title: Thermal resistance parameters for Shiga toxin-producing Escherichia coli in apple juice.
abstract: The purpose of the present study was to determine the heat resistance of six non-O157 Shiga toxin-producing Escherichia coli (STEC) serotypes in comparison to E. coli O157:H7 in single-strength apple juice without pulp. The thermal parameters for stationary-phase and acid-adapted cells of E. coli strains from serogroups O26, O45, O103, O111, O121, O145, and O157:H7 were determined by using an immersed coil apparatus. The most heat-sensitive serotype in the present study was O26. Stationary-phase cells for serotypes O145, O121, and O45 had the highest D(56°C)-value among the six non-O157 serotypes studied, although all were significantly lower (P < 0.05) than that of E. coli O157:H7. At 60°C E. coli O157:H7 and O103 demonstrated the highest D-values (1.37 ± 0.23 and 1.07 ± 0.03 min, respectively). The D(62°C) for the most heat-resistant strain belonging to the serotype O145 was similar (P > 0.05) to that for the most resistant O157:H7 strain (0.61 ± 0.17 and 0.60 ± 0.09 min, respectively). The heat resistance for stationary-phase cells was generally equal to or higher than that of acid-adapted counterparts. Although E. coli O157:H7 revealed D-values similar to or higher than the individual six non-O157 STEC serotypes in apple juice, the z-values for most non-O157 STEC tested strains were greater than those of E. coli O157:H7. When data were used to calculate heat resistance parameters at a temperature recommended in U.S. Food and Drug Administration guidance to industry, the D(71.1°C) for E. coli O157:H7 and non-O157 STEC serotypes were not significantly different (P > 0.05).
authors.affiliation: Grocery Manufacturers Association, Washington, D.C. 20005, USA. eenache@gmaonline.org
authors.forename: Elena
authors.initials: E
authors.lastname: Enache
authors.forename: Emily C
authors.initials: EC
authors.lastname: Mathusa
authors.forename: Philip H
authors.initials: PH
authors.lastname: Elliott
authors.forename: D Glenn
authors.initials: DG
authors.lastname: Black
authors.forename: Yuhuan
authors.initials: Y
authors.lastname: Chen
authors.forename: Virginia N
authors.initials: VN
authors.lastname: Scott
authors.forename: Donald W
authors.initials: DW
authors.lastname: Schaffner
mesh_terms: D001628:Beverages / Q000382:microbiology*; D003257:Consumer Product Safety; D019453:Escherichia coli O157 / Q000254:growth & development; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006358:Hot Temperature; D006801:Humans; D027845:Malus; D012703:Serotyping; D022621:Shiga Toxin / Q000032:analysis / Q000378:metabolism; D054323:Shiga-Toxigenic Escherichia coli / Q000254:growth & development* / Q000378:metabolism
chemical_list: D022621:Shiga Toxin