Comparison of a Rapid Plate Count and MPN Methods for Enumeration of Fecal Coliforms and Escherichia coli in Soft-Shell Clams

1995 ◽  
Vol 58 (11) ◽  
pp. 1197-1200 ◽  
Author(s):  
GUADALUPE R. GARCIA ◽  
ROBERT E. HAYMOND ◽  
DIANE M. SPRAGUE ◽  
EMMA R. SINGLETON ◽  
JAMES T. PEELER ◽  
...  

A direct elevated temperature plate count method utilizing modified fecal coliform agar with rosolic acid (ETPC/mFC) was compared to 5-tube and 3-tube most probable number (MPN) procedures for its accuracy in enumerating fecal coliforms and Escherichia coli in naturally and artificially contaminated soft-shell clams (Mya arenaria). The results indicated that the extent of overall recovery of fecal coliforms was similar in the two methods tested. Therefore, the ETPC/mFC method may be considered as a rapid procedure for fecal coliform screening during depuration of soft-shell clams.

1977 ◽  
Vol 40 (11) ◽  
pp. 763-764 ◽  
Author(s):  
S. VARGA ◽  
R. E. DOBSON ◽  
R. EARLE

The Elevated Temperature Plate Count procedure of Hefferman and Cabelli was assessed to measure the sanitary quality of soft shell clams. The method, compared to the standard MPN procedure, underestimated the densities of fecal coliforms by about 10%. The estimated cell densities of Escherichia coli and Enterobacter aerogenes in saline suspension were about 20% lower than the estimate obtained on nutrient agar plates. Thus, the fecal coliform standard used in the assessment of sanitary quality of clams would need to be modified when the analysis is conducted by the Elevated Temperature Plate Count procedure.


2007 ◽  
Vol 53 (6) ◽  
pp. 798-801 ◽  
Author(s):  
Tamara Garcia-Armisen ◽  
Josué Prats ◽  
Pierre Servais

Fecal coliforms (FC) counts were compared with Escherichia coli counts in differently contaminated freshwater samples (n = 166). FC were enumerated by plate count on triphenyl 2,3,5-tetrazolium chloride Tergitol medium. Escherichia coli were enumerated by the most probable number microplate method based on the detection of glucuronidase activity. FC and E. coli counts were highly correlated; an average E. coli/FC ratio equal to 0.77 was found, meaning that on average, 77% of FC were E. coli. Knowing the E. coli/FC ratio allows us to convert the historical microbiological quality data expressed in FC counts into E. coli abundance and thus to compare with present and future monitoring data that are (or will be) based on E. coli enumeration.


1984 ◽  
Vol 47 (7) ◽  
pp. 557-561 ◽  
Author(s):  
MILES L. MOTES ◽  
ROLAND M. McPHEARSON ◽  
ANGELO DePAOLA

Three international methods were evaluated for enumerating Escherichia coli in estuarine waters, oysters (Crassostrea virginica), mussels (Mytilus edilus) and clams (Mercenaria mercenaria). Results of the French most probable number (MPN) method, a modification of the MacKenzie, Taylor and Gilbert (1948) method, were obtained within 48 h and compared favorably with those obtained by the standard American Public Health Association (APHA) MPN procedure in all sample types. Results of the Australian Anderson and Baird-Parker plate count method, obtained within 24 h, were significantly lower than those obtained with the standard APHA procedure for all sample types. Results of the British roll tube method, a 24-h direct count method, compared favorably with the standard APHA procedure only for mussels and waters.


1976 ◽  
Vol 39 (5) ◽  
pp. 322-324 ◽  
Author(s):  
W. H. ANDREWS ◽  
C. D. DIGGS ◽  
J. J. MIESCIER ◽  
C. R. WILSON ◽  
W. N. ADAMS ◽  
...  

To determine the relationship of most probable number (MPN) of the total and fecal coliform groups in shellfish and shellfish-growing waters to the presence of Salmonella in quahaugs (Mercenaria mercenaria), a microbiological survey of 214 samples of the quahaug, or hard-shell clam, was done over 24 months. For purposes of this study, waters were classified as safe for shellfish harvesting by one of two criteria: (a) a total coliform MPN of ≤ 70/100 ml of water or (b) a fecal coliform MPN value of ⩽ 14/100 ml of water. None of the quahaug samples harvested from waters meeting these standards contained Salmonella. Additionally, Salmonella was not detected in any of the quahaug samples meeting the wholesale market quality standard of 230 fecal coliforms per 100 g of shellfish as specified by the National Shellfish Sanitation Program. An increase in the total coliform and fecal coliform MPN of the waters more closely paralleled an increase in the fecal coliform MPN, as compared to the total coliform MPN of the quahaug meats. Five Salmonella serotypes, including Salmonella parathyphi B, were found singly and in combination in five (2.3%) of the quahaug samples in this survey.


1990 ◽  
Vol 53 (12) ◽  
pp. 1052-1057 ◽  
Author(s):  
TUU-JYI CHAI ◽  
TZYY-JAN HAN ◽  
RALPH R. COCKEY ◽  
PATRICIA C. HENRY

A total of 472 samples of soft-shell clams (Mya arenaria), collected from three major clam harvest areas in the Chesapeake Bay and dockside check stations, was analyzed for standard plate count (SPC), total coliforms, fecal coliforms, Escherichia coli, and coliphages. SPC increased during the summer season. SPC geometric means of 2.6 × 104, 6.9 × 104, and 7.2 × 104/g, respectively, were found in three major harvest areas. Fecal coliforms remained relatively stable with geometric means of 30, 54, and 62/100 g. As seasonal temperatures increased, the total coliform geometric means declined slightly ranging from 1,500 to 6,300/100 g. E. coli means were low (< 27/100 g). The occurrence and levels of male-specific coliphages were also low and did not correlate with bacteriological quality. No significant microbiological quality difference was found between soft-shell clams sampled from harvest waters and check stations. Results indicate that the microbiological quality of soft-shell clams either at harvest or check stations was satisfactory.


1995 ◽  
Vol 58 (6) ◽  
pp. 648-650
Author(s):  
JAMES T. PEELER ◽  
THOMAS E. GRAHAM ◽  
LARRY J. MATURIN

Precision parameters from four microbiological analytical methods (coliform most probable number [MPN], fecal coliform MPN, Staphylococcus aureus plate count and standard plate count) were computed for the Shellfish Quality Assurance Program of the U.S. Food and Drug Administration (FDA). The pooled reproducibility variance (SR2) for the four methods from 1973 to 1989 were 0.0778, 0.1181, 0.0137, and 0.0087, respectively.


2006 ◽  
Vol 69 (10) ◽  
pp. 2500-2503 ◽  
Author(s):  
P. PAULSEN ◽  
E. SCHOPF ◽  
F. J. M. SMULDERS

An automated most-probable-number (MPN) system for the enumeration of total bacterial flora and Escherichia coli was compared with plate count agar and tryptone-bile-glucuronide (TBX) and ColiID (in-house method) agar methodology. The MPN partitioning of sample aliquots was done automatically on a disposable card containing 48 wells of 3 different volumes, i.e., 16 replicates per volume. Bacterial growth was detected by the formation of fluorescent 4-methylumbilliferone. After incubation, the number of fluorescent wells was read with a separate device, and the MPN was calculated automatically. A total of 180 naturally contaminated samples were tested (pig and cattle carcass surfaces, n = 63; frozen minced meat, n = 62; and refrigerated minced meat, n = 55). Plate count agar results and MPN were highly correlated (r = 0.99), with log MPN =−0.25 + 1.05·log CFU (plate count agar) (n = 163; range, 2.2 to 7.5 log CFU/g or cm2). Only a few discrepancies were recorded. In two samples (1.1%), the differences were ≥1.0 log; in three samples (1.7%), the differences were ≥0.5 log. For E. coli, regression analysis was done for all three methods for 80 minced meat samples, which were above the limit of detection (1.0 log CFU/g): log MPN = 0.18 + 0.98·log CFU (TBX), r = 0.96, and log MPN =−0.02 + 0.99·log CFU (ColiID), r = 0.99 (range, 1.0 to 4.2 log CFU/g). Four discrepant results were recorded, with differences of >0.5 but <1.0 log unit. These results suggest that the automated MPN method described is a suitable and labor-saving alternative to colony count techniques for total bacterial flora and E. coli determination in minced meat or on carcass surfaces.


1980 ◽  
Vol 43 (2) ◽  
pp. 124-126 ◽  
Author(s):  
FRANK O. PERKINS ◽  
DEXTER S. HAVEN ◽  
REINALDO MORALES-ALAMO ◽  
MARTHA W. RHODES

A general review of knowledge concerning bacterial accumulation and depletion by commercially significant bivalve molluses is presented. Naturally contaminated shellfish can eliminate fecal coliforms (FC) in 48 h to levels below most market standards over a wide range of environmental conditions when sea water flowing to the molluses is treated so that fecal coliform levels are indeterminate or marginally determinate as assayed by standard methodology. Most probable number (MPN) enumerations of shellfish depurated for 48 h by the authors yielded a median value of < 18 FC/100 g of oyster (Crassostrea Virginica) meats with < 10% of the samples exceeding 78 FC/100 g.


1998 ◽  
Vol 61 (3) ◽  
pp. 280-284 ◽  
Author(s):  
MICKEY E. PARISH

A salmonellosis outbreak occurred during the summer of 1995 among individuals who consumed nonpasteurized orange juice from a Florida citrus-processing facility. Clinical isolates were identified by the Centers for Disease Control as Salmonella serovars Hartford, Gaminara, and Rubislaw. At the processing facility, 70 samples (equipment swabs, fruit surface swabs, juice, and miscellaneous environmental samples) were collected before, during, and after processing runs on two different dates. Bottled juice samples from eight previous extraction dates were also collected. Total plate counts, fecal coliforms, and Escherichia coli were enumerated for each sample. Analyses for Salmonella cells were conducted on all juice samples, fruit surface swabs, environmental samples, and selected equipment swabs using direct enrichment and pre-enrichment techniques. Salmonella serovars Hartford, Rubislaw, Saintpaul, and Newport were detected from either juice, unwashed fruit surfaces, or amphibians (Hyla cinerea and Bufo terrestris) captured outside the processing building. Salmonella cells in juice were associated with population levels of fecal coliforms and E. coli above the upper most probable number (MPN) limits of detection (>110/ml).


2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Sohana Al Sanjee ◽  
Md. Ekramul Karim

The present study aims at the microbiological analysis of export oriented frozen fishes, namely, Jew fish, Tongue Sole fish, Cuttle fish, Ribbon fish, Queen fish, and fish processing water and ice from a view of public health safety and international trade. Microbiological analysis includes the determination of total viable aerobic count by standard plate count method and enumeration of total coliforms and fecal coliforms by most probable number method. The presence of specific fish pathogens such asSalmonellaspp. andVibrio choleraewere also investigated. The TVAC of all the samples was estimated below5×105 cfu/g whereas the total coliforms and fecal coliforms count were found below 100 MPN/g and 10 MPN/g, respectively, which meet the acceptable limit specified by International Commission of Microbiological Specification for Food. The microbiological analysis of water and ice also complies with the specifications havingTVAC<20 cfu/mL, and total coliforms and fecal coliforms count were below the limit detection of the MPN method. Specific fish pathogens such asSalmonellasp. andV. choleraewere found absent in all the samples under the investigation. From this study, it can be concluded that the investigated frozen fishes were eligible for export purpose and also safe for human consumption.


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