Proposed Theoretical Water Activity Values at Various Temperatures for Selected Solutions to Be Used As Reference Sources in the Range of Microbial Growth
419 Journal of Food Protection, Vol. 51, No. 5, Pages 419-423 (May, 1988) Copyright© International Association of Milk, Food and Environmental Sanitarians Proposed Theoretical Water Activity Values at Various Temperatures for Selected Solutions to be Used as Reference Sources in the Range of Microbial Growth SILVIA L. RESNIK1* and JORGE CHIRIFE Downloaded from http://meridian.allenpress.com/jfp/article-pdf/51/5/419/1658009/0362-028x-51_5_419.pdf by guest on 26 September 2021 Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, 1428 Buenos Aires, Republic of Argentina (Received for publication March 26, 1987) ABSTRACT based on the thermodynamic properties of strong electro lyte aqueous solutions, and was applied either to satu This paper compiles recent data on the theoretical prediction rated or unsaturated solutions at different temperatures. of the water activity (a ) of selected saturated salt solutions, w The system of equations developed by Pitzer (7) and his unsaturated NaCl and LiCl solutions, and H2S04 solutions. These results are presented in tabular form in such a way that associates (8,9,14) was successfully used to predict the they can be safely used as reference sources for aw determina aw of selected saturated salt solutions, unsaturated NaCl tion in the range of microbial growth (i.e. about 0.57-0.97) and and LiCl solutions (2,6), and H2S04 solutions (13). at different temperatures. It is the purpose of the present work to compile all these results in such a way that they can be safely used as reference sources for aw determinations in the range Adjustment of the water activity (aw) of foods is an of microbial growth (i.e.
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