Water activity and salt content relationship in moist salted fish products

A linear relationship between water activity (aW) in moist salted fish products and NaCl molality was found: (aW) SF = 1.002–0.042 m; where m is the NaCl molality considering it to be in true solution in the total water content of the product. The linear approximation was analyzed with reference to the aW values of pure NaCl solutions and to a thermodynamic approach for aW prediction; it was found consistent and appropriate for aW estimation in moist salted fish products, with errors within the accepted range for intermediate moisture foods (IMF).