Fate of Staphylococcus aureus in Cheese Treated by Ultrahigh Pressure Homogenization and High Hydrostatic Pressure

Sensitivity of Staphylococcus aureus and Lactobacillus helveticus in ovine milk subjected to high hydrostatic pressure.

Ovine milk, standardized to 6% fat, was inoculated with Staphylococcus aureus CECT 534 and Lactobacillus helveticus CECT 414 at a concentration of 10(7) cfu/ml and treated by high hydrostatic pressure. Treatments consisted of combinations of pressure (200, 300, 400, 450, and 500 MPa), temperature (2, 10, 25, and 50 degrees C), and time (5, 10, and 15 min). Staphylococcus aureus was highly resis...

Biological approach to modeling of Staphylococcus aureus high-hydrostatic-pressure inactivation kinetics.

Graphs for survival under high hydrostatic pressure (450 MPa; 25°C; citrate-phosphate buffer, pH 7.0) of stationary-growth-phase cells of eight Staphylococcus aureus strains were found to be nonlinear. The strains could be classified into two groups on the basis of the shoulder length. Some of them showed long shoulders of up to 20 min at 450 MPa, while others had shoulders of <3.5 min. All str...

High hydrostatic pressure

The use of high pressure processing (HPP) in the food industry was developed as an alternative to common thermal processes, such as pasteurization and sterilization, to produce a microbiologically safe food while avoiding and reducing undesirable changes in sensory, physiochemical and nutritional properties of foods. The use of high pressure at high temperatures as a tool for sterilization (hig...

Microbial Cell Disruption by High-Pressure Homogenization

Effect of pressure-induced changes in the ionization equilibria of buffers on inactivation of Escherichia coli and Staphylococcus aureus by high hydrostatic pressure.

Survival rates of Escherichia coli and Staphylococcus aureus after high-pressure treatment in buffers that had large or small reaction volumes (ΔV°), and which therefore underwent large or small changes in pH under pressure, were compared. At a low buffer concentration of 0.005 M, survival was, as expected, better in MOPS (morpholinepropanesulfonic acid), HEPES, and Tris, whose ΔV° values are a...