Survival of lactic acid bacteria in sea water

A feasibility study of lactic bacteria as potential probiotics in larval cultures of marine fish was performed by investigating the survival of five strains of lactic bacteria in sea water by readily standardised procedures at different temperatures and salinities. These conditions were chosen in such a way that their combinations define a complete first order factorial design. Depending on the strain and the ambient conditions, the survival adhered to first order kinetics in some cases and to the Gompertz equation in others. The half lives (t0.5) calculated from these models were subsequently introduced as responses to the factorial designs, estimating the coefficients of empirical equations which describe the group effect of temperature and salinity on t0.5. Simply additive effects were found in two cases, a negative first order interaction in another case, whilst another two required second order models.