Microbiology of food and animal feeding stuffs. Horizontal method for the determination of low numbers of presumptive Bacillus cereus. Most probable number technique and detection method

2006 ◽  
2007 ◽  
Vol 70 (12) ◽  
pp. 2774-2781 ◽  
Author(s):  
I-CHEN YANG ◽  
DANIEL YANG-CHIH SHIH ◽  
JAN-YI WANG ◽  
TZU-MING PAN

Members of the Bacillus cereus group may produce diarrheal enterotoxins and could be potential hazards if they enter the food chain. Therefore, a method capable of detecting all the species in the B. cereus group rather than B. cereus alone is important. We selected nhe as the target and developed a real-time PCR assay to quantify enterotoxigenic strains of the B. cereus group. The real-time PCR assay was evaluated with 60 B. cereus group strains and 28 others. The assay was also used to construct calibration curves for different food matrices and feces. The assay has an excellent quantification capacity, as proved by its linearity (R2 > 0.993), wide dynamic quantification range (102 to 107 CFU/g for cooked rice and chicken, 103 to 107 CFU/ml for milk, and 104 to 107 CFU/g for feces), and adequate relative accuracy (85.5 to 101.1%). For the low-level contaminations, a most-probable-number real-time PCR assay was developed that could detect as low as 100 CFU/ml. Both assays were tested with real food samples and shown to be considerably appropriate for B. cereus group detection and quantification.


2003 ◽  
Vol 41 (7) ◽  
pp. 2992-3000 ◽  
Author(s):  
T. K. Beattie ◽  
D. V. Seal ◽  
A. Tomlinson ◽  
A. K. McFadyen ◽  
A. M. Grimason

2019 ◽  
Vol 9 (2) ◽  
pp. 112
Author(s):  
SAWIDYA FITRIYANI ◽  
I WAYAN DANA ATMAJA ◽  
NI NENGAH SONIARI

Algae Genus in Organic Rice Fields Planted with Local and Inhibrida Rice in Subak Jatiluwih, Tabanan. The abundance of microalgae in rice fields, especially microalgae from Cyanophyta division that are capable of fixing nitrogen, is very important helping maintain soil fertility. The aim of this study was to find out the genus of algae in organic rice fields of Subak Jatiluwih, Tabanan. The research was conducted from September 2018 to April 2019. Sampling was done in Subak Jatiluwih. Algae breeding were carried out at Biology and Physics Laboratory, Faculty of Agriculture, Udayana University. This research method uses descriptive quantitative. The implementation of the research included the determination of location, soil and water sampling, identification of algae, and analysis of algae genera. Enrichment algae was carried out using the MPN method, results of the analysis of algae genus were found in 37 genera from 3 divisions i.e Chlorophyta, Cyanophyta and Chrysophyta. Descriptive quantitative method Most Probable Number (MPN) calculation conclude that there are not much different from the Local and Inhibrida rice fields. The maximum population algae of local rice fields is 1.100 cell g-1 and Inhibrida rice fields is >1.100 cell g-1 of land. The minimum population is 3,6 cell g-1 of land in local rice fields, and 9,2 cell g-1 of land in Inhibrida rice fields.


AGROFOR ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Veronika KUKUČKOVÁ ◽  
Nina MORAVČÍKOVÁ ◽  
Radovan KASARDA

The aim of this study was to assess genetic structure of Slovak Pinzgau populationbased on polymorphism at molecular markers using statistical methods. Femaleoffspring of 12 most frequently used bulls in Slovak Pinzgau breeding programmewere investigated. Pinzgau cattle were found to have a high level of diversity,supported by the number of alleles observed across loci (average 5.31, range 2-11)and by the high within-breed expected heterozygosity (average 0.66, range 0.64-0.73). The state of genetic diversity is satisfying and standard for local populations.Detection of 12 possible subpopulation structures provided us with detailedinformation of the genetic structure. The Bayesian approach was applied, detectingthree, as the most probable number of clusters. The similarity of eachsubpopulation using microsatellites was confirmed also by high-throughputmolecular data. The observed inbreeding (FROH=2.3%) was higher than thatexpected based on pedigree data (FPED=0.4%) due to the limited number ofavailable generations in pedigree data. One of the most important steps indevelopment of efficient autochthonous breed protection programs ischaracterization of genetic variability and assessment of the population structure.The chosen set of microsatellites confirmed the suitability in determination of thesubpopulations of Pinzgau cattle in Slovakia. The state of genetic diversity at moredetailed level was successfully performed using bovineSNP50 BeadChip.


2020 ◽  
Vol 42 ◽  
pp. e52965
Author(s):  
Wender Cardoso Silva ◽  
Ilva de Fátima Souza ◽  
Vivian Machado Benassi ◽  
Juan Pedro Bretas Roa ◽  
Paulo Henrique Graziotti ◽  
...  

The present work aimed to evaluate the degradability of the chitosan polymer by soil microorganisms. This evaluation was accomplished using the Most Probable Number (MPN) method by plating in drops so that soil microorganisms capable of degrading the polymeric material could be quantified. Soil samples diluted in three specific culture media for each type of microorganism were plated – bacteria, fungi and actinobacteria – and they were maintained at 28°C for seven days to determine the growth rate of fungi and actinobacteria, and for 48 hours for the development of bacteria. Significant differences in the MPN of actinobacteria relative to the other groups analyzed were observed. Thus, the method used was effective for determining the degradability of the chitosan biopolymer when observing the development of microorganisms subjected to the replacement of the carbon source by the addition of 2% w v-1 of the chitosan biopolymer to the culture medium. The formation of clear regions around the microbial colonies was a strong indicator of biodegradation.


1978 ◽  
Vol 24 (5) ◽  
pp. 552-557 ◽  
Author(s):  
A. L. Mills ◽  
C. Breuil ◽  
R. R. Colwell

Several media designed for use in a most probable number (MPN) determination of petroleum-degrading microorganisms were compared. The best results, i.e., largest numbers, were obtained using a buffered (32 mM PO4≡) liquid medium containing 1% hydrocarbon substrate. Of 104 presumptive oil degraders tested, 20 grew on oil agar medium but did not utilize oil or a mixture of pure paraffinic hydrocarbons (C10 to C16n-alkanes) in liquid (MPN) medium. Visible turbidity in the liquid medium was correlated with hydrocarbon utilization. Counts of petroleum degraders obtained using liquid medium (MPN) were in most cases higher than those obtained on an oil-amended silica gel medium. Both procedures yield an estimation of oil degraders, and the oil-amended agar permits growth of organisms which do not degrade crude oil. All strains of oil-degrading microorganisms examined in this study were lipolytic, but the converse was not always true.


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