Document Detail

The correlation method for rapid monitoring of Escherichia coli in foods.
MedLine Citation:
PMID:  11940157     Owner:  NLM     Status:  MEDLINE    
AIMS: A new rapid method was developed to rapidly monitor Escherichia coli counts in foods. MATERIALS AND RESULTS: One ml of modified selective broth with 4-methylumbelliferyl beta-D-glucuronide and 1 ml of food sample were mixed in a sterile test tube and incubated at 37 degrees C. The positive reaction (fluorescence under u.v. light) was monitored at regular 30 min intervals. The positive reaction times in test tubes were compared with actual E. coli numbers from tested samples. The growth of E. coli in test tubes (broth) was much faster than growth on agar. The first experiment was performed to evaluate the rapid correlation method using pure E. coli cultures. The correlation between E. coli counts by the conventional plating method and positive reaction (fluorescence production) times in test tubes was highly agreeable (r(2) = 0 x 95). In the case of low E. coli numbers, such as 2 x 0 log10 cfu ml(-1), the rapid correlation method detected their presence after 10 h incubation. When highly contaminated samples were assayed (8 log10 cfu ml(-1)), the rapid correlation method detected the presence of E. coli after 4 h incubation. In the ground beef experiment, the correlation between fluorescence production time and actual E. coli numbers was also strongly agreeable (r(2) = 0 x 92). CONCLUSIONS: From these results, it is obvious that the new rapid method can rapidly monitor E. coli counts in foods. SIGNIFICANCE AND IMPACT OF THE STUDY: The results indicated that the new method saved about 10-14 h incubation time compared to conventional plating methods. The rapid correlation method required much shorter incubation times compared to conventional plating methods for monitoring E. coli.
P M Gray; M S Rhee; D H Kang
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Publication Detail:
Type:  Comparative Study; Journal Article    
Journal Detail:
Title:  Letters in applied microbiology     Volume:  34     ISSN:  0266-8254     ISO Abbreviation:  Lett. Appl. Microbiol.     Publication Date:  2002  
Date Detail:
Created Date:  2002-04-09     Completed Date:  2002-08-06     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  8510094     Medline TA:  Lett Appl Microbiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  269-73     Citation Subset:  IM    
Department of Food Science and Human Nutrition, Washington State University, Pullman 99164-6376, USA.
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MeSH Terms
Bacteriological Techniques / methods,  standards
Colony Count, Microbial / methods*,  standards
Escherichia coli / isolation & purification*
Fluorescent Dyes / chemistry
Food Microbiology*
Meat Products / microbiology
Reproducibility of Results
Sensitivity and Specificity
Time Factors
Reg. No./Substance:
0/Fluorescent Dyes
Erratum In:
Lett Appl Microbiol. 2003 Apr;19(2):153

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

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