Enumeration of Total Coliforms, Fecal Coliforms, and Escherichia coli in Foods by Hydrophobic Grid Membrane Filter: Collaborative Study

1984 ◽  
Vol 67 (4) ◽  
pp. 812-823
Author(s):  
Phyllis Entis ◽  
◽  
B Bennett ◽  
M H Brodsky ◽  
D M Burgener ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Collaborative Study ◽  
Reference Method ◽  
Black Pepper ◽  
Fecal Coliforms ◽  
Filter Method ◽  
Total Coliforms ◽  
E Coli ◽  
Membrane Filter Method

Abstract A collaborative study was conducted in 18 laboratories to assess the performance of the hydrophobic grid membrane filter method against that of the AOAC official first action method 46.013-46.016 for enumerating total and fecal coliforms and Escherichia coli. The study was carried out on frozen breaded fish, raw comminuted poultry, unroasted walnut pieces, ground black pepper, and cheddar cheese. The hydrophobic grid membrane filter method recovered significantly larger numbers of target bacteria in 7 of the food/analysis combinations: fecal coliforms in fish; E. coli in poultry; fecal coliforms and E. coli in walnuts; and total coliforms, fecal coliforms and E. coli in black pepper. Random error (Sr2) associated with the hydrophobic grid membrane filter method was significantly lower than that of the reference method in over 30% of the paired sample series. The hydrophobic grid membrane filter method for total coliform, fecal coliform, and E. coli enumeration in foods has been adopted official first action.

Enumeration of Total Coliforms, Fecal Coliforms, and Escherichia coli in Foods by Hydrophobic Grid Membrane Filter: Supplementary Report

1984 ◽  
Vol 67 (4) ◽  
pp. 811-812
Author(s):  
Phyllis Entis
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Total Coliform ◽  
Fecal Coliforms ◽  
Poultry Meat ◽  
Filter Method ◽  
Total Coliforms ◽  
The Media ◽  
Aoac Method ◽  
Membrane Filter Method

Abstract Raw, comminuted poultry meat was used to determine the specificity of the media and incubation conditions used in the hydrophobic grid membrane filter method. Confirmation rates for target colonies were 100% for total coliforms, 98% for fecal coliforms, and 97-99% for Escherichia coli. The results of total coliform enumeration in 30 pasteurized milk samples by both the hydrophobic grid membrane filter method and AOAC method 46.013-46.016 are also reported.

Rapid Hydrophobic Grid Membrane Filter Method for Salmonella Detection in Selected Foods: Collaborative Study

1985 ◽  
Vol 68 (3) ◽  
pp. 555-564
Author(s):  
Phyllis Entis
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reference Method ◽  
Black Pepper ◽  
Poultry Meat ◽  
Filter Method ◽  
Dry Milk ◽  
Membrane Filter Method ◽  
Nonfat Dry Milk ◽  
Egg Powder

Abstract A collaborative study was carried out in 36 laboratories to validate a hydrophobic grid membrane filter method for rapid (2-3 days) Salmonella detection by comparing its performance against the AOAC/ BAM reference method. Six products were included in the study: semisweet chocolate, raw ground poultry meat, ground black pepper, cheese powder, egg powder, and nonfat dry milk. With the exception of the naturally contaminated poultry, all products were inoculated in advance with low concentrations of a variety of Salmonella serotypes. The hydrophobic grid membrane filter method detected the following numbers of positive samples (results of the AOAC/BAM reference method are shown in parentheses): chocolate, 67(68); raw ground poultry, 133(131); ground black pepper, 57(56); cheese powder, 81(80); egg powder, 51(45); and nonfat dry milk, 68(72). The 2 methods did not differ significantly at the 95% confidence level in any of the 6 foods. The hydrophobic grid membrane filter method has been adopted official first action for detection of Salmonella in selected foods.

scholarly journals Direct 24-Hour Presumptive Enumeration of Escherichia coli 0157:H7 in Foods Using Hydrophobic Grid Membrane Filter Followed by Serological Confirmation: Collaborative Study

1998 ◽  
Vol 81 (2) ◽  
pp. 403-418 ◽  
Author(s):  
Phyllis Entis ◽  
◽  
D Bryant ◽  
J Bryant ◽  
R G Bryant ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Collaborative Study ◽  
Reference Method ◽  
Test Method ◽  
Cottage Cheese ◽  
Apple Cider ◽  
Dairy Foods ◽  
E Coli ◽  
Repeatability And Reproducibility

abstract Fifteen laboratories took part in a collaborative study to validate a method for enumerating Escherichia coli 0157:H7. The method is based on use of a hydrophobic grid membrane filter and consists of 24 h presumptive enumeration on SD-39 Agar and serological confirmation to yield a confirmed E. coli 0157:H7 count. Six food products were analyzed: pasteurized apple cider, pasteurized 2% milk, cottage cheese, cooked ground pork, raw ground beef, and frozen whole egg. The test method produced significantly higher confirmed count results than did the reference method for milk, pork, and beef. Test method results were numerically higher than but statistically equivalent to reference method results for cheese, cider, and egg. The test method produced lower repeatability and reproducibility values than did the reference method for most food/inoculation level combinations and values very similar to those of the reference method for the remaining combinations. Overall, 94% of presumptive positive isolates from the test method were confirmed serologically as E. coli 0157:H7, and 98% of these were also biochemically typical of E. coli 0157:H7 (completed test). Corresponding rates for the reference method were 69 and 98%, respectively. On the basis of the results of this collaborative study and the precollaborative study that preceded it, it is recommended that this method be adopted official first action for enumeration of E. coli 0157:H7 in meats, poultry, dairy foods, infant formula, liquid eggs, mayonnaise, and apple cider

Enumeration of β-Glucuronidase-Positive Escherichia coli in Foods by Using the ISO-GRID Method with SD-39 Agar

1998 ◽  
Vol 61 (7) ◽  
pp. 913-916 ◽  
Author(s):  
PHYLLIS ENTIS ◽  
IRINA LERNER
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Reference Method ◽  
Grid Method ◽  
Test Method ◽  
Cottage Cheese ◽  
Filter Method ◽  
Official Method ◽  
Membrane Filter Method ◽  
Aoac Official

A study was undertaken to compare β-glucuronidase-positive Escherichia coli counts produced by the ISO-GRID hydrophobic grid membrane filter method using SD-39 agar (test method) with those produced by AOAC Official Method 990.11, an existing ISO-GRID method using lactose monensin glucuronate agar and buffered MUG agar (reference method). The methods were evaluated using 21 food products, with three independent lots of five replicate samples analyzed per product by both methods. The test and reference methods were statistically equivalent for 19 of the 21 products; frozen, raw ground lamb produced significantly higher counts using the reference method, whereas counts obtained from cottage cheese were significantly higher using the SD-39 agar-based method.

scholarly journals Sampling considerations for herd-level measurement of faecal Escherichia coli antimicrobial resistance in finisher pigs

1999 ◽  
Vol 122 (3) ◽  
pp. 485-496 ◽  
Author(s):  
R. H. DUNLOP ◽  
S. A. McEWEN ◽  
A. H. MEEK ◽  
R. M. FRIENDSHIP ◽  
W. D. BLACK ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Resistance ◽  
Membrane Filter ◽  
Filter Method ◽  
Animal Testing ◽  
E Coli ◽  
Level Measurement ◽  
Faecal Samples ◽  
Membrane Filter Method ◽  
Estimate Prevalence

The objective of this study was to determine the most efficient means of sampling faeces of finisher pigs for accurate and precise farm-level estimates of antimicrobial resistance among faecal Escherichia coli. Resistance to tetracycline and gentamicin of 8250 isolates of E. coli from 55 finisher pigs on one farm was measured with a hydrophobic grid membrane filter method. The between-pig, within-pen component of variance in resistance was large (97·5%), while between-pen, within-room and between-room components were small (2·5% and 0%, respectively). Using these resistance data, the abilities of two sampling strategies to estimate prevalence were modelled with a Monte Carlo ‘bootstrap’ procedure. Compositing faecal samples from several pigs before testing produced unbiased and precise estimates of prevalence and is simpler technically than individual animal testing.

Enumeration of Coliforms in Nonfat Dry Milk and Canned Custard by Hydrophobic Grid Membrane Filter Method: Collaborative Study

1983 ◽  
Vol 66 (4) ◽  
pp. 897-904
Author(s):  
Phyllis Entis ◽  
◽  
B W Ciebin ◽  
V Gipson ◽  
M Grahn ◽  
...  
Keyword(s):  
Membrane Filter ◽  
Collaborative Study ◽  
Reference Method ◽  
New Method ◽  
Filter Method ◽  
Official Method ◽  
Random Errors ◽  
Dry Milk ◽  
Membrane Filter Method ◽  
Nonfat Dry Milk

Abstract A collaborative study was conducted in 14 laboratories to evaluate the performance of the hydrophobic grid membrane filter method against the official final action method, 46.016, for enumeration of colif orms in foods. Twelve artificially contaminated samples of nonfat dry milk and canned custard were analyzed by each laboratory. The random errors (Sr2) associated with the hydrophobic grid membrane filter method were significantly lower than those of the official method, and the counts obtained by the new method fell within the 95% confidence interval of the reference method. The colif orm counts obtained by tiie hydrophobic grid membrane filter method did not differ significantly from those obtained by the reference method as measured by a 3-way analysis of variance. The new method has been adopted official first action.

scholarly journals Two-Day Hydrophobic Grid Membrane Filter Method for Yeast and Mold Enumeration in Foods Using YM-11 Agar: Collaborative Study

1996 ◽  
Vol 79 (5) ◽  
pp. 1069-1082 ◽  
Author(s):  
Phyllis Entis ◽  
A Athar ◽  
M Ballenger ◽  
M S Bendeck ◽  
W Birbari ◽  
...  
Keyword(s):  
Orange Juice ◽  
Membrane Filter ◽  
Collaborative Study ◽  
Ground Beef ◽  
Reference Method ◽  
Test Method ◽  
Filter Method ◽  
Garlic Powder ◽  
Reference Methods ◽  
Membrane Filter Method

Abstract Twenty laboratories participated in a collaborative study to validate a 2-day hydrophobic grid membrane filter method using YM-11 agar for enumeration of yeast and mold in foods. Six naturally contaminated food products were included in the study: garlic powder, raw ground beef, walnuts, flour/meal, orange juice, and yogurt. The test method produced significantly higher results than the 5-day pour plate reference method for orange juice and significantly lower, though numerically similar, results for walnuts and yogurt. Differences between the test and reference methods were not significant for garlic powder, raw ground beef, or flour/meal. Repeatability and reproducibility were similar for both the test and reference methods in all cases. The hydrophobic grid membrane filter method for enumeration of yeast and mold in foods has been adopted by AOAC INTERNATIONAL.

Membrane Filter Method Based on FC-5-Bromo-4-Chloro-3-lndolyl-β-d-Glucuronide Medium Facilitates Enumeration of Escherichia coli in Foods and Poultry Carcass Rinses

1998 ◽  
Vol 61 (3) ◽  
pp. 360-364 ◽  
Author(s):  
A. N. SHARPE ◽  
L. J. PARRINGTON
Keyword(s):  
Escherichia Coli ◽  
Membrane Filter ◽  
Most Probable Number ◽  
Filter Method ◽  
Simple Method ◽  
Probable Number ◽  
E Coli ◽  
Membrane Filter Method ◽  
Alfalfa Sprouts ◽  
Bean Sprouts

Three enumeration methods for Escherichia coli in foods, the Health Protection Branch most-probable-number (MPN) method MFHPB-19, a hydrophobic grid membrane filter method MFHPB-26 (HGMF-indole), and a hydrophobic grid membrane filter method utilizing 5-bromo-4-chloro-3-indolyl-β-d-glucuronide in a (modified) mFC agar (HGMF-FC-BCIG) were compared in 80 food samples that included naturally and artificially contaminated raw vegetables, mung bean and alfalfa sprouts, raw meats, and chicken carcass rinses. The number of samples confirmed as positive for E. coli were 44, 36, and 42 for the MPN, HGMF-indole, and HGMF-FC-BCIG methods, respectively. By the MPN method, E. coli was detected in 3 samples at levels below the limits of detection of the HGMFs; but the MPN method was very time-consuming. With the HGMF-indole procedure E. coli was missed in 4 artificially contaminated samples. With the HGMF-FC-BCIG method E. coli was enumerated in 1 sample of bean sprouts missed by both the MPN and HGMF-indole procedures. High levels of indole-positive Klebsiella spp. in bean sprouts interfered with the HGMF-indole method, but the blue colonies of E. coli were easily observed in the HGMF-FC-BCIG method. Specificity of the HGMF-FC-BCIG method is high enough that routine confirmation should be unnecessary; however, confirmation of presumptive E. coli is easier since no lethal indole-staining step is involved. It appears to be a very simple method for quantifying E. coli in foods or carcass rinses.

Detection of Escherichia coli by the nutrient agar plus 4-methylumbelliferyl β-D-glucuronide (MUG) membrane filter method

1993 ◽  
Vol 39 (11) ◽  
pp. 1066-1070 ◽  
Author(s):  
Lois C. Shadix ◽  
Michele E. Dunnigan ◽  
Eugene W. Rice
Keyword(s):  
Escherichia Coli ◽  
Membrane Filtration ◽  
Membrane Filter ◽  
Nutrient Agar ◽  
Coliform Bacteria ◽  
Filter Method ◽  
Isolation Medium ◽  
Long Wavelength ◽  
E Coli ◽  
Membrane Filter Method

A two-step membrane filter procedure was evaluated to determine the ability to differentiate Escherichia coli from other coliform bacteria recovered from water. M-Endo LES agar incubated at 35 °C for 24 ± 2 h was used as the initial isolation medium. Membranes containing coliform colonies were transferred to nutrient agar plus 4-methylumbelliferyl β-D-glucuronide (MUG) and incubated for an additional 4 h at 35 °C. Escherichia coli colonies were distinguished by fluorescence when viewed under a long-wavelength ultraviolet light. A total of 119 MUG-positive colonies were isolated from 15 water sources, of which 115 (96.6%) were identified as E. coli. An examination of 182 pure culture environmental E. coli isolates revealed that 167 isolates (91.8%) exhibited fluorescence on the nutrient agar plus MUG medium. Survivors of E. coli cultures exposed to chlorination were also capable of producing a positive MUG reaction.Key words: membrane filtration, 4-methylumbelliferyl β-D-glucuronide (MUG), Escherichia coli, water.

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