Department of Food Science, Stellenbosch University, Stellenbosch, South Africa; Department of Biotechnology, University of the Western Cape, Bellville, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
Witthuhn, R.C., Department of Food Science, Stellenbosch University, Stellenbosch, South Africa, Department of Food Science, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa; Duvenage, W., Department of Food Science, Stellenbosch University, Stellenbosch, South Africa; Gouws, P.A., Department of Biotechnology, University of the Western Cape, Bellville, South Africa
Aims: Five different isolation media, namely potato dextrose agar (PDA), orange serum agar (OSA), K agar, yeast-starch-glucose agar and Bacillus acidocaldarius medium were evaluated for the recovery of Alicyclobacillus spp. from inoculated diluted and undiluted fruit-juice concentrates. Methods and Results: Plates of PDA (pH 3.7), spread with vegetative cells (3.9 × 106 CFU ml-1) of Alicyclobacillus acidoterrestris from single-strength pear juice, recovered 2.9 × 106CFU ml -1 after 5 days at 50°C (74% recovery). The recovery of endospores from single-strength pear juice, after a heat treatment at 80°C for 10 min, was higher on spread plates of OSA (pH 5.5) at 50°C for 5 days (97% recovery). Conclusions: PDA (pH 3.7) and OSA (pH 5.5) at 50°C for 3-5 days recovered the highest numbers of vegative cells and endospores of Alicyclobacillus spp. from sterilized fruit juices and concentrates. Significance and Impact of the Study: The most appropriate synthetic media for the recovery of Alicyclobacillus species from inoculated fruit juices and concentrates are shown. © 2007 The Authors.
Bacteria; Cells; Fruit juices; Glucose; Heat treatment; pH effects; agar; bacterium; dilution; glucose; inoculation; sporulation; yeast; Alicyclobacillus; article; bacterial endospore; bacterial growth; bacterial strain; culture medium; heat treatment; nonhuman; vegetative growth; Agar; Bacteriological Techniques; Beverages; Culture Media; Gram-Positive Endospore-Forming Bacteria; Hydrogen-Ion Concentration; Species Specificity; Temperature; Vitis; Alicyclobacillus; Alicyclobacillus acidocaldarius; Alicyclobacillus acidoterrestris; Pyrus; Solanum tuberosum