Quantitave Plating

BioSci 101 science laboratoryoratory particle 810 quantifiable PLATING use The purpose of this lab is to see the set up of pasteurisation darn emphasizing the exercise for serial dilutions. part See references (1) RESULTS As the dilution factor change magnitude for both the naked take out (un change integrity) and change integrity draw sample distributions, the number of colonies decreased. The number of electric cells/mL in the pasteurized take out sample is considerably little than the number of cells/mL in the primitive draw sample. warm (UNPASTEURIZED) assay Dilution part modus operandi of Colonies reckon of cells/mL 10-3 TMTC TMTC 0-4 TMTC TMTC 10-5 TMTC TMTC 10-6 284 284,000,000 cells/mL 10-7 44 440,000,000 cells/mL AVERAGE 362,000,000 cells/mL PASTEURIZED SAMPLE Dilution Factor Number of Colonies Number of cells/mL 10-3 71 71,000 cells/mL 10-4 9 (TLTC) TLTC 10-5 6 (TLTC) TLTC 10-6 1 (TLTC) TLTC 10-7 12 (TLTC) TLTC AVERAGE 71,000 cells/mL DISCUSS ION/CONCLUSIONS Pasteurization, a process named after scientist Louis Pasteur, involves the application of wake to destroy the bulk of serviceman pathogens in foods.In the dairy farm industry, pasteurization involves the modifying of all particle of draw or draw product to a specific temperature for a specified dot of time without allowing recontamination of that milk or milk product during the heat treatment process. (2) For earthly concern health purposes, pasteurization is the process of devising milk and milk products safe for human consumption by destroying all bacterium that may be harmful to health. (2) A serial dilution is a laboratory technique in which a substance is decreased in ingress in a series of relative amounts. Dilutions are normally made in septuples of 10. 3) The viable crustal abode deem procedure allowed for live cells in the milk samples to be analyzed. The raw milk (unpasteurized) sample demo in like manner many dependency forming units to count in the world-class three dilutions of 10-3, 10-4, and 10-5. The 10-6 dilution present 284,000,000 cells/mL and the 10-7 dilution exhibit 440,000,000 cells/mL. This demonstrates that raw milk contains a messiness of bacteria up to now after multiple serial dilutions. In the 10-3 pasteurized sample, the plateful exhibited 71,000 cells/mL. The results of the additional dilution samples contained similarly few dependency forming units to count.However, in the 10-7 dilution, although the plate demo 12 colonies, there should lease been no colony forming units on this plate. The reasons for this could beget been that this sample was soil from double-dipping the sample originally dispensing it onto the plate or when using the pipette, it erroneously was inserted in a higher niggardliness sample and then(prenominal) immediately to a lower concentration sample originally it was dispensed onto the plate. The results bespeak that pasteurization kills around pathoge ns in milk by skeleton exposure to relatively high temperature.This was demonstrated most beneficially with the 10-6 and 10-7 dilutions wherein the raw milk exhibited 284,000,000 cells/mL and 440,000,000 cells/mL respectively and the pasteurized milk had too few cell colony forming units to flush count. Unpasteurized milk is not whole for people to drink. For example, in a demand performed in declination of 2001, the bacteria Campylobacter jejuni, a microaerophilic bacteria commonly erect in animal feces, was found in unpasteurized milk at an organic dairy farm in Wisconsin and caused 75 people, ages 2 to 63, to become ill. 4) Therefore, pasteurized milk is inseparable for ensuring good quality, roughly bacteria-free drinkable milk. REFERENCES 1. BioSci 101, Section 810 PowerPoint Lab 9A 2. http//www. foodsci. uoguelph. ca/dairyedu/pasteurization. html 3. BioSci 101, full general Survey of Microbiology research lab Supplement dec 2012 4. http//foodsafety. ksu. edu/arti cles/1138/Raw_Milk_Outbreak_Table. pdf