Microbial Safety of Supercritical Carbon Dioxide Processes

Abstract

The effect of supercritical CO2 (SC‐CO2) processes on the population of Escherichia coli and Staphylococcus aureus was determined in both phosphate buffer solution and ground beef systems at 35, 42.5 and 50C/10.34, 20.67 and 31.03 MPa. Higher pressures and temperatures significantly decreased the D‐values of both bacteria. No cells survived at 50C. E. coli was more resistant to SC‐CO2 processes than was S. aureus in phosphate buffer solution at 35C and in ground beef at 42.5C. After applying SC‐CO2 at 35C for 1 h in a phosphate buffer solution, pH values dropped from 6.6–6.8 to 3.7–3.9 at each pressure and remained relatively constant at that level for 6 h. While the count of S. aureus recovered completely after 18 h of incubation, under similar conditions E. coli did not.

Inactivation of Staphylococcus aureus in raw salmon with supercritical CO2 using experimental design

“…According to this author, the nature of the matrix and the presence of compounds such as carbohydrates and fats may play an important role in microorganism protection. Similar results were also obtained by Sirisee et al (1998), who tested the SC-CD 2 tolerance (35 to 50 °C and 100 to 310 bar) of Escherichia coli and S. aureus inoculated into ground beef and higher pressures and temperatures significantly decreased the D-values of both bacteria and no cells survived at 50 °C. Meujo et al (2010) studied the effect of the supercritical CD 2 in microbial inactivation of entire oysters, obtaining 2 and 3 logarithmic reductions in the aerobic microorganisms count, under the conditions 100 bar and 37 °C for 30 minutes and 172 bar and 60 °C for 60 minutes, respectively.…”

Non-thermal inactivation of Escherichia coli K12 in buffered peptone water using a pilot-plant scale supercritical carbon dioxide system with a gas–liquid porous metal contactor

“…For example, Kamihira et al (1987) observed that E. coli in physiological saline was reduced by about 5-6 logs with a batch system at 10-20 MPa and 35°C for 120 min. Sirisee, Hsieh, and Huff (1998) found that the number of E. coli in phosphate buffer solution decreased 1.2 and 7.8 logs at 35 and 42.5°C at a pressure of 10.34 MPa. However these batch methods had limitations such as long exposure time which may preclude commercialization.…”

Effect of supercritical carbon dioxide on inactivation and germination of Alicyclobacillus acidoterrestris spores

“…W ostatnich latach obserwuje się rozwój wielu nowych i alternatywnych metod utrwalania żywności, w tym soków owocowowarzywnych, m.in. stosowanie wysokich ciśnień hydrostatycznych [12,21,25,28], pulsacyjnych pól elektrycznych [10], ogrzewania mikrofalowego w przepływie [9,26] oraz nadkrytycznego ditlenku węgla [6,17,23,24].…”