scholarly journals Evaluation of the 3M™ Petrifilm™ Rapid E. coli/Coliform Count Plate for the Enumeration of E. coli and Coliforms: Collaborative Study, First Action: 2018.13

2020 ◽  
Vol 103 (2) ◽  
pp. 513-522
Author(s):  
Patrick Bird ◽  
Benjamin Bastin ◽  
Nicole Klass ◽  
Erin Crowley ◽  
James Agin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Collaborative Study ◽  
Control Level ◽  
Reference Method ◽  
Colony Count ◽  
Coliform Bacteria ◽  
E Coli ◽  
Coliform Count ◽  
Reference Methods ◽  
Animal Feeding

Abstract Background The 3M™ Petrifilm™ Rapid E. coli/Coliform Count Plate is a selective and differential sample-ready-culture medium designed for the rapid enumeration of Escherichia coli (E. coli) and coliforms in the food and beverage industries. Objective The 3M Petrifilm Rapid E. coli/Coliform Count Plate was compared to the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) Chapter 4 Enumeration of Escherichia coli and the Coliform Bacteria, the International Organization of Standards (ISO) 4832:2006 Microbiology of food and animal feeding stuffs — Horizontal method for the enumeration of coliforms—Colony-count technique, and ISO 16649-2:2017 Microbiology of food and animal feeding stuffs—Horizontal method for the enumeration of beta-glucuronidase-positive Escherichia coli—Part 2 Colony-count technique at 44 degrees C using bromo-4-chloro-3- indolyl beta-D-glucuronide methods for the enumeration of E. coli and coliforms in dry dog kibble. Method The candidate method was evaluated using two diluents, Butterfield's phosphate buffered diluent and peptone salt solution, in a paired study design with each reference method in a multi-laboratory collaborative study following the current AOAC Validation Guidelines. Three target contamination levels and an uninoculated control level were evaluated. Results The candidate and reference methods were not statistically different at each contamination level. Reproducibility values obtained during the collaborative study were similar between the candidate and reference methods. Conclusion These results demonstrate that the candidate method is equivalent to the reference methods. Highlight 3M Petrifilm Rapid E. coli/Coliform Count Plate was recommended for Official First Action status for enumeration of E. coli and coliforms in a broad range of foods and environmental surfaces.

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

scholarly journals Comparison of Colilert-18 with miniaturised most probable number method for monitoring of Escherichia coli in bathing water

2015 ◽  
Vol 14 (1) ◽  
pp. 121-131 ◽  
Author(s):  
Ananda Tiwari ◽  
Seppo I. Niemelä ◽  
Asko Vepsäläinen ◽  
Jarkko Rapala ◽  
Seija Kalso ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
False Negative ◽  
Reference Method ◽  
Water Quality Monitoring ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Probable Number ◽  
E Coli ◽  
Negative Results ◽  
Bathing Water

The purpose of this equivalence study was to compare an alternative method, Colilert-18 Quanti-Tray (ISO 9308-2) with the European bathing water directive (2006/7/EC) reference method, the miniaturised most probable number (MMPN) method (ISO 9308-3), for the analysis of Escherichia coli. Six laboratories analysed a total of 263 bathing water samples in Finland. The comparison was carried out according to ISO 17994:2004. The recovery of E. coli using the Colilert-18 method was 7.0% and 8.6% lower than that of the MMPN method after 48 hours and 72 hours of incubation, respectively. The confirmation rate of presumptive E. coli-positive wells in the Colilert-18 and MMPN methods was high (97.8% and 98.0%, respectively). However, the testing of presumptive E. coli-negative but coliform bacteria-positive (yellow but not fluorescent) Colilert-18 wells revealed 7.3% false negative results. There were more false negatives in the naturally contaminated waters than in the samples spiked with waste water. The difference between the recovery of Colilert-18 and the MMPN method was considered not significant, and subsequently the methods are considered as equivalent for bathing water quality monitoring in Finland. Future bathing water method equivalence verification studies may use the data reported herein. The laboratories should make sure that any wells showing even minor fluorescence will be determined as positive for E. coli.

scholarly journals Independent Validation for the Polyskope 1.0 Multiplex Pathogen Detection Assay for the Detection of Shiga Toxin-Producing Escherichia coli Non-O157 STEC, Escherichia coli O157, Listeria monocytogenes, and Salmonella Species

2019 ◽  
Vol 102 (5) ◽  
pp. 1455-1471
Author(s):  
Benjamin Bastin ◽  
Leo Horine ◽  
Patrick Bird ◽  
M Joseph Benzinger ◽  
James Agin ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Listeria Monocytogenes ◽  
Shiga Toxin ◽  
Reference Method ◽  
Test Method ◽  
Escherichia Coli O157 ◽  
E Coli ◽  
Independent Validation ◽  
Reference Methods ◽  
Environmental Surface

Abstract Background: The Polyskope 1.0 Multiplex Assay is a novel test to simultaneously detect Escherichia coli O157, non-O157 Shiga Toxin-Producing E. coli (STEC), Listeria monocytogenes, and Salmonella species in a single enrichment using real-time PCR. Objective: A Performance Tested MethodSM study was conducted to validate Polyskope 1.0 for inclusivity and exclusivity as well as a matrix comparison study. Method: This assay was evaluated in an unpaired independent validation study compared with reference methods according to AOAC INTERNATIONAL validation guidelines. Polyskope 1.0 evaluated raw ground beef (25 g), deli turkey (25 g), baby spinach (25 g), and stainless-steel environmental surface sponges (4 × 4 in. test area) after inoculation with a suspension of the three target microorganisms. All matrices were compared with appropriate reference methods from the U.S. Food and Drug Administration Bacteriological Analytical Manual, U.S. Department of Agriculture Food Safety and Inspection Service Microbiology Laboratory Guidebook, or International Organization for Standardization standards. Results: Polyskope 1.0 demonstrated no statistically significant differences between candidate and reference method results or between presumptive and confirmed results for three food matrices and one environmental surface. Results from inclusivity and exclusivity evaluations indicated the test method can accurately detect the target analytes and excluded all nontarget organisms. No differences were observed with the stability or lot-to-lot evaluations. Polyskope 1.0 demonstrated robustness by remaining unaffected by small variations in method parameters, which had no statistically significant effect on the results for all eight variations. Conclusions and Highlights: Polyskope 1.0 was shown to be a specific, highly accurate, and robust method for the detection of Listeria monocytogenes, Salmonella species, non-O157 STECs, and E. coli O157 across four matrices.

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.

scholarly journals MC-Media Pad EC for Enumeration of Escherichia coli and Coliforms in a Variety of Foods

2019 ◽  
Vol 102 (5) ◽  
pp. 1502-1515
Author(s):  
Hajime Teramura ◽  
Aya Ogura ◽  
Linda Everis ◽  
Gail Betts
Keyword(s):  
Escherichia Coli ◽  
Incubation Temperature ◽  
Paired Comparison ◽  
Reference Method ◽  
Sample Volume ◽  
Suitable Alternative ◽  
Total Coliforms ◽  
E Coli ◽  
Reference Methods ◽  
Significant Difference

Abstract Background: Standard coliform count methods require preparation of agar, the use of pour-plate technique, the overlay of agar, and in some cases, the transfer of suspect colonies to broth medium for confirmation. The MC-Media Pad EC for enumeration of Escherichia coli and coliforms is a ready-to-use dehydrated sheet medium with no agar preparation, no spreader, and no confirmation step required. Objective: Using a paired study design, the MC-Media Pad EC was compared with standard method ISO 4832:2006. Ten matrixes including raw ground pork, raw chicken, cream, cream cheese, ready-to-cook vegetable mix, vegetable juice, cooked prawns, crab pâté, ham sandwiches, and cooked rice were evaluated in the study. Methods: Each matrix was tested at three levels of contamination (approximately 102, 104, and 106 CFU/g). Five replicate 10 g test portions per level were tested in a paired comparison by the MC-Media Pad EC, ISO 4832:2006, and ISO 16649-2:2001 (Part 2) methods. In addition, inclusivity/exclusivity, robustness, and product consistency and stability were evaluated. Results: The candidate and reference methods demonstrated standard deviations ranging from 0.034 to 0.188 and 0.028 to 0.181, respectively, for E. coli counts and 0.047–0.188 and 0.025–0.157, respectively, for total coliforms. The difference of means ranged from –0.025 to 0.331 for E. coli and from –0.037 to 0.372 for total coliforms, showing no practical difference between the methods. The MC-Media Pad EC detected 49/50 E. coli and 60/63 coliform inclusivity strains and correctly excluded 30/32 exclusivity organisms for E. coli and 24/31 exclusivity organisms for total coliforms, which was similar to the reference method. Robustness testing demonstrated no significant change in results when small changes were made to sample volume, incubation temperature, and incubation time. The product consistency study demonstrated no significant difference between lots of product and supported the 1.5 year shelf life. Conclusions: The results support the conclusions that the MC-Media Pad EC is a suitable alternative to the ISO 4832:2006 and ISO 16649-2:2001 reference methods for the matrixes examined and the data support AOAC Performance Tested MethodSM certification. Highlights: The MC-Media Pad EC was approved for Performance Tested Method certification No. 011901.

scholarly journals Evaluation of the GENE-UP ®E. coli O157:H7 Method for the Detection of E. coli O157:H7 in Select Foods: Collaborative Study, 2019.03

2020 ◽  
Vol 103 (5) ◽  
pp. 1338-1347
Author(s):  
Ronald Johnson ◽  
John Mills ◽  
Jean-Louis Pittet ◽  
Maryse Rannou ◽  
Patrick Bird ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Collaborative Study ◽  
Control Level ◽  
Reference Method ◽  
Probability Of Detection ◽  
Contamination Level ◽  
Test Portion ◽  
E Coli ◽  
Significant Difference ◽  
Contamination Levels

Abstract Background The GENE-UP®E. coli O157:H7 2 (ECO 2) assay (Performance Tested MethodSM 121805) incorporates Fluorescence Resonance Energy Transfer hybridization probes into its proprietary PCR technology for the rapid detection of E. coli O157:H7 in select foods. Objective The purpose of this validation was to evaluate the method’s interlaboratory performance and submit the result to AOAC INTERNATIONAL for adoption as First Action Official MethodSM for the detection of E. coli O157:H7 in select foods. Method The GENE-UP® method was evaluated in a multi-laboratory study as part of the MicroVal validation process using unpaired test portions for one food matrix, raw milk cheese (Comté, 34% fat, 0.8% salt). The candidate method was compared to the ISO 16654:2001 reference method. Fourteen participants from 13 laboratories throughout the European Union participated. Three levels of contamination were evaluated: a non-inoculated control level (0 colony-forming units (CFU)/test portion), a low contamination level (∼5 CFU/test portion), and a high contamination level (∼10 CFU/test portion). Data from that study were analyzed according to the Probability of Detection (POD) statistical model as presented in the AOAC validation guidelines. The difference in laboratory POD (dLPODC) values with 95% confidence interval across collaborators was calculated for each level between the candidate and reference method results, and between the candidate presumptive and confirmed results. Results The dLPODC values with 95% confidence interval were; 0.00 (–0.04, 0.04), 0.27 (0.04, 0.49), and 0.17 (0.01, 0.33) for the non-inoculated, low and high contamination levels respectively. Conclusions The dLPODC results indicate a significant difference between the candidate method and the reference method for both the low and high contamination levels, with the candidate method producing higher recovery of the target organism at both levels. Highlights The GENE-UP E. coli O157:H7 assay provides industry with a rapid, accurate detection method for E. coli O157:H7 in a broad range of foods.

Evaluation of Coli-ID and MUG Plus media for recovering Escherichia coli and other coliform bacteria from groundwater samples

2001 ◽  
Vol 43 (12) ◽  
pp. 213-216 ◽  
Author(s):  
R. A. Sueiro ◽  
M. Araujo ◽  
C. J. Santos ◽  
M. J. Gómes ◽  
M. J. Garrido
Keyword(s):  
Escherichia Coli ◽  
Variance Analysis ◽  
Alternative Methods ◽  
Coliform Bacteria ◽  
Human Consumption ◽  
Recovery Efficiency ◽  
E Coli ◽  
Reference Methods ◽  
Groundwater Samples ◽  
Reference Medium

Several chromogenic media for detecting coliform bacteria in water are commercially available including Coli ID medium (ID) (bioMérieux) and MUG Plus cefsulodin agar (MP) (Laboratorios Microkit, S.L.). Since little is known about the performance of these media, we have evaluated their usefulness for recovering Escherichia coli and other coliform organisms in groundwaters used for direct human consumption. Variance analysis of obtained data showed that no statistically significant differences in counts of E. coli and other coliforms on ID and MP media compared with reference methods. However, the evaluation of sensitivity and recovery efficiency of both media showed that the two chromogenic media were more sensitive and significantly more efficient (P = ļ0.05) than reference medium for detecting coliforms in groundwater. However, the identification of 400 typical and atypical colonies isolated from ID and MP media demonstrated a higher specificity when using ID for coliforms and E. coli. In summary, the two chromogenic media evaluated could be used as alternative methods to reference media for detecting and recovering coliform bacteria in groundwater samples. MP agar was more sensitive and efficient than ID agar whereas the latter was more specific and selective.

Evaluation of the 3M™ Petrifilm™ Rapid Yeast and Mold Count Plate for the Enumeration of Yeast and Mold in Food: Collaborative Study, First Action 2014.05

2015 ◽  
Vol 98 (3) ◽  
pp. 767-783 ◽  
Author(s):  
Patrick Bird ◽  
Jonathan Flannery ◽  
Erin Crowley ◽  
James Agin ◽  
David Goins ◽  
...  
Keyword(s):  
Water Activity ◽  
Collaborative Study ◽  
Control Level ◽  
Culture Method ◽  
Colony Count ◽  
Contamination Level ◽  
Frozen Ground ◽  
Plate Method ◽  
Reference Methods ◽  
Significant Difference

Abstract The 3M™ Petrifilm™ Rapid Yeast and Mold (RYM) Count Plate is a simple, ready-to-use chromogenic culture method for the rapid detection and enumeration of yeast and mold in food products. The 3M Petrifilm RYM Count Plate method was compared to the U. S. Food and Drug Administration Bacteriological Analytical Manual (FDA BAM) Chapter 18, Yeasts, Molds and Mycotoxins and the ISO 21527:2008 Microbiology of Food and Animal Feeding Stuffs—Horizontal Method for the Enumeration for Yeast and Molds – Part 1: Colony Count Technique in Products with Water Activity Greater Than 0.95 and Part 2: Colony Count Technique in Products with Water Activity Less Than or Equal to 0.95 reference methods for raw almonds and raw frozen ground beef patties (77% lean). The 3M Petrifilm RYM Count Plate method was evaluated using a paired study design in a multi-laboratory collaborative study following the current AOAC Validation Guidelines. Three target contamination levels (low, 10–100 CFU/g; medium, 100–1000 CFU/g; high 1000–10 000 CFU/g) as well as an uninoculated control level (0 CFU/g) were evaluated for each matrix. Samples evaluated by the 3M Petrifilm RYM Count Plate method were prepared in duplicate and incubated at both 25°C and 28°C. Plates at both temperatures were enumerated after 48 and 60 h of incubation. No significant difference was observed between the 3M Petrifilm RYM Count Plate method and the FDA BAM or ISO 21527 reference methods for each contamination level. No statistical differences were observed between samples analyzed by the 3M Petrifilm RYM Count Plate method (at either 25°C or 28°C) and the reference methods. No statistical significant differences were observed between enumeration of colonies at 48 and 60 h on the 3M Petrifilm RYM Count Plate method and the reference methods.

Evaluation of the GENE-UP® EHEC Detection Method for the Detection of Enterohemorrhagic E. coli in Select Foods: Collaborative Study: First Action Method 2020.06

2021 ◽  
Author(s):  
Ronald Johnson ◽  
John Mills ◽  
Jean-Louis Pittet ◽  
Maryse Rannou ◽  
Patrick Bird
Keyword(s):  
Detection Method ◽  
Collaborative Study ◽  
False Negative ◽  
Control Level ◽  
Reference Method ◽  
Probability Of Detection ◽  
Contamination Level ◽  
Official Method ◽  
Test Portion ◽  
E Coli

Abstract Background The GENE-UP® EHEC assay (Performance Tested MethodSM 121806) is a real-time PCR molecular detection method that utilizes Fluorescence Resonance Energy Transfer proprietary hybridization probes for the rapid detection of Enterohemorrhagic E. coli (EHEC) in select foods. Objective The purpose of this validation was to evaluate the method’s interlaboratory performance and submit the results to AOAC INTERNATIONAL for adoption as First Action Official Method of AnalysisSM for the detection of EHEC in select foods. Method The GENE-UP® method was evaluated in a multi-laboratory study as part of the MicroVal VALIDATION certification process using unpaired test portions for one food matrix, raw ground beef (85% lean). Collaborators evaluated the candidate method using either an automated or manual lysis procedure. The candidate method was compared to the ISO/TS 13136:2012 method. Data from 17 participants from 15 laboratories throughout the European Union was evaluated. Three levels of contamination were evaluated: a non-inoculated control level (0 CFU/test portion), a low contamination level (∼1 CFU/test portion) and a high contamination level (∼10 CFU/test portion). Data from the study were analyzed according to the probability of detection (POD) statistical model. Results The dLPODC values with 95% confidence interval between the candidate and reference method results were; –0.01 (–0.04, 0.02), 0.23 (0.07, 0.39) and 0.06 (0.01, 0.12) for the non-inoculated, low and high contamination levels, respectively. Conclusion For the candidate method, values obtained for repeatability and reproducibility were similar to the reference method and indicated minimal variation between samples or between laboratories. No discrepant results (false positive or false negative) were observed for each contamination. A statistical difference was calculated between the candidate and reference method at the low and high inoculation levels, with the candidate method detecting a higher number of positive samples indicating a higher sensitivity than the reference method. No differences in the recovery of the target analyte were observed between the manual and automated lysis procedures. Highlights The GENE-UP EHEC Detection Method provides end users a rapid, easy-to-use workflow for the detection of EHEC in food matrices.

Bacteriophages reduce Escherichia coli O157:H7 levels in experimentally inoculated sheep

2009 ◽  
Vol 89 (2) ◽  
pp. 285-293 ◽  
Author(s):  
S J Bach ◽  
R P Johnson ◽  
K. Stanford ◽  
T A McAllister
Keyword(s):  
Escherichia Coli ◽  
Oral Administration ◽  
Coliform Bacteria ◽  
Escherichia Coli O157 ◽  
Fecal Shedding ◽  
Total Coliforms ◽  
E Coli ◽  
Oral Inoculation ◽  
Experimental Treatments ◽  
And Control

Bacteriophage biocontrol has potential as a means of mitigating the prevalence of Escherichia coli O157:H7 in ruminants. The efficacy of oral administration of bacteriophages for reducing fecal shedding of E. coli O157:H7 by sheep was evaluated using 20 Canadian Arcott rams (50.0 ± 3.0) housed in four rooms (n = 5) in a contained facility. The rams had ad libitum access to drinking water and a pelleted barley-based total mixed ration, delivered once daily. Experimental treatments consisted of administration of E. coli O157:H7 (O157), E. coli O157:H7+bacteriophages (O157+phage), bacteriophages (phage), and control (CON). Oral inoculation of the rams with 109 CFU of a mixture of four nalidixic acid-resistant strains of E. coli O157:H7 was performed on day 0. A mixture of 1010 PFU of bacteriophages P5, P8 and P11 was administered on days -2, -1, 0, 6 and 7. Fecal samples collected on 14 occasions over 21 d were analyzed for E. coli O157:H7, total E. coli, total coliforms and bacteriophages. Sheep in treatment O157+phage shed fewer (P < 0.05) E. coli O157:H7 than did sheep in treatment O157. Populations of total coliforms and total E. coli were similar (P < 0.05) among treatments, implying that bacteriophage lysis of non-target E. coli and coliform bacteria in the gastrointestinal tract did not occur. Bacteriophage numbers declined rapidly over 21 d, which likely reduced the chance of collision between bacteria and bacteriophage. Oral administration of bacteriophages reduced shedding of E. coli O157:H7 by sheep, but a delivery system that would protect bacteriophages during passage through the intestine may increase the effectiveness of this strategy as well as allow phage to be administered in the feed.Key words: Escherichia coli O157:H7, bacteriophage, sheep, environment, coliforms

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