Inactivación de formas esporuladas de Bacillus subtilis mediante campos eléctricos pulsantes de alta intensidad en combinacion con otras tecnicas de conservacion de alimentos/Inactivation of Bacillus subtilis spores using high intensity pulsed electric fields in combination with other food conservation technologies

Abstract

The inactivation of Bacillus subtilis spores using high intensity pulsed electric fields (HIPEF) was investigated. Spores were not inactivated when HIPEF treatment (60 kV/cm, 75 pulses) was used alone. The combination of-HIPEF and moderate temperatures around 60°C, and/or the activation of spore suspension prior to HIPEF treatment, and/or the use of up to 5000 IU/ml lysozyme, did not inactivate spores. High hydrostatic pressure (1500 atm, 30 min, 40°C) resulted in the initiation of germination of more than five log cycles in the number of spores, making them sensitive to subsequent pasteurization heat treatment, whereas they were not sensitive to subsequent HIPEF treatment at temperatures less than 40 °C. An intermediate step is needed which allows the outgrowth of spores to vegetative cells. Thus, the combination of high hydrostatic pressure and HIPEF treatment offers an attractive alternative to the stabilization of food products by heat to inactivate spores.