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This study was conducted to examine the inhibitory effects of supercritical carbon dioxide (SC‐CO2) on microorganisms in fresh pork. With SC‐CO2 treatment at 120 bar and 40C for 30 min, the initial mesophilic plate counts were reduced from 6.23 to 4.54 log colony‐forming units (cfu) per cm2, and the reduction levels of microorganisms, including nonpathogenic Escherichia coli, Listeria monocytogenes, Salmonella Typhimurium and E. coli O157:H7, ranged from 1.99 to 2.51 log cfu/cm2. Even though SC‐CO2 treatment at 120 bar resulted in higher reductions than treatment at 80 bar, the higher temperature or longer exposure times did not always present greater inhibitory effects than the lower temperature or shorter exposure times. Therefore, from an economic point of view, SC‐CO2 treatment at the lower temperature (35 versus 40C) and shortest exposure time (10 versus 30 min) was more efficient than treatment at the higher temperature or longer exposure time at the same pressure. PRACTICAL APPLICATIONS The practical application of SC‐CO2 has been proposed as an alternative pasteurization technique for various liquid foods. In addition, SC‐CO2 treatment can be used to effectively improve solid food safety including fresh meat and meat products without impairing the quality of the products.

Ground meat has been frequently implicated as a vehicle of pathogenic bacteria. Once microorganisms contaminating the surfaces are embedded within the comminuted meat, they become difficult to inactivate due to the clumpy structure. In this study, we investigated the effectiveness of decontaminating ground pork with supercritical carbon dioxide (SC–CO2) treatment at various conditions (temperatures: 40, 45C; pressures: 100, 120, 140 bar; and treatment times: 20, 30, 40 min). The reduction of microorganisms in ground pork ranged from 1.66 to 2.42 log cfu/g (total mesophilic plate counts, 1.66; Listeria monocytogenes, 2.42; and Salmonella Typhimurium, 2.21 log cfu/g) following SC–CO2 treatment at 45C and 140 bar for 40 min. Even though solid foods were generally difficult to control with SC–CO2, our results indicate that it can be used to reduce the levels of microbes in ground pork through rapid diffusion. Thus, SC–CO2 can be suggested as helpful and novel devices for improving the microbiological safety of comminuted meat products. PRACTICAL APPLICATIONS The SC–CO2 treatment may contribute to reduce the microbial load of pathogenic bacteria contaminated deeply within ground meat in processed meat industries. It can be applied to inactivate bacterial cells of foodborne pathogens including Listeria monocytogenes, Salmonella Typhimurium and other spoiling bacteria, mostly mesophilic bacteria in comminuted meats. The major reason why it is useful especially for meat products is that it can be used at relatively mild condition than heat treatment rarely affecting meat quality. It can penetrate deep into a clumpy structure of ground meat depending on its physical property without toxicity. It is expected that SC–CO2 can be used to sterile ground pork in combination with other antimicrobial co‐solvents to develop microbiological safety of meat products.