The most common method for determining the total viable count is the pourplate method. The pour plate method of counting bacteria is more precise than the streak. Solid media tested for growth promotion is to be set up using pour plate method in order to determine a microbial plate count cfu which must be. The spread plate method uses a tool called a plate spreader or hockey stick. A perfect spread plate technique will results visible and isolated colonies of bacteria that are evenly distributed in the plate and are countable. May 11, 2012 conventional microbiology plating techniques such as the spread or pour plate method is used to measure bacterial growth 18. Comparison pour, spread, plate methods enumeration of. Moreover the single agar medium used, the conditions of incubation. These are the pour plate, membrane filtration, and multiple tube methods. Whether its customized environmental isolate controls, process controls, certified reference materials, proficiency samples, or something thats never been done before were up to the challenge. Use pour plating and spreadplating methods to determine the. Pour plate method is usually the method of choice for counting the number of. This method, as all other methods, has some limitations.
Fankhauser, phd 5 july 1989, rvsd 18 july 93, 21 july 95, 23 july 96, 21 july 97, 17 july 98, 28 jan 00, 28 june 02, 23july09, 22july10. Geldreich water samples collected during routine flushing of deadend mains were analyzed for bacterial count by using both pour plate and spread plate procedures. In the second technique, a measured volume of sample is passed through a fine filter that retains. Otherwise, with a dense population, only a quarter of the plate area is streaked. In the cup plate method, antibiotic containing cylinder is diffused into the agar layer containing the microorganisms. There are different types of methods for microbiological assay of antibiotics like cup plate method and disc diffusion method. Fankhauser, phd 5 july 1989, rvsd 18 july 93, 21 july 95, 23 july 96, 21 july 97.
The spread plate procedure may be employed over the pour plate technique for an enumeration experiment if the end goal is to isolate colonies for further analysis because colonies grow accessibly on the agar surface whereas they become embedded in the agar with the pour plate procedure. Simply add the bacteria to melted agar which is not so hot it. Simply add the bacteria to melted agar which is not so hot it will kill the desired bacterium. Pdf water samples collected during routine flushing of deadend mains were analyzed for.
Difference between pour plate and spread plate pediaa. How to make a pour plate laboratory technique youtube. Microbiology of food and animal feed realtime polymerase chain reaction pcrbased method for the detection of foodborne pathogens horizontal method for the detection of shiga toxinproducing escherichia coli stec and the determination of o157, o111, o26, o103 and o145 serogroups. The spread plate method is a technique to plate a liquid sample containing bacteria so that the bacteria are easy to count and isolate. In this case, an aliquot of the specimen to be cultured is placed in the bottom of an empty, sterile petri dish, then melted, cooled agar is poured over it. Aerobic mesophilic plate count total plate count 1 2. This manual, which explains the basic techniques necessary to carry out microbiology experiments safely and effectively, is intended as a guide for teachers and technicians. In the pour plate method a diluted bacterial sample is mixed with melted agar and then that mixture is poured into a petri dish. Pour plate method is neither as accurate nor as precise as the spread plate procedure for heterotrophic plate count. Fortunately, there are several steps you can take to ensure the success of your test.
Bacterial populations in sea water as determined by. Isolate single bacterial colonies by the streakplating method. Pour plate method for isolating bacteria membrane solutions. Iii testing methods in food microbiology tibor deak encyclopedia of life support systems eolss from the edge of the petri dish toward the center. The microbiology society, in association with the microbiology in schools advisory committee misac. 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. Microbiological examination of nonsterile products. In this method, fixed amount of inoculum generally 1 ml from a brothsample is placed in the center of sterile petri dish using a sterile pipette.
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. Withinoculants prepared from presterilized peat, viable numbers ofrhizobia may be determined by the pour, spread, and drop plate methods. The agar medium is maintained at the temperature of 45 c and the diluted suspension is inoculated and mixed well. Counting with colonyforming units requires culturing the microbes and counts only viable cells, in contrast with microscopic examination which counts all.
Here are the steps we follow in our laboratory to successfully perform the pour plate method. Results from these analyses were compared statistically. An introduction to microbiology, aseptic technique and safety preparation safety guidelines 1 risk assessment 2 good microbiological laboratory practice gmlp 3 spillage management 3 aerosols 3. Pour plate method the pour plate, like other viable plate count methods, involves adding a sample to a solid medium that will support microbial growth incubating. Pour plate technique page 56 for bacterial enumeration david b. Mar 08, 2018 download a pdf of our pour plate best practices and instructions. Pour plate technique for the isolation of microorganism. A comparison of pour plate and spread plate methods raymond h. Streak plate 11 pour plate 12 using a spreader spread plate 14 working with moulds 15 incubation 16 in conclusion. On the other hand, in pour plate method it doesnt happen. Counting with colonyforming units requires culturing the microbes and counts only viable cells, in contrast. Viable counts of bacteriaa new method for facultative anaerobes. Microbiology is a popular option for practical work in schools. The pour plate technique can be used to determine the number of microbes ml in a specimen.
Both methods rely on dilution of bacterial cells in a sample. Microbiological assay of antibiotics using cup plate method. The process may seem simple melt, pipette, pour, swirl, incubate, but errors have been known to occur. This method often is used to count the number of microorganisms in a mixed sample, which is added to a molten agar medium prior to its solidification. The colonies on the plate can then be counted and the concentration of bacteria in the original culture can be calculated. Download a pdf of our pour plate best practices and instructions. In certain oceanic areas samples as large as 5 to 10 ml may be required. Pourplate and subculture techniques an alternative method for using agar plates to obtain isolated colonies, other than streaking their surfaces, is to prepare a pour plate.
The pour plate method is not widely used but may be more convenient in some instances and some experienced workers prefer the pour plate method for isolating bacteria. Pour plate method is usually the method of choice for counting the number of colonyforming bacteria present in a liquid specimen. Sep 09, 2014 this general microbiology practical lecture explains the pour plate method of bacterial culture and culture media. Bacteriological water analysis is a method of analysing water to estimate the numbers of bacteria present and, if needed, to find out what sort of bacteria they are. Uk standards for microbiology investigations issued by the standards unit, public health england amendment table each uk smi method has an individual record of amendments. In pour plate culture technique, successive dilutions of the inoculum serially diluting the original specimen of old broth culture is added to. What advantage does the streakplate method have over the pourplate method. The tac can be conducted using a number of microbiological methods. 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. Streak plate method principle, methods, significance. The density of colonial growth was enumerated by comparison with a set of prepared standards calibrated by the pour. The pour plate method is an economical way for pharmaceutical, contract and even food. Pdf lab report of microbiology akbar haqi academia. We thrive on creating innovative biological reference materials that make microbiologists lives easier.
However, these techniques cannot provide real time data and require a. Viable is defined as the ability to multiply via binary fission under the controlled conditions. The speciman is serially diuted more than one times as the density of the original speciman is unknown. Pour plate method is neither as accurate nor as precise as the spread plate procedure for. It is assumed that each bacterial colony arises from an. A colonyforming unit cfu, cfu, cfu is a unit used in microbiology to estimate the number of viable bacteria or fungal cells in a sample. Streak plate 11 pour plate 12 using a spreader spread plate 14 working with moulds 15 incubation 16.
Serial dilution, pour plates, and enumeration of bacteria introduction the number of bacteria in a small sample can be startling. The liquid state permits the through out distribution within the medium. Microbial cells often occur as clumps, clusters, chains or pairs in foods, and may not be well distributed irrespective of the mixing and dilution of the sample. 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. Micro lab 5 pour plate and streak plate flashcards quizlet. Pour plate technique for bacterial enumeration david b. The plates are then incubated under conditions that permit microbial reproduction so that colonies develop that can be seen without the aid of a microscope. The most common method for determining the total viable count is the pour plate method. The pour plate method is an economical way for pharmaceutical, contract and even food laboratories to perform tests focused on a specific number of bacteria. The count of bacterial cells should be multiplied by dilution factor to work.
Inoculum refers to microorganisms, bacteria or fungi that grow in or on the nutrient agar. The most commonly used method in the laboratory for isolating microbes is the streak plate, and to a lesser extent, the pour plate. Whenlarge numbers ofsamples are plated, as happens during routine quality controlchecks,the methodchosenshouldeconomizeontheplatingmediaandpetri dishes. Total viable count an overview sciencedirect topics. Basic practical microbiology why microbiology matters. The tubes of medium with the serial dilutions of bacteria were solidified by cooling. An introduction to microbiology, aseptic technique and safety. Visit our website for technical documents, illustrated instructions, instructional videos, faqs and more. Aug 15, 2019 spread plate technique principle, procedure and uses. It is a microbiological analytical procedure which uses samples of water and from these samples determines the concentration of bacteria.
Conventional microbiology plating techniques such as the spread or pour plate method is used to measure bacterial growth 18. The tubes are then incubated for a standard time at a standard temperature. The dilution or isolation by streaking method was first developed by loeffler and gaffky in kochs laboratory, which involves the dilution of bacteria by systematically streaking them over the exterior of the agar in a petri dish to obtain isolated colonies which. Modification of the procedure may inpourplate methodfor petri dishes 9cm in diameter, add to clude, for example, the dish 1ml of the sample prepared as described under prepara 1 an increase in the volume of the diluent or culture medium. Unsubscribe from microbiology at the university of lincoln, uk. The total number of colonies equals the number of viable bacterial cells. Determination of bacillus cereus in foods and beverages or determination of ae robic mesophilic spore formers 6 3. Spread plate technique principle, procedure and uses. So mostly, through comparing the counts by both methods, less counts are. Agar pour plate methodsamples of sea water estimated to produce between 20 and 500 colonies per plate were transferred aseptically to sterile gomm plastic petri plates. The total viable count is obtained by adding the counts from the tac and the tymc. The density of colonial growth was enumerated by comparison with a set of prepared standards calibrated by the pourplate technique.
Pdf microorganisms are present on all inanimate surfaces creating. In microbiology, streaking is a technique used to isolate a pure strain from a single species of microorganism, often bacteria. Streak plate 11 pour plate 12 using a spreader spread plate 14 working with moulds 15. The fda bam recommends filling plates with 12 ml to 15 ml of agar. Best practices for pour plate method according to a consensus of views, it is recommended to keep the molten agar in the water bath for no more than 3 to 4 hours. This general microbiology practical lecture explains the pour plate method of bacterial culture and culture media. A short instructional video to teach you how to sub culture bacteria by pour plating. Pour plate technique procedure, advantages, limitations. Some microorganism species may recover better on spread plates than pour plates. Before inoculating and pouring molten nutrient agar. A successful spread plate will have a countable number of isolated bacterial colonies evenly distributed on the plate. Spread plate technique principle, procedure, advantages. What is the importance of a pour plate in microbiology. Basic practical microbiology a manual by society for general.