What is an advantage of a direct plate count? Advantages of Direct Microscopic Count
Rapid, Simple and easy method requiring minimum equipment. Morphology of the bacteria can be observed as they counted. Very dense suspensions can be counted if they are diluted appropriately.
What is the advantage of the plate count method? Despite its shortcomings, the viable plate count is a popular method for determining cell number. The technique is sensitive and has the advantage of only counting living bacteria, which is often the important issue. Any concentration of microorganism can be easily counted, if the appropriate dilution is plated.
What is direct plate count? Counting Colonies: An example of counting colonies on a streak plate. Direct counting methods include microscopic counts using a hemocytometer or a counting chamber. The colonies can then be counted and, based on the known volume of the culture that was spread on the plate, the cell concentration can be calculated.
What is one of the advantages of using direct microscopic counts DMC? Advantage of Direct Microscopic Count
Rapid, Simple and easy method. Require less time to perform. A large number of samples can be screened in a given period of time. Useful in providing the estimated counts, types of bacteria and somatic cells in milk.
What is an advantage of a direct plate count? – Related Questions
What are the disadvantages of plate count assays?
among these disadvantages are: (1) the length of time required for incubation, 48 hours being the shortest; (2) large amount of glassware and culture medium required, as well as other expensive equipment, and (3) the paucity of details regarding the kinds of organisms present.
How is the standard plate count is performed?
The standard plate count method consists of diluting a sample with sterile saline or phosphate buffer diluent until the bacteria are dilute enough to count accurately. That is, the final plates in the series should have between 30 and 300 colonies.
Is total plate count the same as aerobic plate count?
The APC term stands for aerobic plate count, but again is interchangeable with the others. Other terms used more historically are Standard Plate Count, Mesophilic Count or Total Plate Count these too generally refer to aerobic bacteria able to grow at average temperatures (e.g. 30 to 40°C).
Is plate count a direct or indirect?
Indirect viable cell counts, also called plate counts, involve plating out (spreading) a sample of a culture on a nutrient agar surface.
What are 3 methods used to identify bacteria?
Traits that can be valuable aids to identification are combinations of cell shape and size, gram stain reaction, acid-fast reaction, and special structures including endospores, granules, and capsules.
What is meant by plate count?
The standard plate count, sometimes also referred to as the total plate count, is probably the most widely used technique for evaluating microorganisms in foods. The purpose, as its name implies, is to estimate the number of viable microorganism cells in a given sample of food.
What are the advantages and disadvantages of direct microscopic count?
Although rapid, a direct count has the disadvantages that both living and dead cells are counted. Only dense suspensions can be counted (>107 cells per ml), but samples can be concentrated by centrifugation or filtration to increase sensitivity. It is not sensitive to populations of fewer than 1 million cells.
What pH do most bacteria grow best in?
Most bacteria grow best around neutral pH values (6.5 – 7.0), but some thrive in very acid conditions and some can even tolerate a pH as low as 1.0. Such acid loving microbes are called acidophiles. Even though they can live in very acid environments, their internal pH is much closer to neutral values.
What are the disadvantages of DMC?
The major drawbacks of the direct synthesis of DMC are the low yield and reaction rate, mostly induced by the highly stable carbon dioxide molecules.
What does CFU stand for?
A colony forming unit, or CFU, is a unit commonly used to estimate the concentration of microorganisms in a test sample.
What will be the plate count of good quality water?
Heterotrophic plate count levels in potable water should be 500 CFU/mL would indicate a general decrease in water quality. A direct correlation between heterotrophic plate count and biofilm levels has been demonstrated.
What is the difference between total plate count and total viable count?
The main difference between the two is that total count determines the count of all cells both dead and alive while viable count estimate the number of viable or live cells only capable of growing into distinct colonies.
What is standard plate count in water?
It should be emphasized that a standard plate count of 500/ml is attainable by water systems.
What is the range for a countable plate?
The countable plate has between 30 and 300 colonies. More than 300 colonies would be difficult to count, and less than 30 colonies is too small a sample size to present an accurate representation of the original sample.
What is total bacterial count?
The total bacteria count (TBC) of a substance is a quantitative estimate of the number of microorganisms present in a sample. This measurement is represented by the number of colony-forming bacterial units (CFU) per gram (or milliliter) in the sample. Total bacteria count is also known as the total viable count (TVC).
How do I reduce my aerobic plate count?
Exposure of eggshells to 30 and 60 s UV significantly reduced aerobic plate counts compared to untreated eggs. Exposure to 60 s of UV resulted in a 2 to 3 log10 cfu/egg APC reduction and reduced counts below detectable levels.
What is a safe aerobic plate count?
Dilution factors may exaggerate low counts (less than 25), and crowded plates (greater than 250) may be difficult to count or may inhibit the growth of some bacteria, resulting in a low count. Report counts less than 25 or more than 250 colonies as estimated aerobic plate counts (EAPC).
What is the difference between direct and indirect counts?
The direct methods involve counting cells, whereas the indirect methods depend on the measurement of cell presence or activity without actually counting individual cells.
Is direct microscopic count accurate?
The direct microscopic count of individual cells per cubic centimeter varied from 4.8 to 6.2 times greater than the count of the groups of bacteria under the microscope, and from 3 to 4.5 times greater than the agar plate colony count.
How do we identify bacteria?
Bacteria are identified routinely by morphological and biochemical tests, supplemented as needed by specialized tests such as serotyping and antibiotic inhibition patterns. Newer molecular techniques permit species to be identified by their genetic sequences, sometimes directly from the clinical specimen.
What is CFU per ml?
cfu stands for colony-forming unit. This means that cfu/g is colony-forming unit per gram and cfu/ml is colony-forming unit per millilitre. They give you the results of the number of colony-forming units, for the number of grams or millilitres of test material that they put on the petri dish.