Document Detail

Changes in the microflora of haddock fillets and shucked soft-shelled clams after irradiation with Co-60 gamma rays and storage at 0 C and 6 C.
MedLine Citation:
PMID:  13933509     Owner:  NLM     Status:  MEDLINE    
Frequency distribution patterns of aerobic-facultative microflora, obtained by random selection of macrocolonies from samples of haddock fillets and shucked soft-shelled clams before and after treatment with doses of from 50,000 to 800,000 rad of Co(60) gamma rays, are presented, with analyses and interpretation. The data showed that a decided change occurred in the constitution of the microbial populations of both products: from a mixed gram-negative-gram-positive flora to a predominantly gram-positive flora immediately after irradiation. The great majority of these surviving microorganisms were micrococci, sporeforming bacilli, and certain yeasts, molds, and actinomyces. During storage at refrigeration temperatures above freezing, the microflora changed from the descendants of the more radioresistant gram-positive species to the more prolific gram-negative psychrophilic species that flourish at these low temperatures. Micrococci and gram-positive rods declined somewhat during the rise of the actively proteolytic-lipolytic pseudomonads and related species, but still remained at high enough levels to contribute significantly to the spoilage observed at different times in storage. The eventual spoilage of haddock fillets was characterized by discoloration of the cream-white tissue with water-soluble yellow, green, and red bacterial pigments; degradation of the tissue, by proteolytic and other microbial enzymes, to a watery, flaccid mass; and formation of volatile compounds that smelled putrid, rancid, and generally foul and pungent. Shucked soft-shelled clams displayed a different spoilage pattern, changing to a variegated brown-gray and forming a matted or loose gelatinous mass from which arose stale, acrid, putrid, sulfurous odors. These differences are believed to be attributable to the varied biochemical nature of the tissues involved, the Eh potential within the tissues, the time sequence of microfloral change, and the species and types of microorganisms associated with each product. Staphylococci were present in small numbers in some of the samples tested, but did not appear to be species of public health significance. Gram-negative enteric rods were also encountered, but were considered to be of doubtful public health importance. More detailed investigations, designed to study the effects of Co(60) gamma radiations on such microbes in sea foods, would be useful in assessing the problem further.
Related Documents :
18847209 - Influence of irrigation and organic/inorganic fertilization on chemical quality of almo...
10532379 - Intestinal microflora and the interaction with immunocompetent cells.
15934819 - Molecular applications for identifying microbial pathogens in the post-9/11 era.
7835469 - Antimicrobial action of some gras compounds against vibrio vulnificus.
18022269 - Application of bacteriocins in vegetable food biopreservation.
10488839 - Preservative agents in foods. mode of action and microbial resistance mechanisms.
11329019 - Overexpression of petunia chalcone isomerase in tomato results in fruit containing incr...
1698509 - Peptide-amine interactions in the hypothalamic paraventricular nucleus: analysis of gal...
17125539 - Food allergy: nuts and tree nuts.
Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Applied microbiology     Volume:  11     ISSN:  0003-6919     ISO Abbreviation:  Appl Microbiol     Publication Date:  1963 May 
Date Detail:
Created Date:  1963-12-01     Completed Date:  1998-11-01     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  7605802     Medline TA:  Appl Microbiol     Country:  Not Available    
Other Details:
Languages:  eng     Pagination:  229-34     Citation Subset:  OM    
Export Citation:
APA/MLA Format     Download EndNote     Download BibTex
MeSH Terms
Food Contamination*
Food Irradiation*

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

Previous Document:  Effects of substerilization doses of Co-60 gamma radiation on the cold-storage life extension of shu...
Next Document:  Attainment of optimum health.