A miniaturized counting technique for anaerobic bacteria

1976 ◽  
Vol 22 (12) ◽  
pp. 1728-1733 ◽  
Author(s):  
A. N. Sharpe ◽  
G. L. Pettipher ◽  
G. R. Lloyd

A miniaturized counting technique gave results as good as the pour-plate and Most Probable Number (MPN) techniques for enumeration of Clostridia spp. and anaerobic isolates from the gut. Highest counts were obtained when ascorbic acid (1%) and dithiothreitol (0.015%) were added to the reinforced clostridial medium used for counting. This minimized the effect of exposure to air before incubation. The miniature technique allowed up to 40 samples to be plated and incubated in one McIntosh-Filde's-type anaerobic jar, compared with 3 or 4 by the normal pour plate.

1997 ◽  
Vol 60 (12) ◽  
pp. 1574-1576 ◽  
Author(s):  
O. A. OGUNRINOLA ◽  
C. G. EDWARDS ◽  
P. M. DAVIDSON

Untreated ‘Alaska’ seed peas have traditionally been used to prepare PE-2 medium, a medium used to recover anaerobic bacteria. Three cultivars of seed peas, ‘Columbian’, ‘Yellow’, and ‘Scotch’ were compared to the cultivar ‘Alaska’ peas in PE-2 for recovery of Clostridium butyricum ATCC 860, Clostridium sporogenes ATCC 7955/NCA 3679, and Thermoanerobacterium thermosaccharolyticum ATCC 25773 determined by using the most probable number (MPN) technique. Organisms were grown in cooked meat medium (CMM) and enumerated by the three-tube MPN method in PE-2 media incubated at 37°C for 48 h. Recovery of C. butyricum and T. thermosaccharolyticum grown in homogenates of commercial cream-style corn and vegetable beef soup were also evaluated. Similar recovery of organisms from stock cultures or from foodstuffs were observed in PE-2 prepared with three of the pea cultivars (‘Alaska’, ‘Columbian’, and ‘Yellow’). While the ‘Scotch’ cultivar PE-2 medium yielded recoveries comparable to PE-2 prepared with the other pea cultivars, turbid tubes were occasionally observed from which viable microorganisms could not be recovered. This cultivar is therefore not recommended due to the probability of yielding false positives in the MPN technique.


Dairy ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 500-514
Author(s):  
Fabio Abeni ◽  
Rosanna Marino ◽  
Francesca Petrera ◽  
Giulia Segati ◽  
Andrea Galli ◽  
...  

At feed-out, aerobic spoilage of silage enables an increase in anaerobic spore-forming bacteria (ANSB) that may enter the total mixed ration (TMR). The aim of our study was to understand whether in hot summers the silage structures and management may affect the level of ANSB in milk for long-ripening cheese production. A survey of silage facilities, management, and their relationships with silage, TMR, feces, and milk ANSB most probable number (MPN) content was conducted in the Po Valley during summer months. Silo type did not affect the mean ANSB, but only the wideness of their value distributions, with a narrow range for bags and a wider range for bunkers. The unloading equipment affected the ANSB count; the front-end loader with cutter was associated with a lower ANSB count—probably as a result of the reduced surface left after daily silage removal. Silo length and daily removed face width were the main factors affecting contamination of silage by spore-forming bacteria during summer, with longer silos and wider surface removal reducing ANSB contamination—probably as a consequence of reduced aerobic spoilage at the silage surface. The silage contamination by spore-forming bacteria within a log10 2 MPN g−1 allowed a low concentration of spore-forming bacteria at the farm bulk milk tank level. Fecal ANSB levels did not factor into the regression that explains the ANSB in farm milk. It has been found that silage facilities’ features and their management are an important first step to reduce the extent of ANSB contamination at the farm level.


2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Wahyu Wilopo ◽  
Keiko Sasaki ◽  
Tsuyoshi Hirajim

Permeable reactive barrier column tests were performed to investigate whether anaerobic bacteria in sheep manure could help remove As from groundwater. One column served as a control and was packed with zero-valent iron (ZVI), compost leaf, wood chips, glass beads, and gravel, after which it was sterilized. The other (‘inoculated column’) was packed with the same ingredients, with the addition of sheep manure as a source of anaerobic bacteria. Simulated As-contaminated groundwater was prepared based on groundwater samples from Sumbawa Island, Indonesia, but with the arsenic concentration adjusted to 50 mg/L. The inoculated column was found to remove As more effectively from the simulated groundwater than the sterilized one. A gradual decrease in sulfate concentration was observed in the inoculated column at the rate of 0.26 mmol of sulfate/L/day, suggesting that there was sulfate-reducing activity in the microbial population. In addition, the sulfur isotope ratio showed -4.3 (‰) and 0.2 (‰) in influent and effluent, respectively, indicating that sulfate-reducing bacteria (SRB) consumed δ32S preferentially. Using population size estimates from the most probable number (MPN) method, the population of SRB was found to increase with distance traveled in the column. Profiling the community composition of the bacteria in different fractions of the inoculated column using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) on 16S rRNA sequences suggested that a majority of bacteria were various Clostridium species and one species of Proteobacteria, Geobacter metallireducens GS-15. Some of them may contribute to the removal of arsenic.Keywords: Sheep manure, zero valence iron, arsenic, immobilization, sulfate-reducing bacteria


2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Wanda Aulya ◽  
Fadhliani Fadhliani ◽  
Vivi Mardina

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).


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

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.


1991 ◽  
Vol 24 (2) ◽  
pp. 149-152 ◽  
Author(s):  
N. A. Grabow ◽  
E. J. Pienaar ◽  
R. Kfir

A total of 510 service water samples from cooling towers throughout South Africa were analysed for the presence of Legionella bacteria. Legionella was detected using an immuno-labelling technique based on the most probable number principle. Only cultural (viable) bacteria were counted. Legionellae were found in most of the samples tested. However, in only 4% of the samples a high level of legionellae was recorded. No correlation was found between the numbers of legionellae and those of standard plate counts. Biocide treatment was shown to be effective in the removal of the bacteria from cooling towers after a 3-month treatment period.


1991 ◽  
Vol 24 (2) ◽  
pp. 143-147 ◽  
Author(s):  
N. A. Grabow ◽  
R. Kfir ◽  
W. O. K. Grabow

A new quantitative method for the enumeration of Legionella bacteria in water is described. Appropriate tenfold serial dilutions of water samples concentrated by membrane filtration are plated in triplicate on buffered charcoal yeast extract agar. After incubation for 3 days representative smears from individual plates are tested for the presence of Legionella by direct fluorescent antibody staining. The number of positive plates in each dilution is used to calculate the Legionella count by means of conventional most probable number statistics. In comparative tests on a variety of water samples this method yielded significantly higher counts than previously used procedures.


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