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Geobacillus spp. are thermophilic gram-positive endospore-forming bacteria capable of forming biofilms, and are encountered in a wide range of environments

Citation

Putri, TP and Dann, AL and Mellefont, LA and Williams, ML and Bowman, JP and Tamplin, ML and Ross, T, Geobacillus spp. are thermophilic gram-positive endospore-forming bacteria capable of forming biofilms, and are encountered in a wide range of environments, The Australian Society for Microbiology Annual Scientific Meeting, 7-10 July 2013, Adelaide, South Australia (2013) [Conference Extract]

Abstract

Geobacillus spp. are thermophilic Gram-positive endospore-forming bacteria capable of forming biofilms, and are encountered in a wide range of environments. In the food industry, biofilm formation and subsequent release of spores can limit production run times (between cleaning). Alternative means of controlling spore development in biofilms may extend production times, enhance productivity, improve product quality and increase revenue. Sixteen strains of Geobacillus spp, isolated from milk powders plants, were characterised. The growth rates in response to temperature were assessed by culture on agar media, and by optical density using a Bioscreen instrument. Based on its consistent growth responses compared to the other 15 strains, strain W14 was selected for further research. A temperature-controlled continuous flow-through device was designed, built and used in experiments intended to mimic the evaporator section of milk powder plants. Sterile milk, inoculated with various spore loads, was fed continuously into the flow-through device and viable counts and spores enumerated in the effluent over time. Six temperatures (45 - 74C), two flow rates and different modes of introduction of inocula were used to infer the development of biofilms from cell and spore counts in the milk leaving the chamber over time. The results showed growth rates were maximal over a broad temperature range (54 - 64C), and that generation times in this range were of the order 20 - 25 minutes. Viable cell numbers increased after approximately 3 - 6 hours at different temperatures, while spore counts began to increase after 6 - 8 hours, irrespective of the flow rate or method of inoculation.

Item Details

Item Type:Conference Extract
Keywords:thermophilic bacilli, milk powder, non-continuous flow through, spore cells.
Research Division:Engineering
Research Group:Food Sciences
Research Field:Food Packaging, Preservation and Safety
Objective Division:Manufacturing
Objective Group:Dairy Products
Objective Field:Processed Milk and Cream (incl. Powder, Evaporated and Condensed)
Author:Putri, TP (Miss Tuflikha Putri)
Author:Dann, AL (Dr Alison Dann)
Author:Mellefont, LA (Dr Lyndal Mellefont)
Author:Williams, ML (Ms Michelle Williams)
Author:Bowman, JP (Associate Professor John Bowman)
Author:Tamplin, ML (Professor Mark Tamplin)
Author:Ross, T (Associate Professor Tom Ross)
ID Code:84967
Year Published:2013
Deposited By:Tasmanian Institute of Agriculture
Deposited On:2013-06-07
Last Modified:2014-04-29
Downloads:0

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