The growth and potential attachment of Listeria monocytogenes to cast iron in drains was investigated in this study. L. monocytogenes was grown in rich and dilute nutritive media in free-standing cast iron drains. The pH in the drain was adjusted over the growth period to pH 4.5, 7.0, and 9.0. L. monocytogenes was found to survive pH adjustments in drains for 28 d. Scanning electron microscopy (SEM) was used to investigate the attachment of L. monocytogenes to cast iron chips. SEM observation showed L. monocytogenes cells apparently attached to the iron surface of the chip. Listeria does not appear to attach as readily to cast iron as to stainless steel surfaces.

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Author notes

1Published as paper No. 18766 of the contribution series of the Minnesota Agricultural Experiment Station based on research conducted under Project 18-56, supported by Hatch funds.