Manothermosonication (MTS) treatment of apple-carrot juice blend for inactivation of Escherichia coli 0157:H7

This study was performed to evaluate the responses of Escherichia coli 0157:H7 inoculated in an apple carrot blended juice to manothermosonication (MTS) treatments. The MTS treatments were conducted in a continuous -flow MTS system. The juice samples were exposed to ultrasound treatment at combinations of three temperatures (60, 50 and 40 degrees C) and three pressure levels (100, 200, and 300 kPa) for five residence times (15, 30, 45, 60, and 75 s). The results showed that higher treatment temperature (i.e. 60 degrees C) and hydrostatic pressure in the MTS system significantly enhanced the microbial reduction. A FDA mandated 5-logCFU/ml reduction of E. coli 0157:H7 for juice processing was achieved in 30 s for MTS treatment at 60 degrees C, in comparison to 60 s at 50 degrees C. The Weilbull and Log -logistic models provided the best fitting of the inactivation data for the MTS treatments. Extensive damage of E. coli 0157:H7 cells treated with MTS was observed on micro-images of scanning electron microscopy and transmission electron microscopy. (C) 2016 Elsevier B.V. All rights reserved.