Microbial populations associated with commercially produced South African sorghum beer as determined by conventional and Petrifilm™ plating
| Autor: | Alexander von Holy, Tracey-Lee Pattison, Ifigenia Geornaras |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Quality Control
Gram-negative bacteria Aerobic bacteria Colony Count Microbial Bacillus Microbiology Petrifilm Micrococcus South Africa chemistry.chemical_compound Yeasts Gram-Negative Bacteria Food-Processing Industry Food science biology Beer General Medicine MRS agar Hydrogen-Ion Concentration biology.organism_classification Yeast Lactic acid Lactobacillus chemistry Fermentation Food Microbiology Edible Grain Nutrient agar Bacteria Food Science |
| Zdroj: | International Journal of Food Microbiology. 43:115-122 |
| ISSN: | 0168-1605 |
| DOI: | 10.1016/s0168-1605(98)00103-2 |
| Popis: | Microbial populations of 46 commercially produced sorghum beer samples from retail outlets in Johannesburg, South Africa, were enumerated and characterized. Aerobic plate counts, lactic acid bacteria counts and yeast counts were performed by conventional and Petrifilm™ plating. Conventional methods yielded yeast counts of 7.84 log CFU/ml, lactic acid bacteria counts of 6.44 log CFU/ml and aerobic plate counts of 5.96 log CFU/ml. In comparison, Petrifilm™ counts were 7.85 log CFU/ml for yeasts, 5.31 log CFU/ml for lactic acid bacteria and 5.34 log CFU/ml for aerobic bacteria. Characterization of 419 predominant bacterial isolates from Standard One Nutrient Agar, MRS Agar and corresponding Petrifilm™ plates yielded 88.0% lactic acid bacteria, 8.4% Bacillus species, 2.9% Micrococcus species and 0.7% Gram negative bacteria. Composition of predominant lactic acid bacteria populations from Standard One Nutrient Agar and both types of Petrifilm™ plates showed marginal differences. Increased proportions of heterofermentative lactic acid bacteria were, however, isolated from conventional MRS Agar compared to the modified Petrifilm™ product which represented the equivalent to MRS Agar. |
| Databáze: | OpenAIRE |
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