The effectiveness of an adsorption filter in retaining bacteria present in milk was examined. Skim milk and whole milk (100ml) were separately filtered through a 47mm adsorption filter. No significant change in total solids, total fat, and solids-not-fat percentages of skim and whole milk permeates was observed after filtration. Adsorption of Pseudomonas fluorescens at target concentrations of 103 , 102 , and 101 cells/ml was determined in 100ml of dairy standard methods buffer, nutrient broth, whole milk, and skim milk. The average percentage bacterial retentions were 95 ± 5.5%, 95 ± 2.6%, 28 ± 22.1%, and 62 ± 15.5%, respectively.
A treatment was developed for milk to increase the bacterial retention of ~ fluorescens after filtration. The preferred treatment for 100ml of skim milk involved the following final concentrations (v/v): 0.80% disodium ethylenediamine-tetraacetic acid, 0.02% sodium dodecyl sulfate, pH to 7.5 with 1N sodium hydroxide. The average bacterial retention of ~ fluorescens using the treatment was 91 ± 7.1%. Enumeration of bacteria adsorbed to the filter was then conducted using impedance microbiology. When milk was inoculated with ~ fluorescens at target concentrations of 103 , 102 , and 101 cells/ml, an average log bacterial increase of 1.4 ± 0.1 (25x) was obtained. This method will allow for rapid detection of microorganisms in milk by increasing microbial load in the tested sample and eliminating the need for pre-enrichment. / Ph. D.
Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/38443 |
Date | 06 June 2008 |
Creators | Byrne, Robert Duane |
Contributors | Food Science and Technology, Bishop, J. Russell, Duncan, Susan E., Eigel, William N. III, Hackney, Cameron Raj, Jones, Gerald M. |
Publisher | Virginia Tech |
Source Sets | Virginia Tech Theses and Dissertation |
Language | English |
Detected Language | English |
Type | Dissertation, Text |
Format | x, 80 leaves, BTD, application/pdf, application/pdf |
Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
Relation | OCLC# 30924539, LD5655.V856_1994.B976.pdf |
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