2°C. Electron-beam treatment had very little effect on the odor and flavor of the reheated samples. It was concluded that EB treatment combined with sous-vide treatment can greatly enhance the microbial safety and shelf life of chicken breast meat.