Effect of High Intensity Ultrasound Treatment on the Growth of Food Spoilage Bacteria

Zoran Herceg1*, Ksenija Markov1, Brankica Sobota Šalamon1, Anet Režek Jambrak1, Tomislava Vukušić1 and Janko Kaliterna2

Faculty of Food Technology and Biotechnology, University of Zagreb, Pierottijeva 6, HR-10000 Zagreb, Croatia 

2Kraš d.d., Ravnice 48, HR-10000 Zagreb, Croatia

Article history:

Received October 11, 2012
Accepted May 7, 2013

Key words:

high intensity ultrasound, bacteria, inactivation, experimental design, optimization


The aim of this study is to determine the effect of high intensity ultrasound (amplitude, temperature and treatment time) on the inactivation of food spoilage bacteria Escherichia coli 3014, Staphylococcus aureus 3048, Salmonella sp. 3064, Listeria monocytogenes ATCC 23074 and Bacillus cereus 30. The model suspensions of bacteria were treated with 12.7-mm ultrasonic probe operated at 600 W nominal power (ultrasonic treatment implemented at 20 kHz) and at amplitudes of 60, 90 and 120 μm. Also, treatment time of 3, 6 and 9 min and temperature of 20, 40 and 60 °C were used. The results were statistically processed with STATGRAPHICS Centurion computer program and response surface methodology. All three parameters studied seem to substantially affect the inactivation of bacteria in pure culture. The results also indicate increased inactivation of microorganisms under longer period of treatments, particularly in combination with higher temperature and/or amplitude. After ultrasonic treatment at 60 °C, 9 min and 120 mm, the viability of cells was not confirmed for Escherichia coli 3014, Staphylococcus aureus 3048, Salmonella sp. 3064 and Listeria monocytogenes ATCC 23074. Under the mentioned conditions the highest inactivation (3.48 log CFU/mL) of Bacillus cereus 30 was obtained.

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