Growth Inhibition of Common Food Spoilage and Pathogenic Microorganisms in the Presence of Brown Seaweed Extracts

The possibility of using extracts from brown seaweed, Himanthalia elongata, as a natural antimicrobial agent for food preservation is presented. The effect of different concentrations of seaweed extract on the growth kinetics of four common food spoilage (Pseudomonas aeruginosa and Enterococcus faecalis) and food pathogenic microorganisms (Listeria monocytogenes and Salmonella abony) was examined. Seaweed extract at a concentration of 6% inhibited the growth of all four of the studied organisms. Lower concentrations of seaweed extract prolonged the lag phase and reduced both the exponential growth rate and final population densities of the culture. Suitability of three kinetic models, Baranyi–Roberts, modified Gompertz and logistic, for describing the growth/survival of organisms in the presence of different concentrations of the extract, was evaluated. Root mean square error (RMSE) and correlation coefficient (R ²) were used to evaluate the model performance. The R ² value was greater than 0.95 for most of the cases indicating that the models could provide a good fitting to the experimental data. The RMSE and residual sum of squares were very low for all the three models, and no significant difference was observed in the goodness of fit between the three models as indicated by the F test.