ASSESSMENT NUMBER: Rewritten
The inactivation curve is done by plotting population against time at a specified temperature (Gazso & Ponta, 2005). But since the population is usually in very large numbers, it is always advisable to use the log of microorganisms. The ensuing issue is therefore that the D-value is read from the line of best fit. Afterwards the D – value of the thermal processes can be determined by considering the change in temperature over change in the log and is therefore an estimate of one log cycle at a specified temperature (Gera, 2011; Ogata, & Shibata, 2008).
For all the graphs, X axis are the plot for time (sec) whereas y axis represents microbial population (cfu/ml).
Inactivation Curves for each Set of Results
Explanation for the shapes of the inactivation curves
For all the curves, the population decreases as the time of decontamination. This is a clear indication that the bacteria population is reduced on further decontamination. However, the situation changes after a minute of heating as time increase but population for the Streptococcus faecalis and E.Coli almost remains the same. The population of Staphylococcus aureus changes at 2 minutes of decontamination.
This indicates that the bacteria became inactive and succumbed to the high temperatures long time.
Appropriate data to determine the D values* for each organism and reasons for the choice
The data selected for the three vegetative bacteria are as follows: 20oC for Staphylococcus aureus, 20oC for Streptococcus faecalis and 35oC for Escherichia coli. The reason is that from the representation of the curves, these will give best linear lines for ease of D-value calculation (Frascella, Gilbert, Fernandez, & Hendler, 2000).
The Graph showing D-value of Staphylococcus aureus at 20oC
The Graph showing D-value of Streptococcus faecalis at 20oC
The Graph showing D-value of Escherichia coli at 35oC
Determination of D values* for each organism and comments
The overall formula for D_value is
T2 â€“ T1
D = ______________________
Log10 N1 â€“ Log10 N2
For Staphylococcus aureus the D values* are:
D values* at 5oC
D values* at 20oC
Dt20=5-1/log (4*10^7)-log (1.5*10^2)
D values* at 35oC
The D values* for Streptococcus feacalis are:
D values * at 5oC
D values* at 20oC
D values* at 35oC
The D values* for E. coli are:
D values* at 5oC
Dt5=5-1/log (4.6*10^7)-log (4.4*10^2)
D values * at 20oC
D values * at 35oC
It can be concluded that for Staphylococcus aureus, the highest inactivation rate was at 35oC, whereas the lowest was at 5oC. This shows it takes longer to reduce microbial load by 90% at low temperature this applies to the three organisms.
The highest inactivation rate for E.coli was 0.88020 cfu/ml/minute at 35oC, and the lowest rate was at 5oC (Block, 2000; Taniguchi, Stanley, H., & Ludwig, 2002; Mullan, 2007; Young & Reichert, 1997; Juneja, Huang, & Marks, 2001; Zhang, Zheng, & Zhi, 2007).
In conclusion, as the temperature increased the rate of inactivation increased, and for Staphylococcus aureus and E.coli, 35oC was the optimum temperature for inactivation by thermal-chemical disinfection.
Our Service Charter
Excellent Quality / 100% Plagiarism-FreeWe employ a number of measures to ensure top quality essays. The papers go through a system of quality control prior to delivery. We run plagiarism checks on each paper to ensure that they will be 100% plagiarism-free. So, only clean copies hit customers’ emails. We also never resell the papers completed by our writers. So, once it is checked using a plagiarism checker, the paper will be unique. Speaking of the academic writing standards, we will stick to the assignment brief given by the customer and assign the perfect writer. By saying “the perfect writer” we mean the one having an academic degree in the customer’s study field and positive feedback from other customers.
Free RevisionsWe keep the quality bar of all papers high. But in case you need some extra brilliance to the paper, here’s what to do. First of all, you can choose a top writer. It means that we will assign an expert with a degree in your subject. And secondly, you can rely on our editing services. Our editors will revise your papers, checking whether or not they comply with high standards of academic writing. In addition, editing entails adjusting content if it’s off the topic, adding more sources, refining the language style, and making sure the referencing style is followed.
Confidentiality / 100% No DisclosureWe make sure that clients’ personal data remains confidential and is not exploited for any purposes beyond those related to our services. We only ask you to provide us with the information that is required to produce the paper according to your writing needs. Please note that the payment info is protected as well. Feel free to refer to the support team for more information about our payment methods. The fact that you used our service is kept secret due to the advanced security standards. So, you can be sure that no one will find out that you got a paper from our writing service.
Money Back GuaranteeIf the writer doesn’t address all the questions on your assignment brief or the delivered paper appears to be off the topic, you can ask for a refund. Or, if it is applicable, you can opt in for free revision within 14-30 days, depending on your paper’s length. The revision or refund request should be sent within 14 days after delivery. The customer gets 100% money-back in case they haven't downloaded the paper. All approved refunds will be returned to the customer’s credit card or Bonus Balance in a form of store credit. Take a note that we will send an extra compensation if the customers goes with a store credit.
24/7 Customer SupportWe have a support team working 24/7 ready to give your issue concerning the order their immediate attention. If you have any questions about the ordering process, communication with the writer, payment options, feel free to join live chat. Be sure to get a fast response. They can also give you the exact price quote, taking into account the timing, desired academic level of the paper, and the number of pages.