Thermal resistance parameters for shiga toxin - Producing Escherichia coli in apple juice

Elena Enache, Emily C. Mathusa, Philip H. Elliott, D. Glenn Black, Yuhuan Chen, Virginia N. Scott, Donald W. Schaffner

Research output: Contribution to journalArticle

25 Scopus citations

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).

Original languageEnglish (US)
Pages (from-to)1231-1237
Number of pages7
JournalJournal of food protection
Volume74
Issue number8
DOIs
StatePublished - Aug 1 2011

All Science Journal Classification (ASJC) codes

  • Food Science
  • Microbiology

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