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

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.

2019 ◽  
Vol 102 (5) ◽  
pp. 1492-1501
Author(s):  
Hajime Teramura ◽  
Aya Ogura ◽  
Linda Everis ◽  
Gail Betts

Abstract Background: Standard coliform count methods require the preparation of agar, the use of the 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 CC for the enumeration of 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 CC was compared to standard method ISO 4832:2006 for 10 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. Methods: Each matrix was tested at three levels of coliform 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 CC and ISO 4832:2006 methods. In addition, inclusivity/exclusivity, robustness, and product consistency and stability were evaluated. Results: The candidate and reference methods demonstrated SDs ranging from 0.027 to 0.264 and 0.025 to 0.157, respectively. The difference of means ranged from –0.015 to 0.381, showing no practical difference between the methods. The MC-Media Pad CC detected 58/62 inclusivity strains and correctly excluded 26/31 exclusivity organisms, 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 CC is a suitable alternative to the ISO 4832:2006 reference method for the matrixes examined and the data support AOAC Performance Tested MethodSM certification.


1991 ◽  
Vol 54 (4) ◽  
pp. 246-248 ◽  
Author(s):  
MILES L. MOTES ◽  
JAMES T. PEELER

Oysters and seawater collected from the southeastern United States were examined for fecal coliforms and Escherichia coli, using the current procedure of the American Public Health Association (APHA) and the fluorogenic 4-methylumbelliferyl-β-D-glucuronide (MUG) modified APHA procedure. After the presence of E. coli in both methods was confirmed by conventional IMViC procedures, there was no significant difference between method means at the α = 0.05 level. In oysters, low confirmation rates of 67 and 77% were observed by the APHA and the MUG methods, respectively. Seawater had the greatest confirmation rates (95%) by the MUG method. The MUG method may be a suitable alternative to the current APHA method for the microbiological evaluation of oysters and seawater.


2012 ◽  
Vol 95 (6) ◽  
pp. 1656-1668 ◽  
Author(s):  
Jun Li ◽  
Win Den Cheung ◽  
Jason Opdyke ◽  
John Harvey ◽  
Songchun Chong ◽  
...  

Abstract Salmonella, one of the most common causes of foodborne illness, is a significant public health concern worldwide. There is a need in the food industry for methods that are simple, rapid, and sensitive for the detection of foodborne pathogens. In this study, the Samsung Salmonella Detection Kit, a realtime PCR assay for the detection of Salmonella, was evaluated according to the current AOAC guidelines. The validation consisted of lot-to-lot consistency, stability, robustness, and inclusivity/exclusivity studies, as well as a method comparison of 10 different food matrixes. In the validation, the Samsung Salmonella Detection Kit was used in conjunction with the Applied Biosystems StepOnePlus™ PCR system and the Samsung Food Testing Software for the detection of Salmonella species. The performance of the assays was compared to the U.S. Department of Agriculture/Food Safety and Inspection Service-Microbiology Laboratory Guidebook (USDA/FSIS-MLG) 4.05: Isolation and Identification of Salmonella from Meat, Poultry, Pasteurized Egg, and Catfish and the and U.S. Food and Drug Administration/Bacteriological Analytical Manual (FDA/BAM) Chapter 5 Salmonella reference methods. The validation was conducted using an unpaired study design for detection of Salmonella spp. in raw ground beef, raw pork, raw ground pork, raw chicken wings, raw salmon, alfalfa sprouts, pasteurized orange juice, peanut butter, pasteurized whole milk, and shell eggs. The Samsung Salmonella Detection Kit demonstrated lot-to-lot consistency among three independent lots as well as ruggedness with minor modifications to changes in enrichment incubation time, enrichment incubation temperature, and DNA sample volume for PCR reaction. Stability was observed for 13 months at –20°C and 3 months at 5°C. For the inclusivity/exclusivity study, the Samsung Salmonella Detection Kit correctly identified 147 Salmonella species isolates out of 147 isolates tested from each of three different enrichment broths (a total of 441 isolates detected), and correctly excluded all 31 nontarget strains analyzed. For the method comparison, statistical analysis was conducted according to the Mantel-Haenszel Chi-square formula for unpaired test portions, and there was no significant difference in the number of positive samples detected between the Samsung Salmonella Detection Kit and the USDA/FSIS-MLG and FDA/BAM reference methods for all 10 food matrixes.


2018 ◽  
Vol 101 (2) ◽  
pp. 456-467
Author(s):  
Hajime Teramura ◽  
Gail Betts ◽  
Yi Chen ◽  
Michael Brodsky ◽  
Yvonne Salfinger

Abstract MC-Media Pad SA (formerly known as Sanita-kun SA) is a dry rehydratable film medium for the enumeration of Staphylococcus aureus. The performance of the method in a variety of foods was compared with that of ISO 6888-1:1999, Microbiology of Food and Animal Feeding Stuffs - Horizontal Method for the Enumeration of Coagulase-Positive Staphylococci (Staphylococcus aureus and Other Species) - Part 1: Technique Using Baird–Parker Agar Medium. The validated matrixes included pastrami, a sliced cooked chicken roll, cooked prawns, cold-smoked salmon, pasta salad, sandwich spread, fresh uncooked pasta, infant cereal, custard, and raw-milk Brie cheese. In the matrix study, five replicates at each of three contamination levels were tested as paired test portions. Across all matrixes, the difference in mean log10 values ranged from –0.32 to 0.10, which was within the acceptable range of –0.50 to 0.50. Thus, all 10 matrixes met the acceptance criterion at all concentration levels. Further, only two matrixes, cooked prawns and raw-milk Brie cheese, had 95% confidence limits outside the –0.50 to 0.50 criterion, and these were at the lowest concentration level for each matrix. The candidate method sr varied from 0.03 to 0.22 log10 CFU/g. This compares favorably with the reference method SD, which ranged from 0.06 to 0.30 log10 CFU/g. The candidate and reference methods detected 51 of 53 inclusivity strains, with both methods not detecting the same two strains. The candidate method did not detect any of the 32 exclusivity strains, whereas the reference method did not detect 30 of the 32 exclusivity strains; the 2 strains detected by the reference method were S. delphini and S. hyicus, both developing atypical colonies on Baird–Parker plates. The product consistency study demonstrated no significant difference between lots of product and supported the 1 year shelf life. Robustness testing yielded no significant differences when small variations were made in sample volume, incubation temperature, and incubation time. Thus, the data show equivalent or better performance of the Sanita-kun SA/MC-Media Pad SA method compared with the International Organization for Standardization reference method, in support of AOAC Performance Tested MethodSM certification.


2014 ◽  
Vol 4 (4) ◽  
pp. 604-611
Author(s):  
Amanda S. Brand ◽  
Jo M. Barnes

The increase in numbers and contamination levels of faecally polluted water has resulted in shifts worldwide towards methods which enumerate faecal indicator bacteria faster. Rapid methods enable more timely remedial and preventative actions which protect the health of water users. However, especially in the developing world, straightforward methods are also preferred as they reduce the requirement for highly qualified analysts. This study investigates the feasibility of using the rapid, semi-automated enzyme substrate test Colilert-18® instead of multiple-tube fermentation (MTF) in total coliform and Escherichia coli enumeration for South African river water, as one example of a surface water source carrying considerable faecal pollution, which needs monitoring. Spearman rank correlation coefficients (ρ) of 0.83 and 0.86 were obtained for total coliforms and E. coli respectively, indicating Colilert-18® performed acceptably in the pollution ranges encountered. A Bland–Altman plot further revealed that Colilert-18® showed no significant difference (p > 0.05) from MTF values below 100,000 E. coli most probable number/100 mL (estimated true value). Above this level Colilert-18® was found to progressively underestimate E. coli. This inadequacy of Colilert-18® was considered acceptable from a health risk assessment viewpoint as such high counts should have sounded the alarm for preventative and corrective action irrespective of method inaccuracy.


2020 ◽  
Vol 8 (1) ◽  
pp. 134-140
Author(s):  
Abdolghani Ameri ◽  
Maryam Ekhtelat ◽  
Sara Shamsaei

Introduction. Medicinal herbs are susceptible to microbial contamination which can have profound effects on the consumer’s health. Our study aimed to evaluate microbial contamination of common medicinal herbs in Ahvaz. Study objects and methods. We collected 80 samples of traditional and industrial medicinal plants from the supply market, namely valeriana, fennel, licorice, and shirazi thyme. The reference method was used to determine microbial indices such as the total count of microorganisms, yeast and mold, Bacillus cereus, coliforms, and Escherichia coli. Results and discussion. We found that the total microbial count, yeast and mold, B. cereus, and coliform contamination accounted for 45, 77, 55, and 55% of the total samples, respectively, exceeding the allowed limits. There was a significant difference between the industrial and traditional samples in fungal and coliform contamination, with the traditional samples being more highly contaminated. However, no significant difference was observed between them in total count and B. cereus contamination. E. coli contamination was detected in 31.2% of the samples, mostly in traditional. Total microbial count and yeast and mold contamination were highest among valeriana plants. Fennel showed the highest B. cereus and coliform contamination. The lowest contamination was observed in licorice. Conclusion. The results showed that a considerable percentage of the medicinal herbs under study were contaminated at levels exceeding the standard limits. Plants could be contaminated during harvesting, processing or storage. Finally, different species of plants have different antimicrobial activities that affect their microbial contamination.


2020 ◽  
Vol 103 (2) ◽  
pp. 513-522
Author(s):  
Patrick Bird ◽  
Benjamin Bastin ◽  
Nicole Klass ◽  
Erin Crowley ◽  
James Agin ◽  
...  

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.


2019 ◽  
Vol 102 (5) ◽  
pp. 1455-1471
Author(s):  
Benjamin Bastin ◽  
Leo Horine ◽  
Patrick Bird ◽  
M Joseph Benzinger ◽  
James Agin ◽  
...  

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.


1984 ◽  
Vol 67 (4) ◽  
pp. 812-823
Author(s):  
Phyllis Entis ◽  
◽  
B Bennett ◽  
M H Brodsky ◽  
D M Burgener ◽  
...  

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.


2018 ◽  
Vol 101 (3) ◽  
pp. 769-782 ◽  
Author(s):  
Hajime Teramura ◽  
Gail Betts ◽  
Yi Chen ◽  
Michael Brodsky ◽  
Yvonne Salfinger

Abstract The MC-Media Pad ACplus™ is a dry, rehydratable film medium for the enumeration of aerobic bacterial colonies. The performance of the method in a variety of foods was compared to that of U.S. reference methods: U.S. Department of Agriculture (USDA) Food Safety and Inspection Service (FSIS) Microbiology Laboratory Guidebook (MLG) Chapter 3.02 “Quantitative Analysis of Bacteria in Foods as Sanitary Indicators” (USDA/FSIS MLG 3.02); Standard Methods for the Examination of Dairy Products (SMEDP) Chapter 6 “Microbiological Count Methods, Standard Plate Count Method” (SMEDP 6); AOAC Official MethodSM966.23Microbiological Methods; and ISO 4833-1:2013 “Microbiology of the food chain—Horizontal method for the enumeration of microorganisms—Part 1: Colony count at 30 degrees C by the pour plate technique.” The validated matrixes included raw chicken breast and raw ground pork for USDA/FSIS MLG 3.02; cream cheese and yogurt drink for SMEDP 6; parsley, vegetable juice, prawns, tuna pate, sandwiches, and pasta salad for AOAC Method 966.23, and raw chicken breast, raw ground pork, cream cheese, yogurt drink, parsley, vegetable juice, prawns, tuna pate, sandwiches, and pasta salad for ISO 4833-1:2013. In each matrix study, five replicates at each of three contamination levels were tested as paired test portions. All 10 matrixes were compared to the appropriate U.S. reference methods under MC-Media Pad ACplus standard-usage conditions (35 ± 1°C for 48 ± 2 h). Across all matrixes, the difference of mean log10 values ranged from –0.43 to 0.44, within the acceptable range of –0.50 to 0.50. The candidate method repeatability SD (sr) varied from 0.03 to 0.23 log10 CFU/g, comparing favorably to the reference method SD, which ranged from 0.06 to 0.30 log10 CFU/g. Seven matrixes were compared to the appropriate U.S. reference methods under MC-Media Pad ACplus rapid-usage conditions (35 ± 1°C for 24 ± 2 h). Of the 21 matrix/concentration combinations, only three instances of difference of mean >0.5 log were observed. The ranges of sr values of the rapid-usage candidate method (0.023–0.324) and the reference method (0.013–0.236) were similar for the seven matrixes tested. All 10 matrixes were compared to the International Organization for Standardization (ISO) reference method under MC-Media Pad ACplus alternate-method conditions (30 ± 1°C for 72 ± 3 h). All 10 matrixes yielded a mean difference between methods of <0.5 log, and the ranges of sr values were similar between the candidate alternate method (0.037–0.378) and the ISO reference method (0.037–0.437). The product consistency study demonstrated no significant difference between lots of product and supported the 2-year shelf life. Robustness testing yielded no significant differences when small variations were made in sample volume, incubation temperature, and incubation time. Thus, the data show equivalent or better performance of the MC-Media Pad ACplus method compared to the relevant reference methods in support of AOAC Performance Tested MethodSM certification.


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