Steam-baking for disinfection of dehydrated Porphyra yezoensis

In industrial production, the baked seaweed snack (BSS) is prepared by baking dehydrated Porphyra yezoensis. This study revealed that total aerobic bacteria (TAB) counts in raw dehydrated P. yezoensis ranged from 2.36 to 7.15 log CFU/g. Remarkably, these microbial populations were found to survive conventional processing protocols, including high-temperature baking (180–220 °C for 11–38 s) or two-stage thermal treatments involving disinfection at 110–160 °C for 5–15 min followed by final baking at 200 °C. To address this challenge, steam-baking (STB) pretreatment was applied to raw dehydrated P. yezoensis using a steam oven. The results demonstrated that STB treatment at 120–150 °C effectively inactivated bacteria without compromising the quality of the final BSS. Microbial survival curves during STB were well-fitted by the Weibull model. Notably, 150 °C STB treatment for 5 min directly converted dehydrated P. yezoensis into BSS, eliminating the need for additional high-temperature baking at 200 °C. This study establishes STB as a promising technology for disinfecting dehydrated P. yezoensis raw materials and substantially enhancing the microbiological quality of BSS while maintaining product integrity.