Modelling the effect of the treatment medium ph on the heat inactivation of enterococcus faecium using multiple regression analysis

الملخص EN

-soy broth of different pH (4.0, 5.5 and 7.4) was studied.

The bacterial cells were more sensitive at higher temperature and in media of low pH.

Decimal reduction times at 71ºC were 2.56, 0.39 and 0.03 min at pH 7.4, 5.5 and 4.0 respectively.

At all temperatures and pH assayed, the survival curves obtained were linear.

A mathematical model based on the first order kinetic accurately described these survival curves.

The relationship between DT values and temperature was also linear.

A mean z-value of 5ºC was established.

A multiple linear regression model using four predictor variables (pH, T, pH2 and T2) related the Log of DT value with pH and treatment temperature.

The developed tertiary model satisfactorily predicted the heat inactivation of Enterococcus faeciumunder the treatment conditions investigated.