Influence of thermosonication on Geobacillus stearothermophilus inactivation in skim milk

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• 作者：Nicola F. Beatty ; Marie K. Walsh ; ^{marie.walsh@usu.edu" class="auth_mail" title="E-mail the corresponding author}
• 刊名：International Dairy Journal
• 出版年：2016
• 出版时间：October 2016
• 年：2016
• 卷：61
• 期：Complete
• 页码：10-17
• 全文大小：916 K

文摘

The influence of high intensity ultrasound coupled with thermoprocessing on the inactivation of Geobacillus stearothermophilus vegetative cells and spores in skim milk powder was explored using response surface methodology and two polynomial models were developed. Optimization of cell reduction (4.8 log) was found to be at 19.75% total solids (TS), 45 °C, and 30 s, while optimization of spore reduction (0.45 log) was found to be at 31.5% TS, 67.5 °C, and 17.5 s. Model verification experiments were performed using common milk powder processing conditions. Results showed the inactivation of cells and spores to be most effective before (9.2% TS, 75 °C, and 10 s) and after (50% TS, 60 °C, and 10 s) the evaporator during milk powder processing and may produce an additive effect in microbial reduction when the two locations are combined, resulting in a 5.8 log reduction for vegetative cells and 0.51 log reduction for spores.