hello I'm Dr Carla field in this video I will explain the serial dilution process and demonstrate how to perform dilutions when using the microbiologics E power product dilution is the process of making a solution weaker or less concentrated in microbiology serial dilutions or log dilutions are used to decrease a bacterial population to a required concentration the purpose is to achieve an appropriate concentration for a specific test method or to achieve accountable augre plate a single log delution is a 10-fold solution which means the concentration is decreased by a multiple of 10 to complete a 10-fold solution the ratio must be 1 to 10 the one in the ratio represents the amount of sample added and the 10 represents the total size of the final sample for instance a sample size of 1 ml would be added to 9 millit of diluent to equal a total of 10 MERS before we can move on to multiple Solutions it is important to understand decimal numbers and scientific notation decimal numbers can be converted to scientific notation by moving the decimal place the same number of places as the exponential number in this example if we start with 100 and and move the decimal two places to the left the final result will be 1.0 * 10 second we use multiple dilutions to decrease the sample concentration by multiple logs here is an example if the concentration starts at 35,000 cfu per milliliter or 10 4th and 35 cfu per milliliter is the target concentration we would do three serial delusions we would take 1 M from the initial tube and place it in 9 millit this would equal 3,500 cfu per milliliter or 10 3r another delution would take the concentration to 350 cfu per milliliter or 10 the second and the final dilution would equal 35 cfu per mil our Target concentration now I will show you how to perform a multiple dilution series with microbiologics E power E7 first label the plates with the dilution factor next using sterile forceps Place one pellet into 10 MERS of pre-warmed phosphate buffer Vortex the microorganism suspension to achieve a homogeneous suspension pipet 1 ml from the suspension into 9 ml of phosphate buffer repeat this process until all the tubes have been diluted be sure to hold your pipet vertically to achieve maximum accuracy repeat this process until all the tubes have been diluted [Music] plate 1 ml from each tube use a spreader to distribute the inoculum evenly that place the plates in an incubator overnight these are our plates after the overnight incubation these results demonstrate why it is necessary to do serial dilutions most of these gave us either a full line of bacterial growth or two numerous to count colonies our final dilution gave us an easily countable plate for more technical information visit us online or contact our technical support team