High-pressure supercritical carbon dioxide uses to inactivate Escherichia coli in pumpkin puree (original) (raw)
Related papers
International Journal of Food Microbiology, 2007
Thermal pasteurization is a well known and old technique for reducing the microbial count of foods. Traditional thermal processing, however, can destroy heat-sensitive nutrients and food product qualities such as flavor, color and texture. For more than 2 decades now, the use of highpressure carbon dioxide (HPCD) has been proposed as an alternative cold pasteurization technique for foods. This method presents some fundamental advantages related to the mild conditions employed, particularly because it allows processing at much lower temperature than the ones used in thermal pasteurization. In spite of intensified research efforts the last couple of years, the HPCD preservation technique has not yet been implemented on a large scale by the food industry until now. This review presents a survey of published knowledge concerning the HPCD technique for microbial inactivation, and addresses issues of the technology such as the mechanism of carbon dioxide bactericidal action, the potential for inactivating vegetative cells and bacterial spores, and the regulatory hurdles which need to be overcome. In addition, the review also reflects on the opportunities and especially the current drawbacks of the HPCD technique for the food industry.
Thermal pasteurization is a well known and old technique for reducing the microbial count of foods. Traditional thermal processing, however, can destroy heat-sensitive nutrients and food product qualities such as flavor, color and texture. For more than 2 decades now, the use of highpressure carbon dioxide (HPCD) has been proposed as an alternative cold pasteurization technique for foods. This method presents some fundamental advantages related to the mild conditions employed, particularly because it allows processing at much lower temperature than the ones used in thermal pasteurization. In spite of intensified research efforts the last couple of years, the HPCD preservation technique has not yet been implemented on a large scale by the food industry until now. This review presents a survey of published knowledge concerning the HPCD technique for microbial inactivation, and addresses issues of the technology such as the mechanism of carbon dioxide bactericidal action, the potential for inactivating vegetative cells and bacterial spores, and the regulatory hurdles which need to be overcome. In addition, the review also reflects on the opportunities and especially the current drawbacks of the HPCD technique for the food industry.
Effect of high pressurized carbon dioxide on Escherichia coli
Tanzania journal of science, 2009
Carbon dioxide at high pressure can retard microbial growth and sometimes kill microorganisms depending on values of applied pressure, temperature and exposure time. In this study the effect of high pressurised carbon dioxide (HPCD) on Escherichia coli was investigated. Culture of E. coli was subjected to high pressurised carbon dioxide at 15, 25 and 35 bar, and varying exposure times of 20, 40, 60 and 90 minutes at room temperature (27 o C). Microbial inactivation increased with pressure and exposure time. For the first 20 minutes reduction of viable microbial cells was 18%, 30% and 36% at 15, 25 and 35 bar, respectively. Higher microbial inactivation values were achieved at 40, 60, and 90 minutes. Decimal reduction times were 127, 93 and 75 minutes at 15, 25, and 35 bar, respectively. The pH values of treated samples decreased with increasing pressure and treatment time from approximately neutral to 5.71 at 15 bar, and 5.02 at 35 bar. It was concluded that high pressurised carbon dioxide has antimicrobial effect on E. coli bacteria. With further studies, HPCD microbial deactivation can be used for foods preservation as a alternative technology to conventional heat pasteurisation and sterilization.
Effects of high-pressure carbon dioxide on Escherichia coli in nutrient broth and milk
International Journal of Food Microbiology, 2001
Bactericidal effects of high-pressure carbon dioxide against Escherichia coli were studied under 100, 75, 50 and 25 bar Ž. at 208C, 308C and 408C. E. coli suspended in nutrient broth NB, pH s 6.75 was inactivated under 100, 75, 50, and 25 bar CO treatments for 50, 65, 100, and 140 min at 308C, respectively. Acidification of nutrient broth by dissolved CO alone 2 2 might account for the bactericidal effect under pressure. E. coli was inactivated in NB with initial pH 5.50 and 4.5 at 100 bar for 80 and 95 min, respectively. Treatment at 100 bar CO pressure for 6 h caused a decrease of 6.42 and 7.24 log 2 cycles in whole and skim milk, respectively.
Journal of Food Science, 2015
High hydrostatic pressure (HHP) is used for microbial inactivation in foods. Addition of carbon dioxide (CO 2) to HHP can improve microbial and enzyme inactivation. This study investigated microbial effects of combined HHP and CO 2 on Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae, and evaluated sensory attributes of treated feijoa fruit puree (pH 3.2). Microorganisms in their growth media and feijoa puree were treated with HHP alone (HHP), or saturated with CO 2 at 1 atm (HHPcarb), or 0.4%w/w of CO 2 was injected into the package (HHPcarb+CO 2). Microbial samples were processed at 200 to 400 MPa, 25°C, 2 to 6 min. Feijoa samples were processed at 600 MPa, 20°C, 5 min, then served with and without added sucrose (10%w/w). Treated samples were analyzed for microbial viability and sensory evaluation. Addition of CO 2 enhanced microbial inactivation of HHP from 1.7-log to 4.3-log reduction in E. coli at 400 MPa, 4 min, and reduction of >6.5 logs in B. subtilis (vegetative cells) starting at 200 MPa, 2 min. For yeast, HHPcarb+CO 2 increased the inactivation of HHP from 4.7-log to 6.2-log reduction at 250 MPa, 4 min. The synergistic effect of CO 2 with HHP increased with increasing time and pressure. HHPcarb+CO 2 treatment did not alter the appearance and color, while affecting the texture and flavor of unsweetened feijoa samples. There were no differences in sensory attributes and preferences between HHPcarb+CO 2 and fresh sweetened products. Addition of CO 2 in HHP treatment can reduce process pressure and time, and better preserve product quality.
Bacterial inactivation on solid food matrices through supercritical CO2: A correlative study
Journal of Food Engineering, 2014
In this paper the effectiveness of dense phase carbon dioxide (DPCD) treatment to inactivate different bacterial strains inoculated on the surface of solid food matrices is studied. The bacterial survival is investigated on three distinct matrices: Salmonella enterica spiked on fresh cut coconut (Cocos nucifera), Escherichia coli on fresh cut carrot (Daucus carota) and Listeria monocytogenes on dry cured ham surface. Bacterial inactivation experiments are carried out in order to develop and identify mathematical models whose relative performance is assessed in terms of goodness-of-fit and a posteriori statistics obtained after parameters estimation. Operational maps illustrating the time required to achieve an assigned inactivation degree are built in order to guide the choice of the best operating conditions to be used in the process.
Effect of Supercritical Carbon Dioxide on the Enzymes Inactivation in Single-Strength Carrot Juice
The inactivation of Pectin Methylesterase (PME), and Peroxidase (POD), in fresh single-strength carrot juice by supercritical carbon dioxide (SCCD) at 40 °C and a CO2/juice ratio (w/w) equal to 3 was investigated. In the range of pressure from 10 to 25 MPa and treatment time from 40 to 110 min, both PME and POD were effectively inactivated significantly. The laboratory inactivation tests were performed by using a semi continuous method with a continuous stream of CO2 fed at constant mass flow rate from the beginning to the end of each experimental test. A semi empirical kinetic model that accounts for a residual equilibrium fraction, , of POD and PME was used to describe satisfactorily the inactivation behavior. Under the above mentioned experimental conditions the pressure dependence of the kinetic constants, , can be described satisfactorily by a constitutive equation that is a linear function of the reduced pressure, , of carbon dioxide. The numerical values of the two model para...
Supercritical CO2 for the drying and microbial inactivation of apple’s slices
Drying Technology, 2019
This study aimed to evaluate the effect of supercritical CO2 process for the inactivation of artificially contaminated seeds of leek and alfalfa. The seeds were inoculated with E. coli O157:H7, Listeria monocytogenes, and Salmonella Thompson and S. Typhimurium and treated at 80 and 120 bar and at 35 and 45°C for 20 min. The process did not influence the germination rate of the seeds. The inactivation was dependent from the type of seed and pressure and temperature. At 120 bar and 45°C E. coli O157:H7, L. monocytogenes, and Salmonella spp. were reduced by 2.92 ± 0.27, 1.14 ± 0.63, and 1.74 ± 0.55 log CFU/g, respectively, on alfalfa and by 4.96 ± 0.37, 2.93 ± 0.27, and 3.18 ± 0.27, respectively on leek. Overall, these results indicated that supercritical CO2 can be used to improve the microbial safety of sprouts, especially for leek.