Combined effect of organic acids and supercritical carbon dioxide treatments against nonpathogenicEscherichia coli,Listeria monocytogenes,Salmonella typhimuriumandE. coliO157:H7 in fresh pork

Abstract

To evaluate the effectiveness of organic acids and supercritical carbon dioxide (SC-CO(2)) treatments as well as their combined effect for the reduction of nonpathogenic Escherichia coli and three pathogenic bacteria in fresh pork. The different treatment conditions were as follows: (i) treatment with acetic (1%, 2% or 3%) or lactic acid (1%, 2% or 3%) only, (ii) treatment with SC-CO(2) at 12 MPa and 35 degrees C for 30 min only and (iii) treatment with 3% acetic or lactic acid followed by treatment with SC-CO(2). Within the same organic acid concentration, the lactic and acetic acid treatments had similar reductions. For the combined treatment of lactic acid and SC-CO(2), micro-organism levels were maximally reduced, ranging from 2.10 to 2.60 log CFU cm(-2) (E. coli, 2.58 log CFU cm(-2); Listeria monocytogenes, 2.60 log CFU cm(-2); Salmonella typhimurium, 2.33 log CFU cm(-2); E. coli O157:H7, 2.10 log CFU cm(-2)). The results of this study indicate that the combined treatments of SC-CO(2) and organic acids were more effective at destroying foodborne pathogens than the treatments of SC-CO(2) or organic acids alone. The combination treatment of SC-CO(2) and organic acids may be useful in the meat industry to help increase microbial safety.