title: Inactivation of Bacillus spores by the combination of moderate heat and low hydrostatic pressure in ketchup and potage.
abstract: The combination effect of moderate heat and low hydrostatic pressure (MHP) on the reduction of Bacillus subtilis, Bacillus coagulans and Geobacillus stearothermophilus spores in food materials (potage and ketchup) was investigated. These bacterial spores were suspended in potage (pH 7), acidified potage (pH 4), neutralized ketchup (pH 7) and ketchup (pH 4). The suspensions were treated with and without pressure (100 MPa) and temperatures of 65-85 degrees C for 3 to 12 h. The bacterial spores were inactivated by 4-8 log cycles during MHP treatment in potage, acidified potage and ketchup, whereas the spores were highly resistant to long time heat treatment in potage and neutralized ketchup. The degrees of spore destruction were mostly dependent on pH and medium composition during MHP treatment. The inactivation effect in MHP treatment was higher at the pH 7 than at pH 4 both in ketchup and potage. The bacterial spores showed higher inactivation in potage than ketchup during MHP treatment.
authors.affiliation: Laboratory of Food Process Engineering, Division of Food Biotechnology, Department of Bioscience and Biotechnology, Faculty of Agriculture, Kyushu University, Higashi-ku, Fukuoka-shi, 812-8581, Japan.
authors.forename: Md Shahidul
authors.initials: MS
authors.lastname: Islam
authors.forename: Ayaka
authors.initials: A
authors.lastname: Inoue
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Igura
authors.forename: Mitsuya
authors.initials: M
authors.lastname: Shimoda
authors.forename: Isao
authors.initials: I
authors.lastname: Hayakawa
mesh_terms: D001407:Bacillus / Q000502:physiology*; D001412:Bacillus subtilis / Q000254:growth & development / Q000502:physiology; D015169:Colony Count, Microbial; D005516:Food Microbiology; D005519:Food Preservation / Q000379:methods*; D001411:Geobacillus stearothermophilus / Q000254:growth & development / Q000502:physiology; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006874:Hydrostatic Pressure; D018551:Solanum lycopersicum / Q000382:microbiology; D013171:Spores, Bacterial / Q000254:growth & development; D013997:Time Factors