SURVIVAL OF ACID ADAPTED AND NON-ADAPTED STATIONARY PHASE ESCHERICHIA COLI O157:H7, SALMONELLA TYPHIMURIUM AND LISTERIA MONOCYTOGENES IN POMEGRANATE JUICE

Abstract

The purpose of this study was to evaluate the survival of acid adapted and non-adapted stationary phase Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes in pomegranate juice at refrigeration and room temperatures. Inoculated juice samples were stored at 4 and 24 ± 2°C. Population of pathogens were enumerated for up to 28 days. Reduction rates, time required for one log reduction, of tested microorganisms were calculated. Enrichment was negative for E. coli O157:H7 after a week at all tested conditions. At refrigeration temperature, acid adapted S. Typhimurium and L. monocytogenes survived one week longer than non-adapted cells. At room temperature, S. Typhimurium population decreased up to 7 log CFU/ml in 28 days; L. monocytogenes survived less than 12 h. Rates of reduction (days) ranged between 0.06 and 4.29 for all tested pathogens (P<0.05). Tested pathogens can survive in contaminated pomegranate juice until consumption to cause foodborne illness.