Inactivation of Salmonella enteritidis, Salmonella Typhimurium, and Salmonella Senftenberg by ultrasonic waves under pressure

The resistance of Salmonella Enteritidis (ATCC 13076), Salmonella Typhimuri um (ATCC 13311), and Salmonella Senftenberg 775W (ATCC 43845) to ultrasonic waves under pressure treatments, at sublethal (manosonication) and lethal temperatures (manothermosonication) in citrate-phosphate buffer and in liqu id whole egg was investigated. The influence of treatment parameters on the inactivation rate of manosonication was also studied. Decimal reduction ti mes (D-t) of Salmonella Enteritidis, Salmonella Typhimurium, and Salmonella Senftenberg 775W corresponding to a heat treatment at 60 degrees C in pH 7 buffer and in liquid whole egg were 0.068, 0.12, and 1.0 min for buffer, a nd 0.12, 0.20, and 5.5 min for liquid whole egg. Those corresponding to a m anosonication treatment (117 microns, 200 kPa, 40 degrees C) in both media were 0.73, 0.78, and 0.84 min, and 0.76, 0.84, and 1.4 min, respectively. W hen the amplitude of ultrasonic waves was increased linearly, the inactivat ion rate of manosonication increased exponentially. The inactivation rate a lso increased when pressure was raised. However, the magnitude of this incr ease was progressively smaller at higher pressures. The magnitude of the in fluence of the amplitude of ultrasonic waves and static pressure on the ina ctivation rate of manosonication was the same in the three serotypes invest igated. Whereas a heat treatment at 60 degrees C only attained a 1/2-log cy cle reduction in the number of Salmonella Senftenberg 775W survivors, a man othermosonication treatment (117 microns and 200 kPa) at this temperature a ttained a 3-log cycle reduction.