Document Detail

Occurrence and role of lactic acid bacteria in seafood products.
MedLine Citation:
PMID:  20630312     Owner:  NLM     Status:  MEDLINE    
Lactic acid bacteria (LAB) in fish flesh has long been disregarded because the high post-mortem pH, the low percentage of sugars, the high content of low molecular weight nitrogenous molecules and the low temperature of temperate waters favor the rapid growth of pH-sensitive psychrotolerant marine Gram-negative bacteria like Pseudomonas, Shewanella and Photobacterium. In seafood packed in both vacuum (VP) and modified atmosphere (MAP) packaging commonly CO(2) enriched, the growth of the Gram-negative aerobic bacteria group (predominantly pseudomonads) is effectively inhibited and the number reached by LAB during storage is higher than that achieved in air but always several log units lower than the trimethylamine oxide (TMA-O) reducing and CO(2)-resistant organisms (Shewanella putrefaciens and Photobacterium phosphoreum). Accordingly, LAB are not of much concern in seafood neither aerobically stored nor VP and MAP. However, they may acquire great relevance in lightly preserved fish products (LPFP), including those VP or MAP. Fresh fish presents a very high water activity (aw) value (0.99). However, aw is reduced to about 0.96 when salt (typically 6% WP) is added to the product. As a result, aerobic Gram-negative bacteria are inhibited, which allows the growth of other organisms more resistant to reduced aw, i.e. LAB, and then they may acquire a central role in the microbial events occurring in the product. Changes in consumers' habits have led to an increase of convenient LPFP with a relative long shelf-life (at least 3 weeks) which, on the other hand, may constitute a serious problem from a safety perspective since Listeria monocytogenes and sometimes Clostridium botulinum (mainly type E) may able to grow. In any case the LAB function in marine products is complex, depending on species, strains, interaction with other bacteria and the food matrix. They may have no particular effect or they may be responsible for spoilage and, in certain cases, they may even exert a bioprotective effect in relation to undesirable bacteria. The bioprotective potential of endogenous LAB in relation to pathogens and spoiling bacteria has often been highlighted. However, the technology is still in its infancy compared with foods dairy and meat products in which either the carbohydrate content (dairy products) or sugar and salt added (meat products) favor the acidification by LAB that enable a natural preservation of the product. Successful studies on LAB as probiotic for fish intensify, but this potential is still to be explored for human. Although not usual, some applications of LAB for fermentation of marine products and by-products are described.
Leroi Françoise
Publication Detail:
Type:  Journal Article     Date:  2010-05-25
Journal Detail:
Title:  Food microbiology     Volume:  27     ISSN:  1095-9998     ISO Abbreviation:  Food Microbiol.     Publication Date:  2010 Sep 
Date Detail:
Created Date:  2010-07-15     Completed Date:  2010-10-12     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8601127     Medline TA:  Food Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  698-709     Citation Subset:  IM    
Copyright Information:
Copyright 2010 Elsevier Ltd. All rights reserved.
Laboratoire de Science et Technologie de la Biomasse Marine, Ifremer, Rue de l'Ile d'Yeu, BP 21105, 44311 Nantes Cedex 03, France.
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MeSH Terms
Bacteria / growth & development*
Consumer Product Safety
Fish Products / microbiology*,  standards*
Food Microbiology
Food Packaging
Food Preservation
Lactobacillaceae / physiology*
Seafood / microbiology*
Time Factors

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

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