Rapid estimation of most probable number with a hand-held calculator

1983 ◽  
Vol 29 (5) ◽  
pp. 621-623 ◽  
Author(s):  
M. T. MacDonell
Keyword(s):  
Rapid Method ◽  
Environmental Samples ◽  
Most Probable Number ◽  
Probable Number ◽  
Rapid Estimation ◽  
Dilution Level

The most probable number (MPN) method of enumerating bacteria from environmental samples is widely used; however, it requires (i) that only certain numbers of tubes per dilution level be employed and (ii) a table of MPN values by which the resulting MPN codes may be evaluated. A rapid method for the estimation of MPN, regardless of the number of tubes per dilution level, applicable to unsophisticated hand-held calculators is presented.

scholarly journals Microbial contamination including Vibrio cholerae in fishery auction markets in West Sea, South Korea

2019 ◽  
Vol 22 (1) ◽  
Author(s):  
Yukyung Choi ◽  
Yewon Lee ◽  
Soomin Lee ◽  
Sejeong Kim ◽  
Jeeyeon Lee ◽  
...  
Keyword(s):  
Vibrio Cholerae ◽  
Environmental Samples ◽  
Sea Bass ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Pcr Analysis ◽  
Probable Number ◽  
Auction Markets ◽  
E Coli ◽  
Fishery Products

Abstract Background The monitoring of pathogens of fishery auction markets is important to obtain safe fishery products regarding hygiene and sanitation. In this study, aerobic, coliform, Escherichia coli, and Vibrio cholerae were monitored in the fishery products and environmental samples obtained from fishery auction markets. Methods The fishery products (flounder, octopus, skate, rock cod, sea bass, snail, monkfish, flatfish, comb pen shell, corb shell, conger eel, hairtail, croaker, and pilchard) were placed in filter bags, and the environmental samples (samples from the water tanks at the fishery auction markets, seawater from the fishery distribution vehicles, ice from wooden or plastic boxes, and surface samples from wooden and plastic boxes used for fish storage) were collected. Aerobic bacteria, E. coli, and coliform in the samples were enumerated on aerobic count plates and E. coli/coliform count plates, respectively. For V. cholerae O1 and V. cholerae non-O1 quantification, most probable number (MPN)-PCR analysis was performed. Results Aerobic and coliform bacteria were detected in most samples, but E. coli was not detected. Wooden boxes were contaminated with high levels of aerobic and coliform bacteria in all seasons (spring, summer, and fall). During fall, V. cholerae non-O1 were detected in snails, hairtails, croakers, flatfishes, pilchards, plastic boxes, and water samples. Conclusions These results indicate an increased prevalence of V. cholerae contamination in fishery products in fall, including food contact samples, which can be vehicles for cross-contamination.

Coliforms, Escherichia coli and Salmonella Serovars Associated with a Citrus-Processing Facility Implicated in a Salmonellosis Outbreak†

1998 ◽  
Vol 61 (3) ◽  
pp. 280-284 ◽  
Author(s):  
MICKEY E. PARISH
Keyword(s):  
Escherichia Coli ◽  
Environmental Samples ◽  
Fecal Coliforms ◽  
Most Probable Number ◽  
Probable Number ◽  
Bufo Terrestris ◽  
Processing Facility ◽  
Salmonella Serovars ◽  
Enrichment Techniques ◽  
Fruit Surface

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).

Improved Most-Probable-Number Method To Detect Sulfate-Reducing Bacteria with Natural Media and a Radiotracer

1998 ◽  
Vol 64 (5) ◽  
pp. 1700-1707 ◽  
Author(s):  
Flemming Vester ◽  
Kjeld Ingvorsen
Keyword(s):  
Sulfate Reduction ◽  
Environmental Samples ◽  
Sulfate Reducing Bacteria ◽  
Most Probable Number ◽  
Probable Number ◽  
Sulfate Reducing ◽  
Sulfate Reduction Rates ◽  
Synthetic Media ◽  
Reducing Bacteria ◽  
Natural Media

ABSTRACT A greatly improved most-probable-number (MPN) method for selective enumeration of sulfate-reducing bacteria (SRB) is described. The method is based on the use of natural media and radiolabeled sulfate (35SO4 2−). The natural media used consisted of anaerobically prepared sterilized sludge or sediment slurries obtained from sampling sites. The densities of SRB in sediment samples from Kysing Fjord (Denmark) and activated sludge were determined by using a normal MPN (N-MPN) method with synthetic cultivation media and a tracer MPN (T-MPN) method with natural media. The T-MPN method with natural media always yielded significantly higher (100- to 1,000-fold-higher) MPN values than the N-MPN method with synthetic media. The recovery of SRB from environmental samples was investigated by simultaneously measuring sulfate reduction rates (by a35S-radiotracer method) and bacterial counts by using the T-MPN and N-MPN methods, respectively. When bacterial numbers estimated by the T-MPN method with natural media were used, specific sulfate reduction rates (qSO4 2−) of 10−14to 10−13 mol of SO4 2−cell−1 day−1 were calculated, which is within the range of qSO4 2− values previously reported for pure cultures of SRB (10−15 to 10−14 mol of SO4 2− cell−1day−1). qSO4 2− values calculated from N-MPN values obtained with synthetic media were several orders of magnitude higher (2 � 10−10 to 7 � 10−10 mol of SO4 2−cell−1 day−1), showing that viable counts of SRB were seriously underestimated when standard enumeration media were used. Our results demonstrate that the use of natural media results in significant improvements in estimates of the true numbers of SRB in environmental samples.

Estimation of Methanogen Biomass by Quantitation of Coenzyme M

1999 ◽  
Vol 65 (12) ◽  
pp. 5541-5545 ◽  
Author(s):  
Dwayne A. Elias ◽  
Lee R. Krumholz ◽  
Ralph S. Tanner ◽  
Joseph M. Suflita
Keyword(s):  
Liquid Chromatography ◽  
Environmental Samples ◽  
High Performance ◽  
Methanogenic Bacteria ◽  
Most Probable Number ◽  
Environmental Matrices ◽  
Coenzyme M ◽  
Simple Method ◽  
Probable Number ◽  
Pure Cultures

ABSTRACT Determination of the role of methanogenic bacteria in an anaerobic ecosystem often requires quantitation of the organisms. Because of the extreme oxygen sensitivity of these organisms and the inherent limitations of cultural techniques, an accurate biomass value is very difficult to obtain. We standardized a simple method for estimating methanogen biomass in a variety of environmental matrices. In this procedure we used the thiol biomarker coenzyme M (CoM) (2-mercaptoethanesulfonic acid), which is known to be present in all methanogenic bacteria. A high-performance liquid chromatography-based method for detecting thiols in pore water (A. Vairavamurthy and M. Mopper, Anal. Chim. Acta 78:363–370, 1990) was modified in order to quantify CoM in pure cultures, sediments, and sewage water samples. The identity of the CoM derivative was verified by using liquid chromatography-mass spectroscopy. The assay was linear for CoM amounts ranging from 2 to 2,000 pmol, and the detection limit was 2 pmol of CoM/ml of sample. CoM was not adsorbed to sediments. The methanogens tested contained an average of 19.5 nmol of CoM/mg of protein and 0.39 ± 0.07 fmol of CoM/cell. Environmental samples contained an average of 0.41 ± 0.17 fmol/cell based on most-probable-number estimates. CoM was extracted by using 1% tri-(N)-butylphosphine in isopropanol. More than 90% of the CoM was recovered from pure cultures and environmental samples. We observed no interference from sediments in the CoM recovery process, and the method could be completed aerobically within 3 h. Freezing sediment samples resulted in 46 to 83% decreases in the amounts of detectable CoM, whereas freezing had no effect on the amounts of CoM determined in pure cultures. The method described here provides a quick and relatively simple way to estimate methanogenic biomass.

Listeria monocytogenes Contamination of Turkey Franks: Evaluation of a Production Facility

1990 ◽  
Vol 53 (12) ◽  
pp. 1015-1019 ◽  
Author(s):  
JAY D. WENGER ◽  
BALA SWAMINATHAN ◽  
PEGGY S. HAYES ◽  
STANLEY S. GREEN ◽  
MARK PRATT ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Food Processing ◽  
Environmental Samples ◽  
Meat Products ◽  
Conveyor Belt ◽  
Most Probable Number ◽  
Retail Outlet ◽  
Probable Number ◽  
Processing Plants ◽  
Production Stages

A facility which produced turkey franks that had been microbiologically linked to a case of human listeriosis was evaluated to establish prevalence of contamination and identify potential points for intervention. Listeria monocytogenes was isolated from only two of 41 environmental samples obtained in the plant. Among production line product samples analyzed by the Centers for Disease Control, 0 to 8% of samples from the production stages before the peeler-conveyor belt apparatus were positive for the case strain of L. monocytogenes, whereas 12 of 14 (86%) samples collected from this apparatus were positive (p <0.001). The most probable number (MPN) of L. monocytogenes in finished product purchased from a retail outlet was less than 0.3 per gram; however, the opened package of franks from the case patient's refrigerator had an MPN of >1100 per gram. These data suggest that systematic culturing and analysis of products and production facilities may help identify appropriate interventions to reduce L. monocytogenes contamination in food processing plants and contribute to control of L. monocytogenes in ready-to-eat meat products.

Twenty-Four-Hour Direct Presumptive Enumeration of Listeria monocytogenes in Food and Environmental Samples Using the ISO-GRID Method with LM-137 Agar

2000 ◽  
Vol 63 (3) ◽  
pp. 354-363 ◽  
Author(s):  
PHYLLIS ENTIS ◽  
IRINA LERNER
Keyword(s):  
Listeria Monocytogenes ◽  
Environmental Samples ◽  
Membrane Filter ◽  
Grid Method ◽  
Raw Milk ◽  
Most Probable Number ◽  
Filter Method ◽  
Fermented Sausage ◽  
Probable Number ◽  
The U.S

A new culture medium, LM-137 agar, was developed for use with the ISO-GRID hydrophobic grid membrane filter system for direct presumptive enumeration of Listeria monocytogenes in 24 h. The method was validated against three-replicate, three-dilution most probable number procedures based on enrichment methods specified by the U.S. Department of Agriculture, the Association of Official Analytical Chemists International and the U.S. Food and Drug Administration. The study encompassed meats, dairy products, egg, produce, seafood, and environmental samples. The ISO-GRID filter method produced significantly higher recovery of L. monocytogenes from fermented sausage, hot dogs, pasteurized and raw milk, raw shrimp, and environmental swab samples (P < 0.05). The reference methods yielded significantly higher counts from frozen raw pork and cole slaw (P < 0.05). Confirmation rates of presumptive positive isolates from the filter method ranged from a low of 92% (frozen raw pork) to 100% (most other products). Neither the recovery efficiency nor the confirmation rate were affected by the presence of competing aerobic flora.

Modified most-probable-number technique for the specific determination of Escherichia coli from environmental samples using a fluorogenic method

1990 ◽  
Vol 12 (3-4) ◽  
pp. 235-245 ◽  
Author(s):  
Ma Carmen Balebona ◽  
Miguel A. Moriñigo ◽  
Roberto Cornax ◽  
Juan J. Borrego ◽  
Valeria M. Torregrossa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Environmental Samples ◽  
Most Probable Number ◽  
Probable Number ◽  
Specific Determination

Analysis of Coliform and Colifecal Total Pollution Test on Various Types of Drinking Water Using the MPN (Most Probable Number) Method

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Wanda Aulya ◽  
Fadhliani Fadhliani ◽  
Vivi Mardina
Keyword(s):  
Drinking Water ◽  
Fecal Coliform ◽  
Pathogenic Bacteria ◽  
Microbiological Quality ◽  
Coliform Bacteria ◽  
Most Probable Number ◽  
Inspection Method ◽  
Sample Number ◽  
Probable Number ◽  
Fecal Coliform Bacteria

Water is the main source for life and also the most severe substance caused by pollution. The mandatory parameters for determining microbiological quality of drinking water are total non-fecal Coliform bacteria and Coliform fecal (Escherichia coli). Coliform bacteria are a group of microorganisms commonly used as indicators, where these bacteria can be a signal to determine whether a water source has been contaminated by bacteria or not, while fecal Coliform bacteria are indicator bacteria polluting pathogenic bacteria originating from human feces and warm-blooded animals (mammals) . The water inspection method in this study uses the MPN (Most Probable Number) method which consists of 3 tests, namely, the presumption test, the affirmation test, and the reinforcement test. The results showed that of 15 drinking water samples 8 samples were tested positive for Coliform bacteria with the highest total bacterial value of sample number 1, 15 (210/100 ml), while 7 other samples were negative. From 8 positive Coliform samples only 1 sample was stated to be negative fecal Coliform bacteria and 7 other samples were positive for Coliform fecal bacteria with the highest total bacterial value of sample number 1 (210/100 ml).

Cemaran Eshericia coli dalam makanan laut yang beredar di pasar tradisional Kota Pontian

2015 ◽  
Vol 1 (1) ◽  
pp. 44
Author(s):  
Rafika Sari ◽  
Pratiwi Apridamayanti
Keyword(s):  
Most Probable Number ◽  
Probable Number

Latar Belakang: Makanan laut merupakan salah satu jenis makanan yang banyak dikonsumsi oleh masyarakat selain sebagai komoditi ekspor. Mengkonsumsi makanan laut yang telah terkontaminasi bakteri hidup atau toksin yang dihasilkannya dapat menyebabkan keracunan makanan. Tujuan penelitian ini adalah untuk mengetahui adanya kontaminasi bakteri koliform E.coli sebagai indikator pencemaran pada makanan laut dan memberikan informasi kelayakan dan keamanan konsumsi dari makanan laut di dua pasar tradisional terbesar di daerah Pontianak. Metode: Sampel yang digunakan adalah ikan, sotong dan udang. Penelitian terhadap sampel dilakukan menggunakan uji Most Probable Number (MPN) yang dilengkapi dengan uji biokimia untuk mengidentifikasi jenis bakteri pada sampel melalui penanaman bakteri pada media agar Lactose Broth (LB) dan Briliant Green Lactose Bile Broth (BGLB). Hasil: Hasil penelitian menunjukkan bakteri koliform E.coli terdeteksi pada 100% sampel dengan nilai MPN yang tidak memenuhi kriteria kelayakan konsumsi, yakni >3/g. Kesimpulan: Makanan yang ada tidak memenuhi kriteria kelayakan konsumsi.

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