Evaluation and bacterial populations associated with fresh mushrooms (agaricus bisporus)

Stephanie Doores, Michael Kramer, Robert Beelman

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Doores, Stephanie, Kramer, Michael, and Beelman, Robert. 1986. Evaluation of bacterial populations associated with fresh mushrooms (Agaricus bisporus) Proc. Int. Symp. Tech Aspects Cult. Edible Fungi Total aerobic bacterial counts on mushrooms were determined for the first six flushes of the crop cycle and the casing material and water were sampled at selected intervals. Total bacterial numbers ranged from 2. 1 to 16 × 106 CFU/g; numbers were relatively constant through the fifth flush of the crop cycle and decreased slightly by flush 6. Counts from casing material were considerably higher, between 1. 7 and 2. 9 × 108 CFU/g and also were relatively constant over the cycle. Bacterial counts from tap water were lower and did not appear to contribute to overall microbial populations. The majority (54. 0%) of bacteria isolated from the individual flushes were identified as fluorescent pseudomonads with flavobacteria comprising the second largest group (10. 0%). The proportions of these two organisms remained relatively constant; however, the pseudomonads decreased between the fifth and sixth flush while the flavobacteria increased. Bacterial populations during postharvest storage at 13°C increased from an initial load of 107 CFU/g to almost 1011 CFU/g. The same two groups predominated but the proportion of flavobacteria increased during later storage. A third group of pseudomonads having mucoidal colonies appeared during storage in a biphasic manner. Deterioration of mushroom quality as indicated by maturity and color measurement appeared concomitant with bacterial growth indicating that darkening is related to increased bacterial numbers. However, phytopathogenic strains of microorganisms responsible for blotch occurred in very low numbers during storage.

Original languageEnglish (US)
Pages (from-to)283-294
Number of pages12
JournalDevelopments in Crop Science
Issue numberC
StatePublished - 1987

All Science Journal Classification (ASJC) codes

  • Agronomy and Crop Science


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