High Pressure Processing

The quest to attain Industrial scale of a high-pressure (HP) treated fresh cheese necessitated the present study. HP treatment was applied on rennet-coagulated soft Scottish cheese and its effects on the microbiological quality and physico-chemical properties were investigated. HP treatment influenced significantly the colour, fat, moisture, lipid oxidation, hardness, and adhesiveness of the fresh cheese. Moisture released from the HP treated fresh cheese showed the potential to carry along other molecular constituents such as fractions of protein under suitable conditions of pressure. Microbiological quality of HP treated fresh cheese was examined in terms of shelf-life and HP's influence on microbial population compared to non-treated cheese. Estimated shelf life of 17 days was extended to 31 days at highest pressures due to significant bacterial count reductions obtained.Gram-positive cocci and rods as well as Gram-negative rods were obtained during spoilage period of the fresh cheese whereas pressures up to 291 MPa resulted in sufficient bacterial inactivation to influence its recovery.