Medycyna Wet. 63 (5), 515-518, 2007
| Malinowska-Pańczyk E., Kołodziejska I. |
| Combined effect of high pressure and other antimicrobial factors on inactivation of microorganisms |
| High pressure can be used as an alternative for inactivation of microorganisms to traditional, thermal methods. A high pressure technique has been already applied in the food industry, primarily to preserve acidic food products such as fruit juices and jams. However, this method does not guarantee a complete inactivation of microorganisms at moderate temperature in food with pH close to neutral. Therefore the possibility of using high pressure in connection with other antimicrobial factors has been studied, mainly with lysozyme, bacteriocins and CO2. High pressure increases the bacteriostatic effect of bacteriocins on different vegetative cells of gram-negative and gram-positive bacteria and vice versa, the bacteriocins enhance the sensitivity of microorganisms to high pressure. Such increased inactivation of bacteria occurs also when the cells are treated by high pressure in the presence of pediocin AcH, but the degree of inactivation significantly depends on the species of microoganisms. A synergistic lethal effect in relation to gram-positive bacteria as well as to gram- -negative bacteria has been observed due to the combined action of high pressure and lysozyme; however, the reduction in the number of viable cells was not higher than 1-2 log cycles. For inactivation of bacteria, bacterial spores, and fungi, treatment with CO2 under pressure can be used. An increase in temperature and pressure favors the penetration of CO2 through the cell membranes and lowers the internal pH, thereby inactivating the key enzymes participating in cell metabolism and in regulating processes. High pressure and ionizing radiation can be used to reduce the irradiation dose and thus prevent undesirable changes of food components. |
| Keywords: high pressure, microorganisms |