Wash. Admin. Code § 16-309-150 – Water activity testing

(1) Water activity (a_w) analysis is intended to quantitatively report out the presence of water in the sample.
The laboratory must run two continuing calibration verifications at levels bracketing the action limit concentration at the beginning of each day of testing.
(2) One sample must be run in duplicate with difference in values of 80 percent - 120 percent as a quality control specimen.
(3) The laboratory must monitor and record temperature and humidity daily or when testing is performed.
(4) The laboratory must calibrate the a_w instrument when:
1. (a) The instrument has been physically moved from one location to another.
2. (b) The instrument has been cleaned.
3. (c) The manufacturer's instruction manual recommends.

[Statutory Authority: RCW 15.150.030 and 2022 c 135. WSR 24-09-079, § 16-309-150, filed 4/17/24, effective 5/18/24.]