Modelling the growth of Weissella cibaria as a function of fermentation conditions

To investigate the effect of pH, water activity (a(w)) and temperature on the growth of Weissella cibaria DBPZ1006, a lactic acid bacterium isolated from sourdoughs.

The kinetics of growth of W. cibaria DBPZ1006 was investigated during batch fermentations as a function of pH (4.0-8.0), a(w) (0.935-0.994) and temperature (10-45 degrees C) in a rich medium. The growth curve parameters (lag time, growth rate and asymptote) were estimated using the dynamic model of Baranyi and Roberts (1994. A dynamic approach to predicting bacterial growth in food. Int J Food Microbiol23, 277-294). The effect of pH, a(w) and temperature on maximum specific growth rate (micro(max)) were estimated by fitting a cardinal model. Micro(max) under optimal conditions (pH = 6.6, a(w) = 0.994, T = 36.3 degrees C) was estimated to be 0.93 h(-1). Minimum and maximum estimated pH and temperature for growth were 3.6 and 8.15, and 9.0 degrees C and 47.8 degrees C, respectively, while minimum a(w) was 0.918 (equivalent to 12.2% w/v NaCl).

Weissella cibaria DBPZ1006 is a fast-growing heterofermentative strain, which could be used in a mixed starter culture for making bread.

This is the first study reporting the modelling of the growth of W. cibaria, a species that is increasingly being used as a starter in sourdough and vegetable fermentations.