THERMAL INACTIVATION OF AEROMONAS-HYDROPHILA AS AFFECTED BY SODIUM-CHLORIDE AND ASCORBIC-ACID

The combined effects of sodium chloride (0, 1.0, 1.5, and 3.0%) and ascorbic acid (0, 1.0, and 2.0 mmol/liter) with mild heat (46-degrees-C) on the survival of Aeromonas hydrophila were evaluated. Because of the nonlinear nature of the survivor curves obtained, several equations yielding an R2 (coefficient of multiple determination) of congruent-to 1 were tested. The equation that most closely fit the curvature of the observed data set was a hyperbolic function. Equation coefficients were combined to obtain a so-called death value. This value (46.67% explained variance) was calculated by extracting the larger eigenvalue and the relative eigenvector from the correlation matrix of the coefficients. The effects of the experimental factors on the death value were described by a quadratic response surface model. Results revealed that the death value was not influenced by the presence of ascorbic acid. However, increased mortality resulted from the interaction between sodium chloride and ascorbic acid.