Total colony count

These bacteria were cultivated in each product for 24 h at 37 °C and each cultured broth sample was serially diluted into the corresponding aseptic products. The total colony count was determined with Plate Count Agar (MERCK). Bioluminescent Assay... 

In addition, eertain eompendial requirements for content and delivered dose uniformity should be measured. The USP and EP propose that the total aerobic count not exceed 100 CFU/g (colony-forming imits) that the total yeast and mold counts not exceed 10 CFU/g and that no specific pathogens be detectable. Specifications for the other attributes should be based on the intended use and the historical performance of the product. As with other dosage forms, specifications must be met throughout the intended shelf life of the product. 

Total viable counts (TVCs) were immediately carried out on duplicate controls with no biocide added. The slurries were incubated at 37 °C for 4 hours and TVCs were performed at that time point and at several points over the following 6 weeks. Re-inoculations were carried out after 3 weeks. The resulting bacterial numbers were recorded as colony forming units (cfu)/ml of slurry. 

A cooling tower with a total plate count (TAB) of less than 5 x 104 colony-forming units per milliliter (cfu/ml) water is generally considered to be under adequate control. In the United Kingdom, a level of 1 x 104 cfu/ml tends to be the acceptable maximum for hospital and health care premises (although at 1 x 103 104 cfu/ml a program review may be necessary). 

The most frequently used dip-slide is the total aerobic bacteria/total bacteria count (TAB/TBC). The method employed is to unscrew the cap, remove the dip-slide by the cap, and immerse it into the cooling water sample for 2 to 3 seconds so that both media surfaces are fully covered by liquid. Any excess liquid should be quickly drained and the cap screwed back on the bottle. The bottle should be stored upright for 24 to 36 hours at 25 to 30° C. Then the (usually colored) bacterial colonies should be compared with a chart for conversion to a (reasonably) quantitative interpretation of the results. Typically, the cooling water results will indicate a TAB of between 1 x 103 and 1 x 107 cfu/ml. 

Use the dilution factors and colony counts to determine the total number of viable cells (Trp+ plus Trp-) present per milliliter of undiluted culture in tubes 1 and 2. Assuming that all of the Trp+ cells are transformants and assuming that the total number of viable cells in tubes 2 through 6 is the same, calculate the efficiency of transformation in tubes 2 to 6. Interpret all your results in terms of the contents of each tube and your knowledge of the process of transformation. Which tubes served as controls for the experiment Explain. 

In order to characterize water quality, the following parameters were measured from the water samples in accordance with Hungarian Standards total organic carbon (TOC), chemical oxygen demand, concentrations of ammonium, nitrite and nitrate ion, iron, manganese, pH, conductivity, m-alkality, turbidity, and heterotroph colony count. 

The total viable count is an important parameter in industrial fermentations. Traditional methods for total viable count started with the cultivation method of counting the colonies. Later methylene blue and Ponceau S stain came into use for microscopic examinations, which give a direct count (Kunkee Neradt, 1974). Today, systems are available with smart filtering and concentration steps and sensitive fluorescence stains, and a result can be obtained in less than lOmin. This method cannot be applied to highly viscous or particulate materials. 

Culture This technique is easy to perform and does not require expensive equipment. It is used to determine the number of colony-forming units (CFU) in a water sample using part 9000 of the Standard MethodsS. The number of CFU in a sample is an expression of the number of culturable microorganisms present. Note that while this technique is relatively inexpensive, the counted colonies may represent only about 1 - 10% of the total bacterial count (TBC). Never-the-less, this technique can be useful... 

Total colony-forming units (CFU)/ml of aerobic bacteria were carried out in tryptic soy agar (TSA) (DIFCO Laboratories) by standard plate count procedures. 

Count the colonies on the dilution plates the next day to determine the total number of transformants. Harvest the library cells by flooding each of the 36 plates with 4mL SOC medium and detach cells by scraping off under sterile conditions. Pool the cell suspension and add DMSO to a final concentration of 9% (v/v). Store at —70°C in, e.g., 2-mL aliquots or use directly in library screening. 

Total count for aerobic bacteria averages 150 x 10,000. It is presumed that these units are colony-forming units per milliliter(cfu/ml). 

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