Inactivation kinetics of Alicyclobacillus acidoterrestris spores in orange juice by ohmic heating: effects of voltage gradient and temperature on inactivation.
The effectiveness of ohmic and conventional heating for reducing spores of Alicyclobacillus acidoterrestris was investigated in commercial pasteurized orange juice. The kinetic parameters (D- and z-values) were determined during ohmic and conventional heating. The effects of temperature (70, 80, and 90 degrees C) and heating time (0, 10, 15, 20, and 30 min) on inactivation of A. acidoterrestris spores during ohmic heating in orange juice were significant (P < 0.05). For 70 degrees C, the voltage gradient also had an effect on inactivation kinetics. At 30 V/cm, D-values at 70, 80, and 90 degrees C were 58.48, 12.24, and 5.97 min, respectively. D-values at corresponding temperatures for conventionally heated spores were 83.33, 15.11, and 7.84 min, respectively. Results showed significantly higher lethality for spores treated with ohmic heating than for spores treated with conventional heating. Conventional heating was ineffective for pasteurizing orange juice, whereas the maximum ohmic heating treatment applied at 30 V/cm was sufficient to inactivate 5 log units of A. acidoterrestris spores.
Department of Food Engineering, Izmir Institute of Technology, Urla, 35430, Izmir, Turkey. handanbaysal@iyte.edu.tr
Ayse Handan
AH
Baysal
Filiz
F
Icier
D056450:Alicyclobacillus / Q000502:physiology*; D001628:Beverages / Q000382:microbiology*; D032084:Citrus sinensis / Q000382:microbiology*; D003257:Consumer Product Safety; D004558:Electric Stimulation; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D006358:Hot Temperature; D007700:Kinetics; D013171:Spores, Bacterial / Q000254:growth & development; D013997:Time Factors