Mild pressure treatments applied to Pediococcus Acidilactici HA-6111-2 at exponential growth phase

Pediococcus acidilactici HA-6111-2 and its bacteriocin (bacHA- 6111-2) are promising natural food preservatives to control growth of Listeria in several food products (e.g., fermented meat sausages). The effect of mild pressure treatments in the survival of P. acidilactici HA- 6111-2 at late exponential growth phase was evaluated. The production of bacHA-6111-2 per cell in the late exponential phase was also determined. At the applied pressures, the cells in the exponential phase revealed to be more barosensitive than the cells in the earlier stationary phase of growth. The antimicrobial activity of the bacteriocin in both control and pressure treated cells at the exponential phase presented no changes regarding the pattern often reported for pediocins: the production level reached a maximum value at a given time, followed by a sudden declination. However, when cells were pressurized at 200 MPa, the bacteriocin production might be triggered earlier.