Document Detail


Growth, inactivation and histamine formation of Morganella psychrotolerans and Morganella morganii - development and evaluation of predictive models.
MedLine Citation:
PMID:  18845350     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Mathematical models for growth, heat inactivation and histamine formation by Morganella psychrotolerans and Morganella morganii were studied to evaluate the importance of these bacteria in seafood. Curves for growth and histamine formation by M. psychrotolerans in broth and seafood were generated at constant and changing storage temperatures (n=12). Observed and predicted times to formation of 100, 500 and 2000 ppm histamine were used for evaluation of an existing M. psychrotolerans histamine formation model [Emborg, J., Dalgaard, P., 2008-this issue-this issue. Modelling and predicting the growth and histamine formation by Morganella psychrotolerans. International Journal of Food Microbiology. doi:10.1016/j.ijfoodmicro.2008.08.016] Growth rates for M. psychrotolerans and M. morganii were determined at different constant temperatures from 0 degrees C to 42.5 degrees C whereas heat inactivation was studied between 37.5 degrees C and 60 degrees C. A M. morganii growth and histamine formation model was developed by combining these new data (growth rate model) and data from the existing literature (maximum population density and yield factor for histamine formation). The developed M. morganii model was evaluated by comparison of predicted growth and histamine formation with data from the existing literature. Observed and predicted growth rates for M. psychrotolerans, at constant temperatures, were similar with bias- and accuracy factor values of 1.15 and 1.45, respectively (n=11). On average times to formation of critical concentrations of histamine by M. psychrotolerans were acceptably predicted but the model was not highly accurate. Nevertheless, predictions seemed useful to support decisions concerning safe shelf-life in relation to formulation, storage and distribution of chilled seafood. Parameters for the effect of temperature on growth and inactivation of M. psychrotolerans and M. morganii differed markedly with Tmin of -8.3 to -5.9 degrees C vs. 0.3 to 2.8 degrees C, Topt of 26.0 to 27.0 degrees C vs. 35.9 to 37.2 degrees C and Tmax 32.0 to 33.3 degrees C vs. 44.0 to 47.4 degrees C, D(50 degrees C) of 5.3 min vs. 13.1 min and z-values of 6.8 degrees C and 7.2 degrees C. At temperatures above approximately 15 degrees C M. morganii grew faster than M. psychrotolerans. Bias- and accuracy factor-values of 1.41 and 2.44 (n=93) showed the predicted growth of M. morganii to be faster than previously observed in fresh fish and broth. In agreement with this, predicted times to formation of critical histamine concentrations by M. morganii were on average shorter than observed in fresh fish. A combined model was suggested to predict histamine formation by both psychrotolerant and mesophilic Morganella during storage of fresh fish between 0 degrees C and 37 degrees C.
Authors:
Jette Emborg; Paw Dalgaard
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-09-04
Journal Detail:
Title:  International journal of food microbiology     Volume:  128     ISSN:  0168-1605     ISO Abbreviation:  Int. J. Food Microbiol.     Publication Date:  2008 Dec 
Date Detail:
Created Date:  2008-11-14     Completed Date:  2009-01-29     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8412849     Medline TA:  Int J Food Microbiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  234-43     Citation Subset:  IM    
Affiliation:
Department of Seafood Research, National Institute of Aquatic Resources, Technical University of Denmark, Søltofts Plads, Building 221, DK-2800, Kgs. Lyngby, Denmark. jem@aqua.dtu.dk
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MeSH Terms
Descriptor/Qualifier:
Animals
Colony Count, Microbial
Consumer Product Safety
Food Microbiology
Histamine / biosynthesis*
Humans
Models, Biological*
Morganella / growth & development*,  metabolism*
Morganella morganii / growth & development*,  metabolism*
Predictive Value of Tests
Seafood* / microbiology,  standards
Species Specificity
Temperature
Chemical
Reg. No./Substance:
51-45-6/Histamine

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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