Abstract
Laver (Porphya sp.) containing vitamins and minerals has a high total number of bacteria of 6-7 log CFU/g. Changes in microbial count in dried laver by light pulse, ultrahigh pressure, electron beam, and superheated steam treatment were compared. It was decreased by 1.3-1.7 log using IPL (Intense Pulsed Light) for 30-60 s at an irradiation distance of 80 mm in dried and wet laver. The key parameters of IPL are energy intensity, processing time and irradiation distance. Light pulse inactivation is based on destruction of microbial DNA structure. Electron beam irradiation at 7 and 10 kGy resulted reduction of 1.8-3.2 log CFU/g. Dried laver was treated at 500 MPa of ultra-high pressure for 3 min, total bacterial number showed no change. Applying superheated steam at 150 °C for 10 s, about 3.3 log CFU/g sterilized. However, it is difficult to apply due to severe damage to sensory quality such as browning.