title: Thermal inactivation kinetics of Bacillus coagulans spores in tomato juice.
abstract: The thermal characteristics of the spores and vegetative cells of three strains of Bacillus coagulans (ATCC 8038, ATCC 7050, and 185A) in tomato juice were evaluated. B. coagulans ATCC 8038 was chosen as the target microorganism for thermal processing of tomato products  due to its spores having the highest thermal resistance among the three strains. The thermal inactivation kinetics of B. coagulans ATCC 8038 spores in tomato juice between 95 and 115°C were determined independently in two different laboratories using two different heating setups.  The results obtained from both laboratories were in general agreement, with z-values (z-value is defined as the change in temperature required for a 10-fold reduction of the D-value, which is defined as the time required at a certain temperature for a 1-log reduction of  the target microorganisms) of 8.3 and 8.7°C, respectively. The z-value of B. coagulans 185A spores in tomato juice (pH 4.3) was found to be 10.2°C. The influence of environmental factors, including cold storage time, pH, and preconditioning, upon the thermal resistance  of these bacterial spores is discussed. The results obtained showed that a storage temperature of 4°C was appropriate for maintaining the viability and thermal resistance of B. coagulans ATCC 8038 spores. Acidifying the pH of tomato juice decreased the thermal resistance of these  spores. A 1-h exposure at room temperature was considered optimal for preconditioning B. coagulans ATCC 8038 spores in tomato juice.
authors.affiliation: Department of Biological Systems Engineering, Washington State University, Pullman, WA 99163, USA.
authors.forename: Jing
authors.initials: J
authors.lastname: Peng
authors.forename: Jae-Hyung
authors.initials: JH
authors.lastname: Mah
authors.forename: Romel
authors.initials: R
authors.lastname: Somavat
authors.forename: Hussein
authors.initials: H
authors.lastname: Mohamed
authors.forename: Sudhir
authors.initials: S
authors.lastname: Sastry
authors.forename: Juming
authors.initials: J
authors.lastname: Tang
mesh_terms: D019540:Area Under Curve; D001407:Bacillus / Q000502:physiology*; D001628:Beverages / Q000382:microbiology*; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005516:Food Microbiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D018551:Solanum lycopersicum / Q000382:microbiology*; D050296:Microbial Viability; D013171:Spores, Bacterial / Q000254:growth & development