African Journal of
Microbiology Research

  • Abbreviation: Afr. J. Microbiol. Res.
  • Language: English
  • ISSN: 1996-0808
  • DOI: 10.5897/AJMR
  • Start Year: 2007
  • Published Articles: 5211

Full Length Research Paper

Thermal inactivation of Alicyclobacillus acidoterrestris spores isolated from a fruit processing plant and grape juice concentrate in South Africa

Willem H. Groenewald1*, Pieter A. Gouws2 and R. Corli Witthuhn3
1Unit for Applied Food Science and Biotechnology, Central University of Technology, 20 President Brand Street, Bloemfontein 9300, South Africa. 2Department of Biotechnology, University of the Western Cape, Bellville 7535, South Africa. 3Faculty of Natural and Agricultural Sciences, University of the Free State, Park West, Bloemfontein 9300, South Africa.
Email: [email protected]

  •  Accepted: 27 May 2013
  •  Published: 28 May 2013


Thermal inactivation at 95°C for two strains of Alicyclobacillus acidoterrestris isolated from contaminated fruit juice concentrates were investigated in a 0.1% (m/v) peptone buffer solution (pH 7.04) and grape juice (pH 4.02, 15.5 °Brix). The thermal inactivation ofA. acidoterrestris spores followed first-order kinetics, suggesting that as the microbial population is exposed to a specific high temperature, the spores were inactivated at a constant rate. D-values determined in the buffer solution were calculated to be 1.92 ± 0.39 and 2.29 ± 0.50 min, while in grape juice D-values were found to be 2.25 ± 0.53 and 2.58 ± 0.32 min for the two strains tested.


Key words: Alicyclobacillus acidoterrestris, endospores, thermal inactivation, heat resistance, spoilage, fruit juice concentrate, D-value.