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Acid habituation of Escherichia coli and the potential role of cyclopropane fatty acids in low pH tolerance


Brown, JL and Ross, T and Nichols, PD and McMeekin, TA, Acid habituation of Escherichia coli and the potential role of cyclopropane fatty acids in low pH tolerance, International Journal of Food Microbiology, 37, (2-3) pp. 163-173. ISSN 0168-1605 (1997) [Refereed Article]

DOI: doi:10.1016/S0168-1605(97)00068-8


A reversible adaptive tolerance to low pH termed 'acid habituation' is demonstrated for five strains of Escherichia coli. Superimposed upon the intrinsic acid tolerance of individual strains, acid habituation significantly enhances the survival of exponential phase cultures exposed to a lethal acid challenge (pH 3.0), and minimises inter-strain variability in acid tolerance. The fatty acid composition of acid habituated, non-habituated, and de-habituated exponential phase cultures is also reported. During acid habituation, monounsaturated fatty acids (16:1ω7c and 18:1ω7c) present in the phospholipids of E. coli are either converted to their cyclopropane derivatives (cy17:0 and cy19:0), or replaced by saturated fatty acids. The acid tolerance of individual strains of E. coli appears to be correlated with membrane cyclopropane fatty acid content and, thus, it is postulated that increased levels of cyclopropane fatty acids may enhance the survival of microbial cells exposed to low pH. The results presented illustrate the remarkable capacity of E. coli to adapt to environmental challenges, and have significant implications for the survival of spoilage and pathogenic bacteria, and hence for food safety.

Item Details

Item Type:Refereed Article
Research Division:Engineering
Research Group:Manufacturing engineering
Research Field:Manufacturing safety and quality
Objective Division:Manufacturing
Objective Group:Processed food products and beverages (excl. dairy products)
Objective Field:Processed meat products
UTAS Author:Brown, JL (Dr Janelle Brown)
UTAS Author:Ross, T (Professor Tom Ross)
UTAS Author:McMeekin, TA (Professor Thomas McMeekin)
ID Code:10746
Year Published:1997
Web of Science® Times Cited:190
Deposited By:Agricultural Science
Deposited On:1997-08-01
Last Modified:2011-08-11

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