Modeling Heat-Resistance of Alicyclobacillus acidoterrestris in Different Fruit Juices: Combined Effects of pH and Temperature

Abstract

This study evaluated the efficacy of pH and temperature on the thermal resistance of Alicyclobacillus acidoterrestris endospores in different fruit juices. A polynomial equation was used to describe the pH x temperature impact on the D-values of endospores. Endospore resistance was influenced by fruit juice matrices. Maximum heat resistance was found in passion fruit juice (D value 24.7±2.8 min, 90 ºC, pH 4.5) and the greatest thermal destruction was observed in papaya juice (D value 1.7±2.8 min, 95 °C, pH 2.5). Regardless of the fruit juice, endospore thermal destruction was more effective at 95 °C. In both temperatures analyzed, the effect of pH on the reduction of heat resistance was more pronounced in papaya juice. According to the mathematical models, the interaction pH x temperature had the greatest impact on endospores thermal reduction. These results emphasize the relevance of time⁄temperature binomials to prevent spoilage by A. acidoterrestris in thermal treated fruit juices.

Keywords:
inactivation model; D-values; spoilage; thermoacidophilic bacteria.

HIGHLIGHTS

• The food juice matrix influences thermal resistance of A. acidoterrestris.

• Alicyclobacillus thermal resistance is affected by pH x temperature combinations.

• Mathematical models predict heat and pH effect on D-values and endospore survival.