title: Combined pressure-thermal inactivation effect on spores in lu-wei beef--a traditional Chinese meat product.
abstract: OBJECTIVE
  This study investigated the inactivation effect and kinetics of Bacillus coagulans and Geobacillus stearothermophilus spores suspended in lu-wei beef by combining high pressure (500 and 600 MPa) and moderate heat (70 and 80 °C or 80 and 90 °C).
  
  
  RESULTS
  During pressurization, the temperature of pressure-transmitting fluid was tested with a K-type thermocouple, and the number of surviving cells was determined by a plate count method. The pressure come-up time and corresponding inactivation of Bacillus coagulans and G. stearothermophilus spores were considered during the pressure-thermal treatment. For the two types of spores, the results showed a higher inactivation effect in phosphate buffer solution than that in lu-wei beef. Among the bacteria evaluated, G. stearothermophilus spores had a higher resistance than B. coagulans spores during the pressure-thermal processing. One linear model and two nonlinear models (i.e. the Weibull and log-logistic models) were fitted to the survivor data to obtain relevant kinetic parameters, and the performance of these models was compared. The results suggested that the survival curve of the spores could be accurately described utilizing the log-logistic model, which produced the best fit for all inactivation data.
  
  
  CONCLUSIONS
  The compression heating characteristics of different pressure-transmitting fluids should be considered when using high pressure to sterilize spores, particularly while the pressure is increasing. Spores can be inactivated by combining high pressure and moderate heat.
  
  
  CONCLUSIONS
  The study demonstrates the synergistic inactivation effect of moderate heat in combination with high pressure in real-life food. The use of mathematical models to predict the inactivation for spores could help the food industry further to develop optimum process conditions.
authors.affiliation: School of Chemistry and Chemical Engineering, Lingnan Normal University, ZhanJiang, Guangdong, China.
authors.forename: B-S
authors.initials: BS
authors.lastname: Wang
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, Guangdong, China.
authors.forename: B-S
authors.initials: BS
authors.lastname: Li
authors.affiliation: School of Chemistry and Chemical Engineering, Lingnan Normal University, ZhanJiang, Guangdong, China.
authors.forename: J-Z
authors.initials: JZ
authors.lastname: Du
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, Guangdong, China.
authors.forename: Q-X
authors.initials: QX
authors.lastname: Zeng
mesh_terms: D000818:Animals; D001407:Bacillus / Q000254:growth & development*; D002417:Cattle; D001411:Geobacillus stearothermophilus / Q000254:growth & development*; D006358:Hot Temperature; D006874:Hydrostatic Pressure; D007700:Kinetics; D008461:Meat Products / Q000382:microbiology*; D011312:Pressure; D000069466:Red Meat; D013171:Spores, Bacterial / Q000254:growth & development*; D013242:Sterilization / Q000379:methods*
keywords: beef; high-pressure technology; inactivation; moderate heat; spores