title: Impact of indigenous microorganisms on Escherichia coli O157:H7 growth in cured compost.
abstract: Both autoclaving and dry-heat treatments were applied to dairy manure-based compost to achieve target populations of indigenous microorganisms. A 3 strain-mixture of Escherichia coli O157:H7 of ca. 2 log CFU/g was inoculated into acclimated autoclaved compost (AAC) and dry heat-treated compost (DHTC) with different moistures, and stored at 8, 22, or 30 °C. Only selected groups of microorganisms grew in AAC during acclimation, whereas the relative ratio of each group of microorganisms was maintained in DHTC after heat treatment. E. coli O157:H7 grew more in AAC than DHTC in the presence of same level of indigenous mesophiles. However, control compost (no heat treatment) did not support E. coli O157:H7 growth. Our results revealed that both the type and population of indigenous microorganisms is critical for suppressing E. coli O157:H7 growth in compost, and dry-heat treatment can result in a compost product which resembles cured compost with different levels of indigenous microorganisms.
authors.affiliation: Department of Food, Nutrition, and Packaging Sciences, Clemson University, Clemson, SC 29634-0316, USA.
authors.forename: Jinkyung
authors.initials: J
authors.lastname: Kim
authors.forename: Cortney M
authors.initials: CM
authors.lastname: Miller
authors.forename: Marion W
authors.initials: MW
authors.lastname: Shepherd
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Liu
authors.forename: Xiuping
authors.initials: X
authors.lastname: Jiang
mesh_terms: D001483:Base Sequence; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D019453:Escherichia coli O157 / Q000254:growth & development*; D006358:Hot Temperature; D016133:Polymerase Chain Reaction; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012987:Soil
chemical_list: D017931:DNA Primers; D012336:RNA, Ribosomal, 16S; D012987:Soil