title: Sub-lethal heat treatment affects the tolerance of Cronobacter sakazakii BCRC 13988 to various organic acids, simulated gastric juice and bile solution.
abstract: Cronobacter spp., formerly Enterobacter sakazakii, are considered emerging opportunistic pathogens and the etiological agent of life-threatening bacterial infections in infants. In the present study, C. sakazakii BCRC 13988 was first subjected to sub-lethal heat treatment at 47°C for 15min. Survival rates of the heat-shocked and non-shocked C. sakazakii cells in phosphate buffer solution (PBS, pH 4.0) containing organic acids (e.g. acetic, propionic, citric, lactic or tartaric acid), simulated gastric juice (pH 2.0-4.0), and bile solution (0.5 and 2.0%) were examined. Results revealed that sub-lethal heat treatment enhanced the test organism's tolerance to organic acids, although the extent of increased acid tolerance varied with the organic acid examined. Compared with the control cells, heat-shocked C. sakazakii cells after 120-min of exposure, exhibited the largest increase in tolerance in the lactic acid-containing PBS. Furthermore, although heat shock did not affect the behavior of C. sakazakii in bile solution, it increased the test organism's survival when exposed to simulated gastric juice with a pH of 3.0-4.0.
authors.affiliation: Graduate Institute of Food Science and Technology, National Taiwan University, Taipei, Taiwan.
authors.forename: Wan-Ling
authors.initials: WL
authors.lastname: Hsiao
authors.forename: Wei-Li
authors.initials: WL
authors.lastname: Ho
authors.forename: Cheng-Chun
authors.initials: CC
authors.lastname: Chou
mesh_terms: D001647:Bile Acids and Salts / Q000633:toxicity; D002264:Carboxylic Acids / Q000633:toxicity; D044083:Cronobacter sakazakii / Q000502:physiology*; D005750:Gastric Juice; D018869:Heat-Shock Response; D006358:Hot Temperature; D050296:Microbial Viability; D012996:Solutions
chemical_list: D001647:Bile Acids and Salts; D002264:Carboxylic Acids; D012996:Solutions