Thermal Resistance Parameters for Shiga Toxin―Producing Escherichia coli in Apple Juice

• Published in: Journal of food protection 2011-08, Vol.74 (8), p.1231-1237
• Main Authors: ENACHE, Elena, MATHUSA, Emily C, ELLIOTT, Philip H, GLENN BLACK, D, YUHUAN CHEN, SCOTT, Virginia N, SCHAFFNER, Donald W
• Format: Article
• Language: English
• Subjects: Apples; Beverages - microbiology; Biological and medical sciences; Consumer Product Safety; E coli; Epidemics; Escherichia coli; Escherichia coli O157 - growth & development; Food Contamination - analysis; Food industries; Food Microbiology; Food safety; Fruit and vegetable industries; Fruit juices; Fundamental and applied biological sciences. Psychology; Heat resistance; Hot Temperature; Humans; Infections; Malus; Serotyping; Shiga Toxin - analysis; Shiga Toxin - metabolism; Shiga-Toxigenic Escherichia coli - growth & development; Shiga-Toxigenic Escherichia coli - metabolism; Toxins
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028x.jfp-10-488

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).