Review High pressure carbon dioxide inactivation of microorganisms in foods: The past, the present and the future Step 1: solubilization of pressurized CO 2 in the external liquid phase (original) (raw)
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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.
Modern Concepts & Developments in Agronomy, 2018
Dense phase CO 2 (DPCD) is a non-thermal technology that can inactivate certain microorganisms and enzymes at temperatures low enough to avoid the thermal effects of traditional pasteurization. This technology has been investigated over the past 50 years, particularly in the past 2 decades, and its effects on vegetative cells and spores of various microorganisms including pathogens, spoilage bacteria, yeasts, and molds, and various enzymes of importance to foods have been demonstrated. Many liquid foods retained fresh-like sensory, nutritional, and physical properties after DPCD treatment along with some solid foods. This paper is a review of mechanisms of microbial reduction, enzyme and spore inactivation, DPCD treatment systems and examples of applications with effects on quality attributes.
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.
International Journal of Food Science & Technology, 1999
Non-thermal inactivation of Lactobacillus plantarum cells as influenced by pressure and temperature of pressurized carbon dioxide was investigated to evaluate its potential use for preservation of foods and biological substances. Microbial inactivation by the pressurized CO 2 was dependent principally on the transfer rate of CO 2 into cells and effectiveness could be improved by increasing pressure and temperature. Microbial reduction of more than 6 logs occurred within 30 min under CO 2 pressure of 2000 psi at 30 ЊC. The results showed that the pressurized CO 2 treatment could be used as a potential non-thermal preservation technology for foods.
High-pressure supercritical carbon dioxide uses to inactivate Escherichia coli in pumpkin puree
Research, Society and Development, 2021
Coli ATCC 25922 inactivation was studied to determine the effect of high-pressure carbon dioxide (HPCD) process on pumpkin puree. Experiments were performed using a batch HPCD system at three conditions of pressure (7.5 MPa, 17.5 MPa and 27.5 MPa) at 32 °C. Afterwards, at the best experimental condition (27.5 MPa – 275 bar), a kinetic was performed to assess inactivation of microorganisms over time (from 1 to 8 h). The physicochemical characteristics (pH, total soluble solids – TSS, titratable acidity – TA, total carotenoids, total reducing sugars – TRS, moisture and optical microscopy) of the pumpkin puree were also evaluated. HPCD with acidification increases bacterial efficacy of treatments, as well as significant changes in physicochemical parameters. HPCD treatment reduced the microbial load moderately in all experiments, by a maximum of approximately 3.17 log cycles in 8 h of process at 27.5 MPa (275 bar). Optical microscopy showed no difference in cell wall, just in starch wh...
Journal of Supercritical Fluids, 2009
The feasibility of high pressure carbon dioxide (HPCD) processing as a non-thermal pasteurization technique for liquid whole egg (LWE) was investigated. First, the influence of process parameters including temperature, pressure, agitation speed, working volume ratio (WVR) and holding time on the reduction of the natural microbial flora of LWE was studied. Temperature, WVR and stirring speed were the most important parameters in HPCD inactivation. HPCD processing at 13.0 MPa, 45 • C, 50% WVR and 400 min −1 stirring speed during 10 min proved promising for inactivating the native microorganisms in LWE. Secondly, the effect of HPCD treatment at these "optimal" conditions was evaluated on the microbial quality and pH of LWE under refrigerated storage (4 • C) and compared to stored heat pasteurized samples (69 • C, 3 min). HPCD processing extended the shelf life of LWE up to 5 weeks at 4 • C, which is the current shelf life of heat pasteurized LWE. No pH difference was detected between HPCD and heat treated LWE after 1 week of storage.
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.
Inactivation Kinetics of Lactobacillus plantarum by High Pressure Carbon Dioxide
Journal of Food Science, 1999
Inactivation kinetics of Lactobacillus plantarum by high pressure CO 2 was investigated to understand the mechanism of microbial inactivation. The inactivation rates increased with pressure, temperature and exposure time, and with decreasing pH of media. Microbial inactivation was governed essentially by penetration of CO 2 into cells and its effectiveness could be improved by the enhanced transfer rate. Microbial reduction of 8 log cycles was observed within 120 min under CO 2 pressure of 70 kg/cm 2 at 30°C. We hypothesized that the cell death resulted from the lowered intracellular pH and damage to the cell membrane due to penetration of CO 2. Pressurized CO 2 treatment is a potential nonthermal technology for food preservation.
The Journal of Supercritical Fluids, 2010
Experimental survival curves of Saccharomyces cerevisiae cells exposed to high pressure carbon dioxide (HPCD) treatments under several constant temperatures (35, 40 and 50 • C), pressures (7.5, 10.0 and 13.0 MPa) and suspended in distilled water with different sodium phosphate monobasic buffer concentrations (0.02, 0.10, 0.20 and 0.40 M) were obtained. The Peleg model was applied to the isobaric and isothermal conditions described by the power law equation log[S(t)] = −bt n , where S(t) is the momentary survival ratio and 'b' and 'n' are the rate and the shape parameters, respectively. The values of the coefficients 'b' and 'n' were calculated for each experiment at fixed pressure and temperature. For each suspending medium the power law model was proposed to describe the combined effects of pressure and temperature. Taking into account the CO 2 solubility as a function of the sodium phosphate monobasic concentration, 'b' and 'n' were correlated to the CO 2 solubility values and temperature. An equation was proposed for 'b' as a function of CO 2 solubility and temperature while 'n' was a weak function of temperature. The resulting equation was much simpler that the one obtained correlating the microbial inactivation to pressure and temperature and, more important, it was independent of the suspending medium. The results indicate that the coupling of carbon dioxide solubility, also predicted with commercial software, and the use of inactivation models referred to solubility and temperature may provide a powerful instrument for the interpretation of microbial inactivation experiments and for the design of HPCD processes and equipments.