Survival of foodborne pathogenic bacteria in table olive brines

Fermented or acidified vegetable foods are considered microbiologically safe although the survival of certain pathogens has occasionally been reported in these products. The aim of this research was to investigate the fate of Escherichia coli, Salmonella enterica, Listeria monocytogenes and Staphylococcus aureus when they were added to different industrial olive brines, as well as to correlate their survival with the presence of phenolic and oleosidic substances. Brines of different cultivars prepared following the Spanish-style method or preserved in acidified brine were inoculated with a cocktail of four strains of each species. The evolution of their populations was analyzed by cultural methods when the brines were kept at 4 °C or room temperature and in aerobiosis or anaerobiosis. All the pathogens investigated died off but their death rate was variable depending on the composition of the brines in phenolic compounds, temperature and oxygen availability. The time needed to reduce the inoculated pathogen populations by 5 log oscillated between less than 5 min and up to 17 days in the least deleterious conditions.