ESTIMATION OF THE THERMOCHEMICAL NONISOTHERMAL INACTIVATION BEHAVIOR OF BACILLUS COAGULANS SPORES IN NUTRIENT BROTH WITH OREGANO ESSENTIAL OIL

Abstract

The aim of this work was to validate the prediction of the nonisothermal thermochemical inactivation of Bacillus coagulans spores in nutrient broth, adjusted to 4 °Brix and pH 4.2, with 400 ppm of oregano essential oil (EO), using the Weibull dynamic model proposed by Peleg. First, the spores were heat treated at four constant temperatures. Afterwards, empirical secondary models were employed to describe the influence of temperature on the primary parameters. Finally, primary and secondary models were used to simulate microorganism inactivation under two nonisothermal temperatures, ranging from 90 to 95C every 1 min; and from 90 to 95C for 5 min at each temperature. Even if a limited experimental data was employed for the nonisothermal analysis, it appears that the proposed model can be used to estimate the nonisothermal inactivation of B. coagulans spores in nutrient broth with 400 ppm of oregano EO. PRATICAL APLICATIONS Oregano essential oil (EO) demonstrates an important antibacterial action against food spoilage microorganisms, as Bacillus coagulans spores. This EO is capable of decreasing the time of the spores' inactivation and, then, the food thermal processing time can be reduced. The industrial heat treatment of foods includes nonisothermal temperatures, as temperature fluctuations during the process, and it is important to understand the behavior of spoilage microorganism all through this temperatures oscillations.

Predicting Bacillus coagulans Spores Inactivation in Tomato Pulp under Nonisothermal Heat Treatments

“…These authors verified that there was general agreement between the predicted and observed survival curves. Haberbeck and others () also tested the applicability of the methodology proposed by Peleg and Penchina () comparing the predicted curves with experimental ones obtained with B. coagulans spore inactivation in nutrient broth, added with 400 ppm of oregano essential oil and heat treated under 2 nonisothermal temperature profiles, ranging from 90 to 95 °C. In contrast to the present work, these authors observed faster experimental inactivation than the model prediction.…”

Advanced mathematical modelling tools for food processing and food safety assessment

“…Consequently, the microbial responses of three microorganisms with different inactivation kinetics have been extracted from the scientific literature: Escherichia coli in peptone water (Garre, Clemente-Carazo, Fernández, Lindqvist, &Egea, 2018), Salmonella enteric subsp. enterica serovar Senftenbergin peptone water (Huertas, Ros-Chumillas, Esteban, Esnoz, &Palop, 2015) and Bacillus coagulansin nutrient broth supplemented with oregano oil (Haberbeck, Dannenhauer, Salomão, & De Aragão, 2013).These microorganisms present survivor curves with different shapes, that include upward and downward concavity, as well as linear responses. Furthermore, their D (and 𝛿) values varies by at least one order of magnitude.…”