Effects of approved dose of e-beam irradiation on microbiological and physicochemical qualities of dried laver products and detection of their irradiation status.

Most commercial dried laver products show higher microbial contamination. This work evaluated effects of approved dose (7 kGy)-recommended in the Korean Food Code for algal food-of electron beam (E-beam) irradiation on microbiological, physicochemical and luminescence properties of dried laver products. E-beam irradiation caused dose-dependent microbial reductions. For example, a 4 kGy irradiation dose reduced coliform (<2.5 log CFU/g) to undetectable levels (<10 CFU/g), while a 7 kGy irradiation dose reduced total aerobic bacteria count (6.6 log CFU/g) by approximately 2 log cycles. Physicochemical attributes of dried lavers were not significantly (p > 0.05) affected before and after 7 kGy irradiation, but carotenoid content was significantly (p < 0.05) reduced at 10 kGy irradiation. Irradiated samples (>4 kGy) could be detected from non-irradiated ones by luminescence techniques. Overall, results indicated that <7 kGy irradiation is recommended along with other heat treatment for improving microbiological contamination by at most 4 log CFU/g in dried lavers.