Development and validation of predictive models for the effect of storage temperature and pH on the growth boundaries and kinetics of Alicyclobacillus acidoterrestris ATCC 49025 in fruit drinks

Myrsini Kakagianni; Kelly Kalantzi; Evangelos Beletsiotis; Dimitrios Ghikas; Alexandra Lianou; Konstantinos P Koutsoumanis

doi:10.1016/j.fm.2018.02.019

Development and validation of predictive models for the effect of storage temperature and pH on the growth boundaries and kinetics of Alicyclobacillus acidoterrestris ATCC 49025 in fruit drinks

Food Microbiol. 2018 Sep:74:40-49. doi: 10.1016/j.fm.2018.02.019. Epub 2018 Feb 28.

Authors

Myrsini Kakagianni¹, Kelly Kalantzi², Evangelos Beletsiotis², Dimitrios Ghikas², Alexandra Lianou³, Konstantinos P Koutsoumanis⁴

Affiliations

¹ Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece.
² Department of Molecular Microbiology, Quality Assurance Division, Delta Foods S.A., 23rd km National Road Athens-Lamia, 145 65 Agios Stefanos, Greece.
³ Laboratory of Microbiology and Biotechnology of Foods, Department of Food Science and Human Nutrition, School of Food, Biotechnology and Development, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece.
⁴ Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Faculty of Agriculture, Forestry and Natural Environment, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece. Electronic address: kkoutsou@agro.auth.gr.

PMID: 29706336
DOI: 10.1016/j.fm.2018.02.019

Abstract

This study was undertaken to provide quantitative tools for predicting the behavior of the spoilage bacterium Alicyclobacillus acidoterrestris ATCC 49025 in fruit drinks. In the first part of the study, a growth/no growth interface model was developed, predicting the probability of growth as a function of temperature and pH. For this purpose, the growth ability of A. acidoterrestris was studied at different combinations of temperature (15-45 °C) and pH (2.02-5.05). The minimum pH and temperature where growth was observed was 2.52 (at 35 and 45 °C) and 25 °C (at pH ≥ 3.32), respectively. Then a logistic polynomial regression model was fitted to the binary data (0: no growth, 1: growth) and, based on the concordance index (98.8%) and the Hosmer-Lemeshow statistic (6.226, P = 0.622), a satisfactory goodness of fit was demonstrated. In the second part of the study, the effects of temperature (25-55 °C) and pH (3.03-5.53) on A. acidoterrestris growth rate were investigated and quantitatively described using the cardinal temperature model with inflection and the cardinal pH model, respectively. The estimated values for the cardinal parameters T_min, T_max, T_opt and pH_min, pH_max, pH_opt were 18.11, 55.68, 48.60 °C and 2.93, 5.90, 4.22, respectively. The developed models were validated against growth data of A. acidoterrestris obtained in eight commercial pasteurized fruit drinks. The validation results showed a good performance of both models. In all cases where the growth/no growth interface model predicted a probability lower than 0.5, A. acidoterrestris was, indeed, not able to grow in the tested fruit drinks; similarly, when the model predicted a probability above 0.9, growth was observed in all cases. A good agreement was also observed between growth predicted by the kinetic model and the observed kinetics of A. acidoterrestris in fruit drinks at both static and dynamic temperature conditions.

Keywords: Alicyclobacillus acidoterrestris; Fruit drinks; Growth boundaries; Growth model.

MeSH terms

Alicyclobacillus / growth & development*
Beverages / microbiology
Food Microbiology*
Food Storage*
Fruit / microbiology
Fruit and Vegetable Juices / microbiology*
Hydrogen-Ion Concentration*
Kinetics
Logistic Models
Models, Biological
Spores, Bacterial / growth & development
Temperature*