Comparison of 3M™ Petrifilm™ Aerobic Count Plates to Standard Plating Methodology for Use with AOAC Antimicrobial Efficacy Methods 955.14, 955.15, 964.02, and 966.04 as an Alternative Enumeration Procedure: Collaborative Study

2013 ◽  
Vol 96 (4) ◽  
pp. 717-722 ◽  
Author(s):  
Maria T Nelson ◽  
Robert A LaBudde ◽  
Stephen F Tomasino ◽  
Rebecca M Pines ◽  
M Bennett ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Test Methods ◽  
Antimicrobial Efficacy ◽  
Plate Count ◽  
Matched Pair ◽  
Acceptance Criterion ◽  
Standard Plate Count ◽  
Test Organisms ◽  
Standard Plate ◽  
Viable Bacteria

Abstract A multilaboratory study was conducted to determine the equivalence of the 3M™ Petrifilm™ Aerobic Count Plate and standard plating methodology for measuring viable bacteria and spores recovered from hard-surface carriers (stainless steel and porcelain), also known as "control carrier counts," used in AOAC antimicrobial efficacy test methods. Six laboratories participated in the study in which carriers inoculated with Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, and spores of Bacillus subtilis were evaluated using 3M Petrifilm Aerobic Count (AC) plates and standard plating side-by-side. The data were analyzed using a matched-pair t-test to determine the between-method effect with confidence intervals. For all test organisms pooled across all laboratories, the mean difference in log10 concentration between the standard plate count method and 3M Petrifilm AC Plates was −0.012, with a 95% confidence interval of (−0.090, +0.066), which was well within the −0.5, +0.5 interval established as the acceptance criterion. The between-carrier SD averaged 0.139; the between-replicate SD was 0.050. The carrier reproducibility, given that a single replicate per carrier is done, was estimated to be 0.148. Although differences were seen in the final concentrations of the test organisms among laboratories, there were no statistical differences between the enumeration methods. Based on the results from this study, 3M Petrifilm AC Plates are equivalent to standard plating methodology and can be used as an alternative procedure for the enumeration of test organisms used in AOAC Methods 955.14, 955.15, 964.02, and 966.04.

Collaborative Study of the Impedance Method for Examining Raw Milk Samples

1984 ◽  
Vol 47 (9) ◽  
pp. 707-712 ◽  
Author(s):  
R. FIRSTENBERG-EDEN
Keyword(s):  
Collaborative Study ◽  
Raw Milk ◽  
Plate Count ◽  
Impedance Method ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Automated Method ◽  
Significant Difference ◽  
Standard Plate ◽  
Contamination Levels

The impedance method is a rapid automated method for determining bacteriological contamination levels. A collaborative study was done to establish the reproducibility of the impedance method in predicting counts of raw milk. Frozen and unfrozen raw milk samples, with counts in the range of 9 × 104 to 4 × 107 CFU/ml, were sent to six laboratories to be examined by the standard plate count method (SPC) and by the impedance method which produced Bactometer-predicted counts (BPC). The impedance results showed less variability than SPC among laboratories in all three trials. The variance between split samples was also smaller for the impedance method than for SPC. However, the variance between duplicate plates of the same sample was significantly smaller for SPC than for BPC. In one trial, the means of BPC and SPC were not significantly different, whereas in another trial there was a significant difference of ca. log10 0.27 between the means of the two methods. However, in this trial the extreme differences between laboratories counting the same sample were log10 0.42.

scholarly journals Microbiological Profile of the Traditionally Collected Industrial Raw Milk from the Milk Pocket Zones of Bangladesh

1970 ◽  
Vol 25 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Gouranga C Chanda ◽  
Gazi M Noor Uddin ◽  
Aparna Deb ◽  
Tahmina Bilkis ◽  
Sharmin Chowdhury ◽  
...  
Keyword(s):  
Bacterial Count ◽  
Raw Milk ◽  
Total Coliform ◽  
Plate Count ◽  
Coliform Count ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Bacteriological Profile ◽  
Standard Plate ◽  
Viable Bacteria

The study was aimed to evaluate the bacteriological profile of the traditionally collected industrial raw milk from the milk pocket zones of Bangladesh. About 365 raw milk samples were collected from the milk tanker, who brought raw milk from the mother chilling centre where raw milk was chilled at 4°C following traditional method. All milk samples were subjected to perform standard plate count and total coliform count. The average standard plate count was found to be 4.37 x 106 cfu/ml and the highest occurrence of standard plate count was found to be 6.70 x 106 cfu/ml in October and the lowest (3.28 x 106 cfu/ml) in March. The highest occurrence of total viable bacteria was found to be 5.64 x 106 cfu/ml in autumn and the lowest was found to be 3.78 x 106 cfu/ml in summer. On the other hand, the average of the coliform bacterial count was found to be 3.88 x 105 cfu/ml with the highest (5.70 x 105 cfu/ml) occurrence in May and the lowest (1.90 x 105 cfu/ml) in January. Moreover, the highest occurrence of coliform count was found to be 4.84 x 105 cfu/ml in rainy season and the lowest was 2.75 x 105 cfu/ml found in winter.DOI: http://dx.doi.org/10.3329/bjm.v25i1.4849 Bangladesh J Microbiol, Volume 25, Number 1, June 2008, pp 17-20

Evaluation of a Membrane Filter Test Kit for Monitoring Bacterial Counts in Cannery Cooling Waters

1982 ◽  
Vol 45 (12) ◽  
pp. 1087-1090 ◽  
Author(s):  
C. R. REY ◽  
G. A. HALABY ◽  
E. V. LOVGREN ◽  
T. A. WRIGHT
Keyword(s):  
Standard Method ◽  
Membrane Filter ◽  
Plate Count ◽  
Bacterial Counts ◽  
Standard Plate Count ◽  
Test Kit ◽  
Standard Plate ◽  
Viable Bacteria ◽  
Plate Count Method ◽  
Filter Test

Performance of the Millipore SPC Sampler was compared with the Standard Plate count method for routine checks of bacterial counts in cannery cooling waters. Methods were tested with cooling waters from a hydrostatic retort. Recovery of viable bacteria was very low when the Millipore samples were incubated for 24 h, but incubation for 48 or 72 h consistently yielded higher counts with the Millipore than with the standard method. Duplication of counts between analysts was approximately equal with both methods. Replication of bacterial counts within samples was more erratic and skips were more frequent with the Millipore than with the standard method. Procedures to control replications and skips are discussed. The Millipore procedure is a convenient alternative to the Standard Plate Count for routine quality audit of cannery cooling waters.

Enumeration of Total Bacteria in Raw and Pasteurized Milk by Reflectance Colorimetry: Collaborative Study

1994 ◽  
Vol 77 (3) ◽  
pp. 623-627 ◽  
Author(s):  
Gary H Richardson ◽  
James T C Yuan ◽  
Donald V Sisson ◽  
Barry O Stokes
Keyword(s):  
Collaborative Study ◽  
Plate Count ◽  
Pasteurized Milk ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Total Bacteria

Abstract Seven out of 9 laboratories completed a collaborative study comparing a reflectance colorimetric (RC) bioactivity monitor (Omnispec™ 4000) method to the standard plate count (SPC) method for estimation of total bacteria in raw and homogenized pasteurized milk. Each laboratory analyzed 12 different samples by the SPC method and 24 samples (12 blind duplicates) by the RC method. For the RC method RSDr was 1.7%, and RSDR was 4.5%. RSDR for the SPC method was 20.8%. The method was adopted first action by AOAC INTERNATIONAL.

Enumeration of Total Bacteria and Coliforms in Milk by Dry Rehydratable Film Methods: Collaborative Study

1986 ◽  
Vol 69 (3) ◽  
pp. 527-531 ◽  
Author(s):  
Roy E Ginn ◽  
Vernal S Packard ◽  
Terrance L Fox ◽  
◽  
E Arnold ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Plate Count ◽  
Standard Methods ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate ◽  
The Mean ◽  
Standard Deviations ◽  
The Difference ◽  
Total Bacteria

Abstract Eleven laboratories participated in a collaborative study to compare the dry rehydratable film (Petrifilm® SM and Petrifilm® VRB) methods, respectively, to the standard plate count (SPC) and violet red bile agar (VRBA) standard methods for estimation of total bacteria and coliform counts in raw and homogenized pasteurized milk. Each laboratory analyzed 16 samples (8 different samples in blind duplicate) for total count by both the SPC and Petrifilm SM methods. A second set of 16 samples was analyzed by the VRBA and Petrifilm VRB methods. The repeatability standard deviations (the square root of the between-replicates variance) of the SPC, Petrifilm SM, VRBA, and Petrifilm VRB methods were 0.0S104, 0.0444, 0.14606, and 0.13806, respectively; the reproducibility standard deviations were 0.7197, C.06380, 0.15326, and 0.13806, respectively. The difference between the mean Iog10 SPC and the mean logio Petrifilm SM results was 0.027. For the VRBA and Petrifilm VRB methods, the mean log10 difference was 0.013. These results generally indicate the suitability of the dry rehydratable film methods as alternatives to the SPC and VRBA methods for milk samples. The methods have been adopted official first action.

A Collaborative Study of the Spiral Plate Method for Examining Milk Samples

1977 ◽  
Vol 40 (7) ◽  
pp. 462-464 ◽  
Author(s):  
J. T. PEELER ◽  
J. E. GILCHRIST ◽  
C. B. DONNELLY ◽  
J. E. CAMPBELL
Keyword(s):  
Collaborative Study ◽  
Raw Milk ◽  
Plate Count ◽  
Milk Analysis ◽  
Milk Chocolate ◽  
Components Of Variance ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate ◽  
Spiral Plate

The spiral plating procedure is a rapid method for determining bacteriological counts. Results from a collaborative study indicate that the procedure should be useful in milk analysis. Typical milk samples (homogenized milk, raw milk, chocolate drink, 2% milk, and 20% cream) were sent to six analysts to be examined by standard plate count (SPC) and spiral plate count (SPLPC). Analysis of duplicate samples shows that the SPC and SPLPC values did not differ at the a = 0.01 level. Components of variance for replicate determinations among laboratories and laboratory-sample interaction were computed. The standard deviation was 0.109 compared to the 0.110 estimate reported for SPC in state laboratories. Results from the SPLPC method compared favorably to the results of conventional (SPC) pour procedure.

Automated Technique for Sampling Milk from Farm Bulk Tanks: Collaborative Study

1993 ◽  
Vol 76 (2) ◽  
pp. 297-305
Author(s):  
Vernal S Packard ◽  
Roy E Ginn ◽  
Dick T Metzger
Keyword(s):  
Collaborative Study ◽  
Microbiological Quality ◽  
Plate Count ◽  
Sampling Device ◽  
Entire Volume ◽  
Psychrotrophic Bacteria ◽  
Standard Plate Count ◽  
Automated Method ◽  
Standard Plate ◽  
Automated Technique

Abstract An automated, in-line, mechanical technique for sampling milk from farm bulk tanks was evaluated in a collaborative study. The automated sampling device, which is mounted on the milk intake line, contains an electronically controlled peristaltic pump. The device takes a representative sample of the entire volume pumped through the system. Samples taken can be analyzed for both composition and microbiological quality. The study was performed in 3 phases. In the first 2 phases, samples taken by manual and automated methods were compared in analyses for somatic cell count, antibiotics, fat, protein, lactose, and solids-not-fat. The third phase, using a modified procedure, was designed to compare sampling methods in analyses for total bacteria count (standard plate count), psychrotrophic bacteria count, and coliform count. Evaluation of the data by a nested ANOVA indicated no difference between results for samples taken by the automated and manual methods (P = 0.05) in Phases 1 and 2, irrespective of whether the bulk milk was agitated before sampling. By introducing a sanitizing step between farms in Phase 3, the automated method also provided samples comparable with those taken manually for microbial analyses. The automated method has been adopted first action by AOAC International.

EFFECT OF THE TYPE OF BACTERIOLOGICAL PEPTONE IN THE PLATING MEDIUM UPON THE ENUMERATION OF PASTEURIZATION-RESISTANT BACTERIA IN MILK1

1966 ◽  
Vol 29 (6) ◽  
pp. 182-186 ◽  
Author(s):  
W. R. Thomas ◽  
G. W. Reinbold ◽  
F. E. Nelson
Keyword(s):  
Raw Milk ◽  
Plate Count ◽  
Colony Development ◽  
Resistant Bacteria ◽  
Pasteurized Milk ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Viable Bacteria

Summary Various bacteriological, peptones were studied as to effects on enumeration of pasteurization-resistant bacteria in milk. No appreciable differences were observed in colony counts of unheated cultures of thermoduric Micrococcus varians and Arthrobacter and Streptococcus sp. when plated with media containing different peptones. After laboratory pasteurization, colony counts differed substantially. Usually, media producing the highest counts yielded the largest and most easily discernible colonies. Bacto-Tryptone was deficient for colony development of thermoduric streptococci. Results indicate that, although seemingly adequate for enumeration in raw milk, the bacteriological peptone currently recommended for the standard plate count may not be satisfactory for the determination of the maximum viable bacteria population of pasteurized milk.

EFFECT OF pH OF PLATING MEDIUM ON ENUMERATION OF PASTEURIZATION-RESISTANT BACTERIA IN MILK1

1966 ◽  
Vol 29 (5) ◽  
pp. 156-160 ◽  
Author(s):  
W. R. Thomas ◽  
G. W. Reinbold ◽  
F. E. Nelson
Keyword(s):  
Heat Treatment ◽  
Raw Milk ◽  
Plate Count ◽  
Resistant Bacteria ◽  
Medium Ph ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Pure Cultures ◽  
Viable Bacteria

Summary Plating media of different pH were studied as to effects on enumeration of pasteurization-resistant bacteria in milk. After heat treatment, thermoduric bacteria were more tolerant of pH levels above rather than below 7, and maximum mean thermoduric counts were obtained at pH 7.5. There were some exceptions, but usually the pH levels that yielded the highest counts also produced the largest and most easily discernible colonies. Pure cultures of thermoduric bacteria grew over a much wider range of pH before than they did after laboratory pasteurization. Results indicate that, although seemingly adequate for enumeration in raw milk, the medium pH currently recommended for the standard plate count may not be satisfactory for the determination of the maximum viable bacteria population of pasteurized milk.

Evaluation of the 3M™ Petrifilm™ Rapid Aerobic Count Plate for the Enumeration of Aerobic Bacteria: Collaborative Study, First Action 2015.13

2016 ◽  
Vol 99 (3) ◽  
pp. 664-675
Author(s):  
Patrick Bird ◽  
Jonathan Flannery ◽  
Erin Crowley ◽  
James Agin ◽  
David Goins ◽  
...  
Keyword(s):  
Collaborative Study ◽  
Skim Milk ◽  
Plate Count ◽  
Aerobic Bacteria ◽  
Contamination Level ◽  
Standard Plate Count ◽  
Dual Sensor ◽  
Standard Plate ◽  
Aerobic Plate Count ◽  
Contamination Levels

Abstract The 3M™ Petrifilm™ Rapid Aerobic Count (RAC) Plate is a sample-ready culture medium system containing dual-sensor indicator technology for the rapid quantification of aerobic bacteria in food products. The 3M Petrifilm RAC Plate was compared to the U.S. Food and Drug Administration Bacteriological Analytical Manual (FDA BAM) Chapter 3 (Aerobic Plate Count) for the enumeration of aerobic bacteria in raw easy-peel shrimp and the Standard Methods for the Examination of Dairy Products (SMEDP) Chapter 6 (Standard Plate Count Method) for the enumeration of aerobic bacteria in pasteurized skim milk and instant nonfat dry milk (instant NFDM). The 3M Petrifilm RAC Plate was evaluated using a paired study design in a multilaboratory collaborative study following current AOAC validation guidelines. Three target contamination levels (low, 10–100 CFU/g; medium, 100–1000 CFU/g; and high 1000–10 000 CFU/g) were evaluated for naturally occurring aerobic microflora for each matrix. For raw easy-peel shrimp, duplicate 3M Petrifilm RAC Plates were enumerated after 24 ± 2 h incubation at both 32 and 35°C. Pasteurized skim milk 3M Petrifilm RAC Plates were enumerated after 24 ± 2 h incubation at 32°C, and instant NFDM 3M Petrifilm RAC Plates were enumerated after 48 ± 3 h incubation at 32°C. No statistical difference was observed between 3M Petrifilm RAC Plate and FDA BAM or SMEDP reference methods for each contamination level.

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