Interactions of high hydrostatic pressure, pressurization temperature and pH on death and injury of pressure-resistant and pressure-sensitive strains of foodborne pathogens

Alpas, Hami
The objective of this: study is to determine the interactions between high hydrostatic pressure, pressurization temperature, time and pH during pressurization on death and injury of pressure-resistant and pressure-sensitive strains of four foodborne pathogens: Staphylococcus aureus 485 and 765, Listeria monocytogenes CA and OH2, Escherichia coli O157:H7 933 and 931, Salmonella enteritidis FDA and Salmonella typhimurium E21274. Among these strains S. aureus 485, L. monocytogenes CA, E, coli O157:H7 933 and S, enteritidis FDA were reported to be more pressure-resistant than the respective strain of the same species (Alpas ct al., 1999). In general, viability loss of all pathogens was enhanced significantly as the level of pressure and temperature were increased (P < 0.05). All the strains except S. aureus 485 demonstrated more than 8 log cycle reduction when pressurized at 345 MPa at 50 degrees C for 5 min. This strain seemed to be the most pressure-resistant strain within the conditions of the study. Pressurization in the presence of either citric or lactic acid increased the viability loss by an additional 1.2-3.9 log cycles at pH 4.5 for both acids at 345 MPa. This study has indicated that high hydrostatic pressure applied in conjunction with mild heat and acidity can be an effective method for inactivating pressure-resistant and pressure-sensitive strains of four foodborne pathogens in organic acid solutions. This combination treatment indicates possible pressure pasteurization applications to liquid feuds that have low pH.


Effects of plasmid curing on antibiotic susceptibility, phage type, lipopoly saccharide and outer membrane protein profiles in local Salmonella isolates
İçgen, Bülent; Gültekin, Güzin Candan; Özcengiz, Gülay (Elsevier BV, 2001-12-01)
Five different Salmonella isolates (four Salmonella enteritidis and one Salmonella havana) of human, chicken or egg origin which all expressed smooth lipopolysaccharide were subjected to plasmid curing Upon this treatment, four isolates lost at least one of their resident plasmids while all five isolates became rough in their LPS profiles, Two of the S. enteritidis isolates, CA13 and CE7 were found to convert phage types (PTs) as well. The phage type conversion in CA13 from PT6 to PT21 was found to be accom...
Inactivation of Escherichia coli and Listeria innocua in kiwifruit and pineapple juices by high hydrostatic pressure
Buzrul, Sencer; Alpas, Hami; Largeteau, Alain; Demazeau, Gerard (Elsevier BV, 2008-06-10)
Escherichia coli and Listeria innocua in kiwifruit and pineapple juices were exposed to high hydrostatic Pressure (HHP) at 300 MPa for 5 min. Both bacteria showed equal resistance to HHR Using low (0 degrees C) or subzero (- 10 degrees C) temperatures instead of room temperature (20 degrees C) during pressurization did not change the effectiveness of HHP treatment oil both bacteria in Studied juices. Pulse pressure treatment (multiple Pulses for a total holding time of 5 min at 300 MPa) instead of continuou...
Evaluation of high hydrostatic pressure sensitivity of Staphylococcus aureus and Escherichia coli O157 : H7 by differential scanning calorimetry
Alpas, Hami; BOZOGLU, F; KALETUNC, G (Elsevier BV, 2003-11-01)
Differential scanning calorimetry (DSC) was used to evaluate the relative high hydrostatic pressure (HHP) resistances of bacterial strains from Staphylococcus aureus and Escherichia coli O157:H7 in vivo. The total apparent enthalpy change and thermal stability were two DSC parameters used to compare bacterial strains of untreated control and pressure-treated bacteria. DSC thermograms indicated that ribosomal denaturation appears to be a major factor in cell death by both thermal and high pressure treatments...
Immunization of the industrial fermentation starter culture strain of Saccharomyces cerevisiae to a contaminating killer toxin-producing Candida tropicalis
Izgu, F; Altinbay, D; Derinel, Y (Elsevier BV, 2004-12-01)
K3 killer trait was introduced into the fermentation starter strain of Saccharomyces cerevisiae BSP 1 in order to construct immune industrial strain that produces K3 type killer toxin and was resistant to Candida tropicalis (K+) contamination. Protoplasts of respiration-deficient Rhodegrees strain of S. cerevisiae NCYC 761 (K3) and S. cerevisiae BSP 1 were fused. The resulting respiration-competent hybrid with K3 type killer activity was selected on media containing a non-fermentable carbon source and by a ...
High hydrostatic pressure induced inactivation kinetics of e. coli o157:h7 and s. aureus in carrot juice and analysis of cell volume change
Pilavtepe, Mutlu; Alpas, Hami; Department of Food Engineering (2007)
The main objective of this study was to determine the pressure induced inactivation mechanism of pressure-resistant Escherichia coli O157:H7 933 and Staphylococcus aureus 485 in a low acid food. Firstly, inactivation curves of pathogens were obtained at 200 to 400 MPa at 40ºC in peptone water and carrot juice. First-order and Weibull models were fitted and Weibull model described the inactivation curves of both pathogens more accurately than first-order model, revealing that food systems could exhibit eithe...
Citation Formats
H. Alpas, F. BOZOGLU, and B. RAY, “Interactions of high hydrostatic pressure, pressurization temperature and pH on death and injury of pressure-resistant and pressure-sensitive strains of foodborne pathogens,” INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY, pp. 33–42, 2000, Accessed: 00, 2020. [Online]. Available: