Mild sonication intensity is an acoustic energy which involves the conversion of electrical signal into a physical vibration modifying the permeability of the cell plasma membrane. The objective of this study was to determine the effect of mild sonication intensities at different temperatures on growth, bile tolerance and protease activity of Streptococcus thermophilus . The treatments were four mild sonication intensities (8.07, 14.68, 19.83 and 23.55 W/cm 2 ) randomized at three different temperatures (4°C, 22°C and 40°C). The energy input (1500 J) was kept constant in all treatments. Control samples did not receive any sonication treatment. Growth and bile tolerance were determined every two hours for 12 h of incubation. Protease activity was determined at 0, 12 and 24 h. Mild sonication conditions included a) mild sonication intensities, b) temperatures and c) times, all three of which played a role in influencing the desirable attributes of Streptococcus salivarius ssp. thermophilus ST-M5. Of all the mild sonication intensities studied, 14.68 W/cm 2 had the best overall influence at certain time points for improving bile tolerance and growth at 4°C, growth at 22°C and bile tolerance and growth at 40°C of Streptococcus salivarius ssp. thermophilus ST-M5. Mild sonication intensity of 23.55 W/cm 2 had the overall best influence at certain time points for protease activity of Streptococcus salivarius ssp. thermophilus ST-M5 at 40°C. Streptococcus thermophilus ST-M5 pretreatment with some mild sonication conditions can be recommended for improvement of some of its characteristics.
P. Riesz and T. Kondo, “Free Radical Formation Induced by Ultrasound and Its Biological Implications,” Free Radical Biologyand and Medicine, Vol. 13, No. 3, 1992, pp. 247-270. doi:10.1016/0891-5849(92)90021-8
D. J. McClements, “Ultrasonic Characterization of Emulsions and Suspensions,” Advances in Colloid and Interface Science, Vol. 37, No. 1-2, 1991, pp. 33-72. doi:10.1016/0001-8686(91)80038-L
R. Karshafian, P. D. Bevan, R. William, S. Samac and P. N. Burns, “Sonoporation by Ultrasound-Activated Microbubble Contrast Agents: Effect of Acoustic Exposure Parameters on Cell Membrane Permeability and Cell Viability,” Ultrasound in Medicine and Biology, Vol. 35, No. 5, 2009, pp. 847-860. doi:10.1016/j.ultrasmedbio.2008.10.013
C. A. Dubbs, “Ultrasonic Effects on Isoenzymes,” Clinical Chemistry, Vol. 12, No. 4, 1996, pp. 181-186.
Y. Zhou and J. Shi, “Effects of Extracellular Calcium on Cell Membrane Resealing in Sonoporation,” Journal of Controlled Release, Vol. 126, No. 1, 2006, pp. 34-43.
W. G. Pitt and A. Ross, “Ultrasound Increases the Rate of Bacterial Cell Growth,” Biotechnology Progress, Vol. 19, No. 3, 2003, pp. 1038-1044. doi:10.1021/bp0340685
S. Drakopoulou, S. Terzakis, M. S. Fountoulakis, D. Mantzavinos and T. Manios, “Ultrasound-Induced Inactivation of Gram-Negative and Gram-Positive Bacteria in Secondary Treated Municipal Wastewater,” Ultrasonics Sonochemestry, Vol. 16, No. 5, 2009, pp. 629-634. doi:10.1016/j.ultsonch.2008.11.011
G. Scherba, R. M. Weigel and J. W. D. O’Brien, “Quantitative Assessment of the Germicidal Efficacy of Ultrasonic Energy,” Applied of Environmental Microbiology, Vol. 57, No. 7, 1991, pp. 2079-2084.
Global Information Inc., “The Vertical Research Portal,” 2011. http://www.giiresearch.com/report/pf45553-dairy.html
International Dairy Foods Association, “Dairy Facts,” 2010. http://www.idfa.org/files/_willow/products/481_DF2010.pdf
US Government Printing Office, “Code of Federal Regulations,” Title 21, Chapter 1, Subchapter B, Part 131, Subpart b, Section 131.200, 2010, pp. 346-347.
J. A. Kurmann, “Starters with Selected Intestinal Bacteria,” International Dairy Federation Bulletin, No. 227, 1998, pp. 41-45.
M. E. Kreft and P. Jelen, “Stability and Activity of β-Galactosidase in Sonicated Cultures of Lactobacillus delbrueckii ssp. bulgaricus 11842 as Affected by Temperature and Ionic Environments,” Journal of Food Science, Vol. 65, No. 8, 2000, pp. 1364-1368. doi:10.1111/j.1365-2621.2000.tb10613.x
D. Wang and M. Sakakibara, “Lactose Hydrolysis and β-Galactosidase Activity in Sonicated Fermentation with Lactobacillus Strains,” Ultrasonics Sonochemestry, Vol. 4, No. 3, 1997, pp. 255-261. doi:10.1016/S1350-4177(96)00042-9
Sonics Vibracell User Manual Sonicator, “High Intensity Ultrasonic Processor with Temperature Controller,” 2009. http://www.sonics.biz/lp-vibra.htm
D. J. McClement, “Advance in the Application of Ultrasound in Food Analysis and Processing,” Trends in Food Science and Technology, Vol. 6, No. 9, 1995, pp. 293-299. doi:10.1016/S0924-2244(00)89139-6
R. I. Dave and N. P. Shah, “Evaluation of Media for Selective Enumeration of Streptococcus thermophilus, Lactobacillus delbrueckii ssp. bulgaricus, Lactobacillus acidophilus, and Bifidobacteria,” Journal of Dairy Science, Vol. 79, No. 9, 1996, pp. 1529-1536. doi:10.3168/jds.S0022-0302(96)76513-X
M. Y. Lin and C. M. Young, “Folate Levels in Cultures of Lactic Acid Bacteria,” International Dairy Journal, Vol. 10, No. 5-6, 2000, pp. 409-413. doi:10.1016/S0958-6946(00)00056-X
C. P. Champagne, Y. Raymond, J. Gonthier and P. Audet, “Enumeration of the Contaminating Bacterial Microbiota in Unfermented Pasteurized Milks Enriched with Probiotic Bacteria,” Canadian Journal of Microbiology, Vol. 55, No. 4, 2009, pp. 410-418. doi:10.1139/W08-151
D. I. A. Pereira and G. R. Gibson, “Cholesterol Assimilation by Lactic Acid Bacteria and Bifidobacteria Isolated from the Human Gut,” Applied of Environmental Microbiology, Vol. 68, No. 9, 2002, pp. 4689-4693. doi:10.1128/AEM.68.9.4689-4693.2002
C. J. Oberg, B. C. Weimer, L. V. Moyes, R. J. Brown and G. H. Richardson, “Proteolytic Characterization of Lactobacillus delbrueckii ssp. bulgaricus Strains by the o -Phthaldialdehyde Test and Amino acid Analysis,” Journal of Dairy Science, Vol. 74, No. 2, 1991, pp. 398-403. doi:10.3168/jds.S0022-0302(91)78181-2
K. Aronsson, M. Lindgren, B. R. Johansson and U. Ronner, “Inactivation of Microorganisms Using Pulsed Electric Fields: The Influence of Process Parameters on Escherichia coli, Listeria innocua, Leuconostocmesenteroides and Saccharomyces cerevisiae,” Innovative Food Science Emerging Technology, Vol. 2, No. 1, 2001, pp. 41-54. doi:10.1016/S1466-8564(01)00021-2
M. T. Liong and N. P. Shah, “Acid and Bile Tolerance and Cholesterol Removal Ability of Lactobacilli Strains,” Journal of Dairy Science, Vol. 88, No. 1, 2005, pp. 55-66. doi:10.3168/jds.S0022-0302(05)72662-X
E. Simova, Z. Simov, D. Beshkova, G. Frengova, Z. Dimitrov and Z. Spasov, “Amino Acid Profiles of Lactic Acid Bacteria, Isolated from Kefir Grains and Kefir Starter Made from Them,” International Journal of Food Microbiology, Vol. 107, No. 2, 2006, pp. 112-123. doi:10.1016/j.ijfoodmicro.2005.08.020
H. Hülsheger, J. Potel and E. G. Niemann, “Electric Field Effects on Bacteria and Yeast Cells,” Radiation and Environmental Biophysics, Vol. 22, No. 2, 1983, pp. 149- 162. doi:10.1007/BF01338893
Y. Kobayashi, D. Sakai, T. Iwashina, S. Iwabuchi and J. Mochida, “Low-Intensity Pulsed Ultrasound Stimulates Cell Proliferation, Proteoglycan Synthesis and Expression of Growth Factor-Related Genes in Human Nucleus Pulposus Cell Line,” European Cells & Materials Journal, Vol. 17, 2009, pp. 15-22.
P. A. Clark and J. H. Martin, “Selection of Bifidobacteria for Use as Dietary Adjuncts in Cultured Dairy Foods: III. Tolerance to Simulated Bile Concentrations of Human Small Intestines,” Cultured Dairy Products Journal, Vol. 29, No. 3, 1994, pp. 18-21.
N. P. Shah and P. Jelen, “Survival of Lactic Acid Bacteria and Their Lactases under Acidic Conditions,” Journal of Food Science, Vol. 55, No. 2, 1990, pp. 506-509. doi:10.1111/j.1365-2621.1990.tb06797.x
M. Begley, C. Hill and C. G. M. Gahan, “Bile Salt Hydrolase Activity in Probiotics,” Applied and Environmental Microbiology, Vol. 72, No. 3, 2006, pp. 1729-1738. doi:10.1128/AEM.72.3.1729-1738.2006
S. Lick, K. Drescher and K. J. Heller, “Survival of Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the Terminal Ileum of Fistulated Gottingen Minipigs,” Applied of Environmental Microbiology, Vol. 67, No. 9, 2001, pp. 4137-4143. doi:10.1128/AEM.67.9.4137-4143.2001
D. Wang, M. Sakakibara, N. Kondoh and K.Suzuki, “Ultrasound-Enhanced Lactose Hydrolysis in Milk Fermentation with Lactobacillus bulgaricus,” Journal of Chemical Technology and Biotechnology, Vol. 65, No. 1, 1996, pp. 86-92.