Survival of foodborne pathogens in natural cracked olive brines.

Abstract This work reports the survival (challenge tests) of foodborne pathogen species ( Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, and Salmonella enterica ) in Alorena de Malaga table olive brines. The inhibitions were fit using a log-linear model with tail implemented in GInaFIT excel software. The olive brine had a considerable inhibitory effect on the pathogens. The residual (final) populations ( Fp ) after 24 h was below detection limit ( 10  cfu/mL) for all species assayed. The maximum death rate ( k max ) was 9.98, 51.37, 38.35 and 53.01 h −1 , while the time for 4 log 10 reductions ( 4D r ) was 0.96, 0.36, 0.36 and 0.24 h for E. coli, S. aureus, L. monocytogenes and S. enterica, respectively. Brine dilutions increased Fp and 4Dr , while decreased k max . A cluster analysis showed that E. coli had an overall quite different behaviour being the most resistant species, but the others bacteria behaved similarly, especially S. aureus and S. enterica . Partial Least Squares regression showed that the most influential phenols on microbial survival were EDA (dialdehydic form of decarboxymethyl elenolic acid), HyEDA (EDA linked to hydroxytyrosol), hydroxytyrosol 4-glucoside, tyrosol, and oleoside 11-methyl ester. Results confirm the adverse habitats of table olives for foodborne pathogenic microorganisms.