Preservation of High-Moisture Corn: A Microbiological Evaluation

Abstract

Ammonia, ammonium isobutyrate, isobutyric acid, and propionic-acetic acid at concentrations of .5%, 1.75%, 1.5%, and 1.2%, respectively, were applied to comparable 52.8m3 lots of freshly harvested yellow dent corn having a moisture content of 27%. Treated corn was stored in partially open wooden bins. Harvestore® and barrell storage of untreated corn were included as controls. Temperature and microbiological changes were evaluated throughout 6 mo of storage. As the corn came from the field, log counts of 6.3, 5.8, 5.3, and 3.0 per g were determined for bacteria, molds, yeasts, and actinomycetes, respectively. All chemicals immediately reduced bacterial and actinomycete counts and eliminated molds and yeasts. All treatments after approximately 30 days’ storage had secondary fungal growth. Scopulariopsis brevicaulis predominated on ammonia-treated corn; Mucorales, and species of Monascus, Peniaillium, Fusarium, and Aspergillus flavus, as well as A. fumigatus, were in ammonium isobutyrate-treated corn. A. flavus was the predominant mold infecting isobutyric acid and propionic-acetic acid treated corn late in storage.