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

Aims: To investigate the effect of pH, water activity (aw) and temperature on the growth of Weissella cibaria DBPZ1006, a lactic acid bacterium isolated from sourdoughs. Methods and Results: The kinetics of growth of W. cibaria DBPZ1006 was investigated during batch fermentations as a function of pH (4Æ0–8Æ0), aw (0Æ935–0Æ994) and temperature (10–45°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 predic- ting bacterial growth in food. Int J Food Microbiol 23, 277–294). The effect of pH, aw and temperature on maximum specific growth rate (lmax) were esti- mated by fitting a cardinal model. lmax under optimal conditions (pH = 6Æ6, aw = 0Æ994, T = 36Æ3°C) was estimated to be 0Æ93 h)1. Minimum and maxi- mum estimated pH and temperature for growth were 3Æ6 and 8Æ15, and 9Æ0°C and 47Æ8°C, respectively, while minimum aw was 0Æ918 (equivalent to 12Æ2% w ⁄ v NaCl). Conclusions: Weissella cibaria DBPZ1006 is a fast-growing heterofermentative strain, which could be used in a mixed starter culture for making bread. Significance and Impact of the Study: 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.