2.3. Creation of a 23% relative humidity environment
To create a 23% atmospheric RH environment, 100 ml of saturated potassium acetate (Daejung, Siheung, Republic of Korea) solution (aw 0.230 ± 0.005) was prepared, deposited in an airtight container (1.2 L,132 mm long132 mm wide71 mm high; Lock & Lock, Seoul, Republic of Korea), and stored at 45 C or 80C for at least 24 h prior to use in experiments.