Methods of Examining Damp Grain at Harvest and After Sealed and Open Storage: Changes in the Microflora of Damp Grain during Sealed Storage

Abstract

Summary. Methods are described for enumerating the micro‐organisms occurring on damp grain (18–35% moisture content) after harvesting and after sealed and open storage. The microflora of 41 samples of damp grain at harvesting and 137 samples after sealed storage on farms have been examined. The latter included 25 samples from experimental storage, including polythene bags, and 51 samples from stores where spoilage had occurred or advice was sought. A remarkably consistent population level of bacteria, moulds and yeasts was found on damp grain at harvesting. This information was used as a convenient basis for comparisons with results from grain after storage. Bacteria were initially present at 1–10 × 106/g, but the level generally diminished during anaerobic storage. Also coli‐aerogenes bacteria died out but lactobacilli increased. Strict anaerobes (Clostridium spp.) did not develop. Moulds originally present in small numbers normally decreased but while total yeasts often remained at the ingoing number, there was a change from non‐myceliated to myceliated species, numbers of which sometimes increased further. If thermophilic yeasts and moulds or Streptomycetaceae were present in large numbers, the grain had been subjected to aeration and had heated. Sometimes mould growth appeared to cause binding of the grain, but in other instances myceliated yeasts were implicated.

Antibiotic amendment for suppression of indigenous microflora in feed sources for an Escherichia coli auxotroph lysine assay

“…To prevent feed fungal growth, the antifungal agent cycloheximide was included. It has been used to inhibit fungal populations in moist, stored grain in order to enumerate bacterial populations successfully ( Nichols & Leaver 1966; Clarke & Hill 1981) and is effective in suppressing indigenous feed fungal colonies without inhibiting the growth of E. coli ( Ha et al . 1995a ).…”

The microbiology of moist barley storage in unsealed silos

“…and yeasts appeared most frequently on plates. Colonies of Fusarium and Alternaria were not common, although these were frequently found by Nichols & Leaver (1966) and by Mulinge & Chesters (197oa). Thermoactinomyces vulgaris Tsiklinsky and Streptomyces spp.…”

“…Thermoactinomyces vulgaris Tsiklinsky and Streptomyces spp. grew more often on plates from the Andersen sampler (up to 109/g) than on dilution plates (up to Io/g) (Nichols & Leaver, 1966 Two samples of grass used for capping contained 5 and I Z x 106 sporeslg. Cladosporium spp.…”

Yeasts in an industrial malting ecosystem

“…Pigmented-yeasts may be responsible for discoloration of barley kernels and of grain products [37]. Yeasts also caused bridging of damp kernels during post-harvest storage in silos [48]. This extensive formation of yeast biomass around the kernels is also very likely to aVect grain physiology during malting if uncontrolled yeast growth occurs during processing.…”