Spread plate technique principle, procedure and uses. Pour plate technique procedure, advantages, limitations. Inoculum refers to microorganisms, bacteria or fungi that grow in or on the nutrient agar. Two different types of agar plate isolation techniques will be usedstreak and pour. Spread plate technique methods of isolating pure culture 3. However, colony morphology is not a reliable way to identify bacteria, as many different types of bacteria have similar colony morphology. A comparison of pour plate and spread plate methods. Some individual bacterial cells are separated and well spaced from each other. What advantage does the streakplate method have over the. Streak plate technique for isolation of microorganism. Advantages and disadvantages of the serial dilution agar. What are the disadvantages of the streak plate method. Successful streaks lead to individual colonies of microbes.
Oct 03, 2009 at the end of incubation there should be enough bacteria to form visible colonies in the areas touched by the inoculation loop. Thats certainly one way of quantifying the population. While all molecular biologists know or have at least seen a spread plate aka petri dish with some agar in it, a pour plate is quite exotic. Back in the lab, you put a sample on a slide under a microscope, and counted everything that looked like a. In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. What is a disadvantage of the streak plate technique. Jun 04, 2018 the main difference between pour plate and spread plate is that the molten agar is poured on to the inoculum during the preparation of the pour plate whereas inoculum is spread on the surface of the solidified agar during the preparation of the spread plate. Explain advantages and disadvantages of spread plate method.
Principles of differential, enriched and selective media, and various biochemical tests 3. Streak plate technique is used for the isolation into a pure culture of the. Antonio it is refreshing to see such wisdom knowing that there are at least two methods of pouring plates in a young man. Streak plate technique is used for the isolation into pure culture of the organisms mostly bacteria, from mixed population. Preparation for pour plate method is time consuming compared with streak plate and or spread plate technique.
Microbiologists rely on aseptic technique, dilution, colony streaking and spread plates for daytoday experiments. Agar plates were incubated at 37 c for 24 h before counting, and then photographed. Comparison of the pour, spread, and drop plate methods for. In streak plate culture method, a sterilized loop or transfer needle is dipped into the mixed culture of the specimen. Advantages and disadvantages of streak, spread and pour. It helps to reduce a dense culture of cells to a more usable concentration. Dear all, im just wondering which method you guys are applying in your companies. Apr 02, 2011 the advantage of the spread plate over the pour plate is duh. Comparison pour, spread, plate methods enumeration of. Principle, procedure, applications, advantages, limitations of spread plate technique.
The streak plate method is a rapid qualitative isolation method. The pour plate method of counting bacteria is more precise than the streak plate. Streak plating is a method that allows microorganisms to be grown from a sample on an agar plate. Aseptic technique is basically the mindset of keeping things free of contamination, as the world we live in has so many microbes that can interfere with experiments. Dear aunt yersinia, what are advantages and disadvantages of pour and spread plates. The spread plate technique involves using a sterilized spreader with a smooth surface made of metal or glass to apply a small amount of bacteria. Streak plate method principle, methods, significance, limitations. Isolation of bacterial colonies using the quadrant method the streak plate procedure is designed to isolate pure cultures of bacteria, or colonies, from mixed populations. The streak plate method enables you to select and work with individual colonies. The number of viable microorganisms in a sample can be counted by using the pour plate method or the spread plate method. The streak plate culture technique for the isolation of microorganism is the most practical method of obtaining discrete and welldeveloped colonies of the microbe in pure cultures.
Most microbiologists repeat streaking from an isolated colony two to three times before they guarantee culture purity. Jul 09, 2014 what are advantages and disadvantages of pour and spread plates. Disadvantages fungi cannot be identified to species with this method. Principle, procedure, uses, and dis advantagesoctober 16. Advantages and disadvantages method advantages disadvantages. The colony becomes visible to the naked eye and the number of colonies on a plate can be counted. If the streaking technique is not done properly or if there is too much of an organism present on the inoculating. What are two advantages of the streak plate technique. It is the ideal method if you are doing general work with a certain type of microorganism. From these mixed colonies, single bacterial or fungal species can be identified based on their morphological sizeshapecolour differences, and. Streak plating is a microbiology laboratory method that has two major disadvantages.
Due to the similarities in spore morphology, some spores will be grouped together, i. The pour plate method of counting bacteria is more precise than the streak plate method, but, on the average, it will give a lower count. The serial dilution method is utilized to decline the number of microorganism in the inoculum. Interpretation method of microbial identification test things to do. The spread plate technique involves using a sterilized spreader with a smooth surface made of metal or glass to.
Know other methods described in the manual, text or class to achieve isolation besides the streak plate method and their advantages and disadvantages when compared to the streak plate method. Other disadvantages are the reduced growth rate of. A comparison was made of agar plates spread with glass rods and poured agar plates for the enumeration of bacteria in the waters of fishers island sound, salinity 30. Colonies that differ in appearance are typically different bacterial strains, species, or genera. The techniques commonly used for isolation of discrete colonies initially require that the number of organisms in the inoculums be reduced. Spread plate technique is the method of isolation and enumeration of microorganisms in a mixed culture and distributing it evenly. Bacteria are dragged from the top section to one of the bottom sections, then from that bottom section to the other. Streak plate 11 pour plate 12 using a spreader spread plate 14. If you continue browsing the site, you agree to the use of cookies on this website. Thepourplate methodofcountingbacteria is moreprecise than the streak plate method, but, onthe average, it will give alower count. By streak plate method one can isolate a bacterial strain, from a mixed culture, in pure form as colony. Difference between pour plate and spread plate pediaa.
The inoculum is streaked over the agar surface in such a way that it thins out the bacteria. Isolation of bacteria by dilution techniques flashcards. The plate count method or spread plate relies on bacteria growing a colony on a nutrient medium. The drop plate method was preferred because of its economy in materials and labor. Overview of pour plate method and spread plate method. The spread plate as a method for the enumeration of marine bacteria john d. Ofthe three methods, the drop plate procedure was the most preferable because more countscouldbemadeononeplate fig. It can used only for obtaining isolated colonies in pure culture. Preparation for the pour plate method is time consuming compared with streak plateand or spread plate technique. Isolate single bacterial colonies by the streakplating method.
Streak plate method principle, methods, significance. Streak plate technique streaking is the process of spreading the microbial culture with an inoculating needle on the surface of the media. The vaselinesealed depression also slows down the dryingout process, so the organisms can be observed for longer periods. Home basic microbiology streak plate method principle, methods, significance, limitations.
In this technique, a serially diluted specimen containing 2 or more bacteria or microbe mixed culture is used which is spread over the solidified agar media plates as a thin layer with the help of a sterile lshape glass rod spreader while the media plate is spun on a turntable. This allows for individual colonies to be isolated from other colonies. Each method has advantages and disadvantages, and particular uses. The spread plate seems to be your method of choice when compared with the mpn for any application with the following exceptions.
Firstly, users will not be able to grow obligate anaerobes using this method. Streak plate method advantages and disadvantages advantages. Prior to sampling, calibrate your pump to 15 liters per minute via a rotameter. What is the difference between streak plate and pour plate. One advantage of using beads instead of a spreader is that no open containers. Streak plate method cannot be used for the enumeration of the approximate number of bacteria in the given sample. The pour plate method of counting bacteria is more precise than the streak plate method, but, on the average, it will. The following methods are used to isolate pure culture. Ptak and ginsburg12 also listed these advantages for the streak plate method and showed that for the same samples. Embedded colonies are much smaller than those which happen to be on the surface.
May 08, 2019 what are the disadvantages using streak plate method. A disadvantage of the streak plate technique could be colony isolation problems. What are the disadvantages using streak plate method. Learn vocabulary, terms, and more with flashcards, games, and other study tools. Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested.
Aug 15, 2019 spread plate technique is the method of isolation and enumeration of microorganisms in a mixed culture and distributing it evenly. The dilution or isolation by streaking method was first developed by loeffler and gaffky in kochs laboratory, which. To pour or to spread, this is the question bitesize bio. A comparison was made of agar plates spread with glass rods and poured agar plates for the enumeration of bacteria in the waters of fishers island. Micro students may find this presentation on culture methods useful slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Principle the streak plate technique is essentially a method to dilute the number of organisms, decreasing the density. Colony streaking leads to to the isolation of individual. To report and interpret observation of identification tests tests have been. Full text get a printable copy pdf file of the complete article 364k, or click on a page image below to browse page by page. What are the disadvantages using streak plate method answers. The technique makes it easier to quantify bacteria in a solution. Advantages and disadvantages of serial dilution method ask for details. I am a qa analyst in a biscuit company and have been having a hard time deciding which method to use to verify the microbiological level of our finished products.
Furthermore, the volume of inoculum in the streak plate is only a. Generally the dilution factor at each step is constant. Loop is flamed to kill any potentially contaminating bacteria. Method of isolation of pure culture linkedin slideshare. Bacterial colony morphology and identification of bacteria. Of these the surface spread plate method is now widely used in europe and is. Loop is flamed to kill any potentially contaminating bacteria before inoculation. The serial dilution method involves a stepwise dilution of a. Advantages and disadvantages of serial dilution method. The term colony morphology refers to the visible characteristics of a colony. The main difference between pour plate and spread plate is that the molten agar is poured on to the inoculum during the preparation of the pour plate whereas inoculum is spread on the surface of the solidified agar during the preparation of the spread plate. By using a differential medium one can also make a presumptive identification of. A loop is used to streak the mixed sample many times over the surface of a solid culture medium in a petri plate. Streak plate methods vary by the number of agar sections streaked.
Full text get a printable copy pdf file of the complete article 209k, or click on a page image below to browse page by page. So what advantages are there for one method over the other. It is essentially a dilution technique that involves spreading a loopful of culture over the surface of an agar plate. Spread plate technique principle, procedure, advantages. Get a printable copy pdf file of the complete article 209k, or click on a. Basic practical microbiology a manual by society for general microbiology sgm. Disadvantage of the streak plate technique answers. What is the advantage of viable count method over the. In the pour plate technique, diluent containing the sample typically 1 ml is added to a sterile petri dish. Two dilutions 106 and 10 of the peat inoculant were plated in quadruplicate and incubated at 28c for 7 days. To be effective, the dilution of the original sample must be arranged so that on average between 30 and 300 colonies of the target bacterium are grown.
Like the wet mount, the hanging drop method preserves cell shape and arrangement. Jan 14, 2020 streak plate method advantages and disadvantages advantages. What is the advantages of streak plate method answers. The hanging drop method is also far too risky to use with highly pathogenic organisms. Cleverdon department of bacteriology, university of connecticut, storrs, connecticut abstract a comparison was made of agar plates spread with glass rods and poured agar plates for the enumeration of bacteria in the waters of fishers island. Loss of viability of heatsensitive organisms coming into contact with hot agar. Nov 25, 2017 the following methods are used to isolate pure culture.
Streak plate, spread plate and pour plate what is the steak plate technique for isolation. Secondly, only organisms that were viable in the original sample are able to be grown. The main difference between streak plate and pour plate is that in streak plate, the first to be added is the melted nutrient agar and the second to be added is a loop of bacteria from a slant, whereas the first to be added in pour plate is the bacterial broth and the second to be added is the nutrient agar. Isolation of bacteria by dilution techniques flashcards quizlet. When you have a streak plate, your endgoal is to isolate individual colonies of your microbe.
Samples can then be taken from the resulting colonies and a microbiological culture can be grown on a new plate so that the organism can be identified, studied, or tested the modern streak plate method has progressed from the efforts of robert. This method is used for isolating the discrete colonies of the microorganism. At the end of incubation there should be enough bacteria to form visible colonies in the areas touched by the inoculation loop. The streak plate isolation method as described on the steps mentioned above. Hasslefree, convenient, usually you will be able to get a few visible individual colonies in just one plate if your streaking skills are good. The spread plate is designed to create a lawn of the microbe evenly across the plate. Aseptic technique, dilution, streaking, and spread. The initial inoculum is placed in the top half of the plate. Streak plate method is utilized for the qualitative isolation of the microorganism. Streak plate method of isolation purpose the streak plate technique is the most widely used method of obtaining isolated colonies from a mix of cultures.
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