Modelling growth and bacteriocin production by Lactobacillus curvatus LTH 1174 in response to temperature and pH values used for European sausage fermentation processes.

Lactobacillus curvatus LTH 1174, a strain isolated from fermented sausage, produces the antilisterial bacteriocin curvacin A. Its biokinetics of cell growth and bacteriocin production as a function of temperature (20-38 degrees C) and pH (4.8-7.0) were investigated in vitro during laboratory fermentations using de Man, Rogosa and Sharpe (MRS) medium. A predictive, successfully validated model was set up to describe the influence of temperature and pH on the microbial behavior. Both cell growth and bacteriocin activity were influenced by changes in temperature and pH. The optimum temperature value for cell growth, 34.5 degrees C, did not correspond with the optimum temperature for curvacin A production (20-27 degrees C). Interestingly, the pH range for growth and curvacin A production was broad. Thus, Lb. curvatus LTH 1174 seems to be a promising bacteriocin-producing strain for use in European sausage fermentations that are performed at temperatures near 25 degrees C.