Effect of non-thermal processing by High Hydrostatic Pressure on the survival of probiotic microorganisms: Study on Bifidobacteria spp.

High Hydrostatic Pressure (HP) processing has been suggested as an alternative method to improve textural attributes of dairy products. Since, the global market seeks improved functional foods, it is important to investigate whether HP processing can be applied to fermented dairy probiotic products. The inactivation kinetics of Bifidobacterium spp. in a model system of acid pH value under high pressure (100-400 MPa) combined with moderate temperature (20-35 degrees C) was investigated. Bifidobacterium spp. inactivation followed first order kinetics at all pressure temperature combinations used. Pressure and temperature were found to act synergistically on the viability loss of the bacterium. The corresponding z(T) and z(P) values of inactivation were also estimated and, values of 41.5 degrees C and 93.5 MPa at reference pressure of 200 MPa and reference temperature of 25 degrees C were estimated, respectively. HP treatment of 200 MPa at 20-25 degrees C for 10-15 min, recommended for textural modification, is not detrimental to the viability of the studied probiotic culture and would be suitable for respective fermented probiotic products. (C) 2011 Elsevier Ltd. All rights reserved.