Authors
Abstract(s)
Following consumers’ demand for safe and nutritious foods without chemical
preservatives, food industries are looking for new preservation solutions. Among
these, high pressure processing (HPP) and biopreservation are non-thermal
technologies showing significant potential for effective food preservation without
altering nutritional value and organoleptic properties of food. It has been shown that
biopreservation using lactic acid bacteria (LAB) and/or their bacteriocins inhibit
pathogens, but at present time there were no studies about the influence of HPP on the
antimicrobial activity of LAB. The objectives of this study were to evaluate the
effects of HPP on the antimicrobial activity of a bacteriocinogenic strain of LAB
(Pediococcus acidilactici HA-6111-2) and its bacteriocin and to evaluate the
effectiveness of HPP combined with P. acidilactici for inactivation of Listeria
innocua N27 (used as a surrogate for Listeria monocytogenes) in RTE sliced meat
sausages. Pediococcus acidilactici was exposed to pressures between 200 and 500
MPa at 25 °C for 5 min and subsequent freezing at -20 °C. A pressure of 200 MPa did
not affect bacteriocin production, whereas 300 MPa caused a two times reduction in
antimicrobial activity of P. acidilactici. Further increase of pressures (400 MPa and
500 MPa) reduced bacteriocin activity 4 to 8 times. High hydrostatic pressures and
freezing postponed bacteriocin production. Bacteriocin production began 9 h earlier
when the samples were not frozen. The antimicrobial activity of bacteriocins
produced by P. acidilactici was reduced after pressurization. The synergistic effect of
high hydrostatic pressure (300 MPa, 5 min, 25 °C) combined with P. acidilactici
against L. innocua in ready to eat sliced meat sausages during storage at 4 °C for 60
days was assessed. Application of pressure and P. acidilactici resulted in 2 log
inactivation of L. innocua. The food matrix had a protective effect on pressure
inactivation of L. innocua. The results of this work clearly illustrate the potential of
pressure combined with bacteriocinogenic cultures as an alternative for chemical
preservation. Yet, synergistic effect of high pressure processing and P. acidilactici
requires further investigation on more suitable foods.